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In vivo tumours are highly heterogeneous, often comprising regions of hypoxia and necrosis. Radiotherapy significantly alters the intratumoural composition. Moreover, radiation-induced cell death may occur via a number of different mechanisms that act over different timescales. Dead material may therefore occupy a significant portion of the tumour volume for some time after irradiation and may affect the subsequent tumour dynamics. We present a three phase tumour growth model that accounts for the effects of radiotherapy and use it to investigate how dead material within the tumour may affect the spatio-temporal tumour response dynamics. We use numerical simulation of the model equations to characterise qualitatively different tumour volume dynamics in response to fractionated radiotherapy. We demonstrate examples, and associated parameter values, for which the properties of the dead material significantly alter the observed tumour volume dynamics throughout treatment. These simulations suggest that for some cases it may not be possible to accurately predict radiotherapy response from pre-treatment, gross tumour volume measurements without consideration of the dead material within the tumour.

Purpose: Radiotherapy prescription dose and dose fractionation protocols vary little between individual patients having the same tumor grade and stage. To personalize radiotherapy a predictive model is needed to simulate radiation response. Previous modeling attempts with multiple variables and parameters have been shown to yield excellent data fits at the cost of non-identifiability and clinically unrealistic results. Materials and methods: We develop a mathematical model based on a proliferation saturation index (PSI) that is a measurement of pre-treatment tumor volume-to-carrying capacity ratio that modulates intrinsic tumor growth and radiation response rates. In an adaptive Bayesian approach, we utilize an increasing number of data points for individual patients to predict patient-specific responses to subsequent radiation doses. Results: Model analysis shows that using PSI as the only patient-specific parameter, model simulations can fit longitudinal clinical data with high accuracy ( R 2 =0.84). By analyzing tumor response to radiation using daily CT scans early in the treatment, response to the remaining treatment fractions can be predicted after two weeks with high accuracy (c-index = 0.89). Conclusion: The PSI model may be suited to forecast treatment response for individual patients and offers actionable decision points for mid-treatment protocol adaptation. The presented work provides an actionable image-derived biomarker prior to and during therapy to personalize and adapt radiotherapy.

Radiotherapy has long been the mainstay of treatment for patients with head and neck cancer and has traditionally involved a stage-dependent strategy whereby all patients with the same TNM stage receive the same therapy. We believe there is a substantial opportunity to improve radiotherapy delivery beyond just technological and anatomical precision. In this Series paper, we explore several new ideas that could improve understanding of the phenotypic and genotypic differences that exist between patients and their tumours. We discuss how exploiting these differences and taking advantage of precision medicine tools-such as genomics, radiomics, and mathematical modelling-could open new doors to personalised radiotherapy adaptation and treatment. We propose a new treatment shift that moves away from an era of empirical dosing and fractionation to an era focused on the development of evidence to guide personalisation and biological adaptation of radiotherapy. We believe these approaches offer the potential to improve outcomes and reduce toxicity., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

PurposeReducing radiation treatment dose could improve the quality of life (QOL) of patients with good-risk human papillomavirus-associated oropharyngeal squamous cell carcinoma (OPSCC). Whether reduced-dose radiation produces disease control and QOL equivalent to standard chemoradiation is not proven.Patients and methodsIn this randomized, phase II trial, patients with p16-positive, T1-T2 N1-N2b M0, or T3 N0-N2b M0 OPSCC (7th edition staging) with ≤ 10 pack-years of smoking received 60 Gy of intensity-modulated radiation therapy (IMRT) over 6 weeks with concurrent weekly cisplatin (C) or 60 Gy IMRT over 5 weeks. To be considered for a phase III study, an arm had to achieve a 2-year progression-free survival (PFS) rate superior to a historical control rate of 85% and a 1-year mean composite score ≥ 60 on the MD Anderson Dysphagia Inventory (MDADI).ResultsThree hundred six patients were randomly assigned and eligible. Two-year PFS for IMRT + C was 90.5% rejecting the null hypothesis of 2-year PFS ≤ 85% (P = .04). For IMRT, 2-year PFS was 87.6% (P = .23). One-year MDADI mean scores were 85.30 and 81.76 for IMRT + C and IMRT, respectively. Two-year overall survival rates were 96.7% for IMRT + C and 97.3% for IMRT. Acute adverse events (AEs) were defined as those occurring within 180 days from the end of treatment. There were more grade 3-4 acute AEs for IMRT + C (79.6% v 52.4%; P < .001). Rates of grade 3-4 late AEs were 21.3% and 18.1% (P = .56).ConclusionThe IMRT + C arm met both prespecified end points justifying advancement to a phase III study. Higher rates of grade ≥ 3 acute AEs were reported in the IMRT + C arm.

Purpose: A planning strategy was developed and the utility of online‐adaptation with the Ethos CBCT‐guided ring‐gantry adaptive radiotherapy (ART) system was evaluated using retrospective data from Head‐and‐neck (H&N) patients that required clinical offline adaptation during treatment. Methods: Clinical data were used to re‐plan 20 H&N patients (10 sequential boost (SEQ) with separate base and boost plans plus 10 simultaneous integrated boost (SIB)). An optimal approach, robust to online adaptation, for Ethos‐initial plans using clinical goal prioritization was developed. Anatomically‐derived isodose‐shaping helper structures, air‐density override, goals for controlling hotspot location(s), and plan normalization were investigated. Online adaptation was simulated using clinical offline adaptive simulation‐CTs to represent an on‐treatment CBCT. Dosimetric comparisons were based on institutional guidelines for Clinical‐initial versus Ethos‐initial plans and Ethos‐scheduled versus Ethos‐adapted plans. Timing for five components of the online adaptive workflow was analyzed. Results: The Ethos H&N planning approach generated Ethos‐initial SEQ plans with clinically comparable PTV coverage (average PTVHigh V100% = 98.3%, Dmin,0.03cc = 97.9% and D0.03cc = 105.5%) and OAR sparing. However, Ethos‐initial SIB plans were clinically inferior (average PTVHigh V100% = 96.4%, Dmin,0.03cc = 93.7%, D0.03cc = 110.6%). Fixed‐field IMRT was superior to VMAT for 93.3% of plans. Online adaptation succeeded in achieving conformal coverage to the new anatomy in both SEQ and SIB plans that was even superior to that achieved in the initial plans (which was due to the changes in anatomy that simplified the optimization). The average adaptive workflow duration for SIB, SEQ base and SEQ boost was 30:14, 22.56, and 14:03 (min: sec), respectively. Conclusions: With an optimal planning approach, Ethos efficiently auto‐generated dosimetrically comparable and clinically acceptable initial SEQ plans for H&N patients. Initial SIB plans were inferior and clinically unacceptable, but adapted SIB plans became clinically acceptable. Online adapted plans optimized dose to new anatomy and maintained target coverage/homogeneity with improved OAR sparing in a time‐efficient manner. [ABSTRACT FROM AUTHOR]

Introduction: Radiation therapy (RT) is one of the most common anticancer therapies. Yet, current radiation oncology practice does not adapt RT dose for individual patients, despite wide interpatient variability in radiosensitivity and accompanying treatment response. We have previously shown that mechanistic mathematical modeling of tumor volume dynamics can simulate volumetric response to RT for individual patients and estimation personalized RT dose for optimal tumor volume reduction. However, understanding the implications of the choice of the underlying RT response model is critical when calculating personalized RT dose. Methods: In this study, we evaluate the mathematical implications and biological effects of 2 models of RT response on dose personalization: (1) cytotoxicity to cancer cells that lead to direct tumor volume reduction (DVR) and (2) radiation responses to the tumor microenvironment that lead to tumor carrying capacity reduction (CCR) and subsequent tumor shrinkage. Tumor growth was simulated as logistic growth with pre-treatment dynamics being described in the proliferation saturation index (PSI). The effect of RT was simulated according to each respective model for a standard schedule of fractionated RT with 2 Gy weekday fractions. Parameter sweeps were evaluated for the intrinsic tumor growth rate and the radiosensitivity parameter for both models to observe the qualitative impact of each model parameter. We then calculated the minimum RT dose required for locoregional tumor control (LRC) across all combinations of the full range of radiosensitvity and proliferation saturation values. Results: Both models estimate that patients with higher radiosensitivity will require a lower RT dose to achieve LRC. However, the two models make opposite estimates on the impact of PSI on the minimum RT dose for LRC: the DVR model estimates that tumors with higher PSI values will require a higher RT dose to achieve LRC, while the CCR model estimates that higher PSI values will require a lower RT dose to achieve LRC. Discussion: Ultimately, these results show the importance of understanding which model best describes tumor growth and treatment response in a particular setting, before using any such model to make estimates for personalized treatment recommendations. [ABSTRACT FROM AUTHOR]

• New Deep Learning-based auto-segmentation algorithm for H&N OARs described. • Produced higher comparison scores compared to previously published. • 93% of the auto-segmented structures were subjectively judged as clinically useful. • The training dataset must be congruent with the expectations of the evaluator. • Performance can differ when the same algorithm is trained at different institutions. To introduce and validate a newly developed deep-learning (DL) auto-segmentation algorithm for head and neck (HN) organs at risk (OARs) and to compare its performance with a published commercial algorithm. A total of 864 HN cancer cases were available to train and evaluate a prototype algorithm. The algorithm is based on a fully convolutional network with combined U-Net and V-net. A Dice loss plus Cross-Entropy Loss function with Adam optimizer was used in training. For 75 validation cases, OAR sets were generated with three DL-based models (A: the prototype model trained with gold data, B: a commercial software trained with the same data, and C: the same software trained with data from another institution). The auto-segmented structures were evaluated with Dice similarity coefficient (DSC), Hausdorff distance (HD), voxel-penalty metric (VPM) and DSC of area under dose-volume histograms. A subjective qualitative evaluation was performed on 20 random cases. Overall trend was for the prototype algorithm to be the closest to the gold data by all five metrics. The average DSC/VPM/HD for algorithms A, B, and C were 0.81/84.1/1.6 mm, 0.74/62.8/3.2 mm, and 0.66/46.8/3.3 mm, respectively. 93% of model A structures were evaluated to be clinically useful. The superior performance of the prototype was validated, even when trained with the same data. In addition to the challenges of perfecting the algorithms, the auto-segmentation results can differ when the same algorithm is trained at different institutions. [ABSTRACT FROM AUTHOR]

Abstract Background The utility of definitive radiotherapy (RT) for locoregionally advanced squamous cell carcinoma (SCC) of the larynx or hypopharynx in the setting of thyroid or cricoid cartilage invasion (TCCI) is controversial. A retrospective review of our experience was performed. Methods Our institutional database of patients with SCC of the head and neck treated with radiotherapy (90% received concurrent systemic therapy) between 1995 and 2009 was queried. We identified 87 patients with T3-4 laryngeal or T4 hypopharyngeal cancer for whom initial head and neck imaging was available for review. Imaging of all patients was reviewed by a single radiologist specializing in neuroradiology. The presence and extent of TCCI was determined and used for stratification. Results Median follow-up was 34 months. TCCI was found in 25 (29%) patients, eight limited to the inner cortex and another 17 involving both cortices. Local control (LC) was not significantly affected by TCCI limited to the inner cortex. However, TCCI involving both cortices was correlated with diminished LC at 2 years compared to the group of patients with no or minor invasion (55% vs. 81%, p=0.045). However, TCCI involving both cortices was not associated with significantly reduced rates of survival with a functional larynx, or overall survival (OS). Conclusions Our results suggest that the rate of LC of T3-4 laryngeal or T4 hypopharyngeal SCC treated with definitive RT is not affected by TCCI of the inner cortex. Although decreased LC was significantly associated with TCCI involving both cortices, this factor did not appear to result in reduced rates of survival with a functional larynx or OS. Therefore, organ preservation may remain an option in these patients.

Background: Radiotherapy (RT) is an integral component in the treatment of head and neck cancer (HNC).We hypothesized there would be alterations in gene‐expression and pathway activity in HNC samples obtained in recurrent HNC that were previously treated with RT, when compared to RT‐naïve disease. Methods: Patient data was abstracted from a prospectively maintained database. Linear‐microarray analysis and supervised gene‐set enrichment‐analysis were employed to compare RT‐naive and recurrent disease after prior‐RT. Results: A total of 157 patients were analyzed, 96 (61%) were RT‐naive and 61 (39%) had RT.After radiation, there was upregulation of genes associated with angiogenesis, protein‐translation‐machinery, cell‐cycle regulation, and growth factors, and downregulation associated with Myc activity, and hypoxic response (all P <.001).Previously irradiated HNC was associated with downregulation in 19/42 genes in the Wnt/B‐catenin‐pathway (P =.045)and 119/199 genes involved in the MYC target pathway (P =.024). Conclusion: Patients with recurrences salvaged surgically post‐RT had significant alterations in gene‐expression and in Wnt/B‐catenin and MYC‐target pathways. These pathways may represent potential targets to prevent development of resistance to RT. [ABSTRACT FROM AUTHOR]

Background: Studies suggest treatment outcomes may vary between high (HVC)‐ and low‐volume centers (LVC). Radiation therapy (RT) for head and neck cancer (HNC) requires weeks of treatment, the inconvenience of which may influence a patient's choice for treatment location. We hypothesized that receipt of RT for HNC at a HVC would influence outcomes compared to patients evaluated at a HVC, but who chose to receive RT at a LVC. Methods: From 1998 to 2011, 1930 HNC patients were evaluated at a HVC and then treated with RT at either a HVC or LVC. Time‐to‐event outcomes and treatment factors were compared. Results: Median follow‐up was 34 months. RT was delivered at a HVC for 1368 (71%) patients and at a LVC in 562 (29%). Patients were more likely to choose HVC‐RT if they resided in the HVC's county or required definitive RT (all P < 0.001). HVC‐RT was associated with a significant improvement in 3‐year LRC (84% vs 68%), DFS (68% vs 48%), and OS (72% vs 57%) (all P < 0.001). On multivariate analysis (MVA), HVC‐RT independently predicted for improved LRC, DFS, and OS (all P < 0.05). Conclusions: In patients evaluated at a HVC, the choice of RT location was primarily influenced by their residing distance from the HVC. HVC‐RT was associated with improvements in LRC, DFS, and OS in HNC. As treatment planning and delivery are technically demanding in HNC, the choice to undergo treatment at a HVC may result in more optimal delivered dose, RT duration, and outcome. Patient choice to undergo radiation therapy at a high‐volume center (HVC) was primarily influenced by their residing distance from the HVC. HVC radiation treatment was associated with improvements in locoregional control, disease‐free survival, and overall survival in head and neck cancer. [ABSTRACT FROM AUTHOR]

Purpose: Intensity‐modulated radiation therapy (IMRT) has allowed optimization of three‐dimensional spatial radiation dose distributions permitting target coverage while reducing normal tissue toxicity. However, radiation‐induced normal tissue toxicity is a major contributor to patients’ quality of life and often a dose‐limiting factor in the definitive treatment of cancer with radiation therapy. We propose the next logical step in the evolution of IMRT using canonical radiobiological principles, optimizing the temporal dimension through which radiation therapy is delivered to further reduce radiation‐induced toxicity by increased time for normal tissue recovery. We term this novel treatment planning strategy “temporally feathered radiation therapy” (TFRT). Methods: Temporally feathered radiotherapy plans were generated as a composite of five simulated treatment plans each with altered constraints on particular hypothetical organs at risk (OARs) to be delivered sequentially. For each of these TFRT plans, OARs chosen for feathering receive higher doses while the remaining OARs receive lower doses than the standard fractional dose delivered in a conventional fractionated IMRT plan. Each TFRT plan is delivered a specific weekday, which in effect leads to a higher dose once weekly followed by four lower fractional doses to each temporally feathered OAR. We compared normal tissue toxicity between TFRT and conventional fractionated IMRT plans by using a dynamical mathematical model to describe radiation‐induced tissue damage and repair over time. Results: Model‐based simulations of TFRT demonstrated potential for reduced normal tissue toxicity compared to conventionally planned IMRT. The sequencing of high and low fractional doses delivered to OARs by TFRT plans suggested increased normal tissue recovery, and hence less overall radiation‐induced toxicity, despite higher total doses delivered to OARs compared to conventional fractionated IMRT plans. The magnitude of toxicity reduction by TFRT planning was found to depend on the corresponding standard fractional dose of IMRT and organ‐specific recovery rate of sublethal radiation‐induced damage. Conclusions: TFRT is a novel technique for treatment planning and optimization of therapeutic radiotherapy that considers the nonlinear aspects of normal tissue repair to optimize toxicity profiles. Model‐based simulations of TFRT to carefully conceptualized clinical cases have demonstrated potential for radiation‐induced toxicity reduction in a previously described dynamical model of normal tissue complication probability (NTCP). [ABSTRACT FROM AUTHOR]

Purpose Concurrent chemoradiotherapy (CRT) is the standard of care for many sites of locally advanced head and neck squamous cell carcinomas (LAHNC). However, on meta-analysis, the addition of chemotherapy did not improve survival for patients > 70 years. We hypothesized that elderly patients treated with CRT would have increased toxicity without similar improvements in survival. Methods A single-institution, IRB-approved retrospective study took place from 2005 to 2012 including 369 patients treated with CRT for LAHNC. Multivariate models for death at 3 months and death over time were developed using logistic regression and Cox modeling, respectively. Results Patients ≥ 70 years were treated less often with concurrent cisplatin dosed every 3 weeks (25.5% vs. 71.4%, respectively) and more often with weekly carboplatin (31.9% vs. 3.4%) than patients < 70 years ( n = 322; p < 0.001). Patients ≥ 70 years experienced increased toxicity during treatment with more frequently hospitalizations (36.2% vs. 21.1%; p = 0.02) and a lower rate of PEG removal at last follow-up or death (77.1% vs. 92.9%; p = 0.004). A higher proportion of patients ≥ 70 years died within 3 months (12.8% vs. 2.8%; p = 0.001) following CRT. Patients ≥ 70 had an increased risk of death at 3 months following CRT (odds ratio 5.19, 95% CI 1.64–16.41; p = 0.005) and worse survival over time (hazard ratio 2.30, 95% CI 1.34–3.93; p = 0.002). Conclusions Patients ≥ 70 years were more often treated with less toxic chemotherapy, yet experienced higher rates of hospitalization during treatment and increased rates of acute mortality following CRT. The efficacy of chemoradiotherapy for elderly patients should be evaluated in a prospective setting. [ABSTRACT FROM AUTHOR]

Background We hypothesized that radiotherapy (RT) would improve both local and regional control with Merkel cell carcinoma of the head and neck. Methods A single-institution institutional review board-approved study was performed including 113 patients with nonmetastatic Merkel cell carcinoma of the head and neck. Postoperative RT was delivered to the primary tumor bed (71.7% cases) ± draining lymphatics (33.3% RT cases). Results Postoperative local RT was associated with improved local control (3-year actuarial local control 89.4% vs 68.1%; p = .005; Cox hazard ratio [HR] 0.18; 95% confidence interval [CI] = 0.06-0.55; p = .002). Similarly, regional RT was associated with improved regional control (3-year actuarial regional control 95.0% vs 66.7%; p = .008; Cox HR = 0.09; 95% CI = 0.01-0.69; p = .02). Regional RT played an important role for both clinical node-negative patients (3-year regional control 100% vs 44.7%; p = .03) and clinical/pathological node-positive patients (3-year regional control 90.9% vs 55.6%; p = .047). Conclusion Local RT was beneficial for all patients with Merkel cell carcinoma of the head and neck, whereas regional RT was beneficial for clinical node-negative and clinical/pathological node-positive patients. © 2016 Wiley Periodicals, Inc. Head Neck 39: 48-55, 2017 [ABSTRACT FROM AUTHOR]

Background Given the aggressive behavior of advanced salivary malignancies, the purpose of the current study was to explore the utility of adjuvant chemoradiotherapy (CRT) in this population. Methods A retrospective study of salivary carcinomas treated from 1998 to 2013 with postoperative CRT (37 patients) or radiotherapy (RT; 103 patients) was completed. Results The decision to utilize adjuvant CRT versus RT was influenced by tumor grade and histology, cervical lymph node status, surgical margins, and perineural invasion. In both treatment cohorts, high locoregional control rates were obtained (79% for CRT vs 91% for RT; p = .031). Multivariate Cox regression analysis did not identify a difference in 3-year progression-free survival (PFS) with the use of CRT versus RT (hazard ratio [HR] = 0.783; 95% confidence interval [CI] = 0.396-1.549; p = .482). Conclusion Until prospective evidence is available, such as from Radiation Therapy Oncology Group 1008, the standard use of CRT for advanced salivary malignancies cannot be recommended. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016 [ABSTRACT FROM AUTHOR]

Background The majority of patients with locally advanced salivary gland carcinoma will die of the disease even after curative surgery. Few studies on adjuvant therapy have been conducted. In this study, we compared adjuvant chemoradiotherapy (CRT) with adjuvant radiotherapy among the older patient population. Methods Surveillance, Epidemiology, and End Results (SEER)-Medicare database (1992-2009) was analyzed. Eligible cases were those receiving curative surgery followed by adjuvant therapy. Outcomes were overall survival and toxicity. Results Analyses included 741 patients: 641 patients (86.5%) received adjuvant radiotherapy and 100 (13.5%) received adjuvant CRT. The median overall survival was 41.0 months with adjuvant radiotherapy and 24 months with CRT. Both multivariable and propensity score-adjusted analyses indicated that adjuvant CRT was associated with an increased mortality (hazard ratio [HR]: 1.39; 95% confidence interval [CI]: 1.07-1.79 and HR: 1.49; 95% CI: 1.14-1.94, respectively). Toxicity rates were significantly higher in the CRT group. Conclusion Treatment with adjuvant CRT was associated with an increased mortality and toxicity when compared to adjuvant radiotherapy alone. © 2015 Wiley Periodicals, Inc. Head Neck 38: 863-870, 2016 [ABSTRACT FROM AUTHOR]

Introduction: Mucosal melanoma of the head and neck is a rare disease with limited data available on outcomes; therefore, we reviewed our institutional experience.Methods: An institutional database was queried and 38 patients with head and neck mucosal melanoma were identified. Charts were abstracted and local control (LC), progression-free survival (PFS) and overall survival (OS) were calculated.Results: Most patients had T4 disease (86%), although nodes were positive in 11%. En bloc or endoscopic resection was performed on 93%. Adjuvant or definitive radiotherapy to a median dose of 60 Gy was utilized in 90%. Chemotherapy was given in 21%, and 16% received interferon. Three-year LC, PFS and OS were 90%, 48% and 59%, respectively. Median OS was 4.6 years. Site of first failure was distant in 52% of cases.Conclusion: With aggressive therapy median OS was 4.6 years in this cohort. Distant recurrence remains the primary mode of failure. It may be reasonable to include mucosal melanoma patients in trials of systemic agents along with high-risk cutaneous melanomas. [ABSTRACT FROM AUTHOR]

Background: Determining the optimal follow-up for patients can help maximize the use of health care resources. This is particularly true in a growing epidemic such as human papillomavirus-positive oropharyngeal squamous cell carcinoma (HPV+OPSCC). The objective of the current study was to evaluate time to disease recurrence or late toxicity in this cohort of patients to optimize patient management.Methods: An institutional database identified 232 patients with biopsy-proven, nonmetastatic HPV+OPSCC who were treated with radiotherapy. A retrospective review was conducted in patients who were followed every 3 months for the first year, every 4 months in year 2, and every 6 months in years 3 to 5. Late toxicity (grade ≥ 3; toxicity was scored based on National Cancer Institute Common Terminology Criteria for Adverse Events [version 4]), locoregional control, distant control, and overall survival were assessed.Results: The median follow-up was 33 months. Based on Radiation Therapy Oncology Group (RTOG) 0129 study risk groupings, patients were either considered to be at low (162 patients; 70%) or intermediate (70 patients; 30%) risk. Concurrent systemic therapy was used in 85% of patients (196 patients). The 3-year locoregional control, distant control, and overall survival rates were 94%, 91%, and 91%, respectively. Late toxicity occurred in 9% of patients (21 patients). Overall, 64% of toxicity and failure events occurred within the first 6 months of follow-up, with a < 2% event incidence noted at each subsequent follow-up. Only 4 patients experienced their first event after 2 years.Conclusions: HPV+OPSCC has a low risk of disease recurrence and late toxicity after treatment; approximately two-thirds of events occur within the first 6 months of follow-up. These data suggest that it may be reasonable to reduce follow-up in patients with HPV+OPSCC to every 3 months for the first 6 months, every 6 months for the first 2 years, and annually thereafter. [ABSTRACT FROM AUTHOR]

Background: Although altered protocols that challenge conventional radiation fractionation have been tested in prospective clinical trials, we still have limited understanding of how to select the most appropriate fractionation schedule for individual patients. Currently, the prescription of definitive radiotherapy is based on the primary site and stage, without regard to patient-specific tumor or host factors that may influence outcome. We hypothesize that the proportion of radiosensitive proliferating cells is dependent on the saturation of the tumor carrying capacity. This may serve as a prognostic factor for personalized radiotherapy (RT) fractionation. Methods: We introduce a proliferation saturation index (PSI), which is defined as the ratio of tumor volume to the host-influenced tumor carrying capacity. Carrying capacity is as a conceptual measure of the maximum volume that can be supported by the current tumor environment including oxygen and nutrient availability, immune surveillance and acidity. PSI is estimated from two temporally separated routine pre-radiotherapy computed tomography scans and a deterministic logistic tumor growth model. We introduce the patient-specific pre-treatment PSI into a model of tumor growth and radiotherapy response, and fit the model to retrospective data of four non-small cell lung cancer patients treated exclusively with standard fractionation. We then simulate both a clinical trial hyperfractionation protocol and daily fractionations, with equal biologically effective dose, to compare tumor volume reduction as a function of pretreatment PSI. Results: With tumor doubling time and radiosensitivity assumed constant across patients, a patient-specific pretreatment PSI is sufficient tofit individual patient response data (R2 = 0.98). PSI varies greatly between patients (coefficient of variation >128 %) and correlates inversely with radiotherapy response. For this study, our simulations suggest that only patients with intermediate PSI (0.45-0.9) are likely to truly benefit from hyperfractionation. For up to 20 % uncertainties in tumor growth rate, radiosensitivity, and noise in radiological data, the absolute estimation error of pretreatment PSI is <10 % for more than 75 % of patients. Conclusions: Routine radiological images can be used to calculate individual PSI, which may serve as a prognostic factor for radiation response. This provides a new paradigm and rationale to select personalized RT dose-fractionation. [ABSTRACT FROM AUTHOR]

BACKGROUND Desmoplastic melanoma may have a high risk of local recurrence after wide excision. The authors hypothesized that adjuvant radiotherapy (RT) would improve local control in patients with desmoplastic melanoma, resulting in at least a 10% absolute decrease in local recurrence rate. METHODS A total of 277 patients from 1989 through 2010 who were treated for nonmetastatic desmoplastic melanoma by surgery with or without adjuvant RT were reviewed. Clinicopathologic and treatment variables were assessed with regard to their role in local control. RESULTS A total of 113 patients (40.8%) received adjuvant RT. After a median follow-up of 43.1 months, adjuvant RT was found to be independently associated with improved local control on multivariable analysis (hazards ratio, 0.15; 95% confidence interval, 0.06-0.39 [ P < .001]). Among 35 patients with positive resection margins, 14% who received RT developed a local recurrence versus 54% who did not ( P = .004). In patients with negative resection margins, there was a trend ( P = .09) toward improved local control with RT. In patients with negative resection margins and traditionally high-risk features, including a head and neck tumor location, a Breslow depth > 4 mm, or a Clark level V tumor, RT was found to significantly improve local control ( P < .05). The data from the current study would suggest that patients who would be good candidates for omitting RT included those with negative resection margins, a Breslow depth ≤ 4 mm, and either no perineural invasion present or a non-head and neck tumor location. CONCLUSIONS RT for desmoplastic melanoma was independently associated with improved local control. Patients with positive resection margins or deeper tumors appeared to benefit the most from RT, whereas selected low-risk patients can safely omit RT. Cancer 2014;120:1369-1378. © 2013 American Cancer Society. [ABSTRACT FROM AUTHOR]

Data have emerged that the addition of concurrent chemotherapy to radiation can lead to swallowing dysfunction that may have an impact on patient quality of life and lead to significant morbidities such as poor nutritional status, enteral feeding tube dependence, and aspiration pneumonia. Although intensity-modulated radiation therapy (IMRT) for head and neck cancer was initially developed to spare the parotid gland to reduce xerostomia, attention has recently focused on its utility to selectively decrease radiation dose to specified anatomic structures responsible for a functional swallow. Recent reports have proposed a variety of dose thresholds or constraints to these swallowing-related structures, which may guide IMRT planning with the aim of reducing dysphagia. This critical review of the current literature assesses the feasibility of IMRT to maintain swallowing function and appraises the various dosimetric parameters that have been proposed to help minimize long-term dysphagia. © 2013 Wiley Periodicals, Inc. Head Neck 36: 291-298, 2014 [ABSTRACT FROM AUTHOR]

Background Over the past decade, intensity-modulated radiation therapy (IMRT) has gained widespread use in the treatment of head and neck cancer. Methods All patients with squamous cell carcinoma of the oropharynx treated with primary IMRT with or without chemotherapy over a 5-year period were reviewed. Outcomes and morbidity were analyzed and compared with previously published data. Results In all, 170 patients were included in the analysis. The 3-year local control, locoregional control, disease-free survival, and overall survival rates were 92%, 91%, 80%, and 87%, respectively. Feeding tubes were present in 55% of patients during treatment, but remained in only 1% 2 years following treatment. Conclusions This study confirms that IMRT yields excellent treatment outcomes for oropharyngeal carcinoma. Although acute toxicity remains a problem, late toxicity rates are low and long-term feeding tube dependence is rare compared with conventional radiation therapy. © 2013 Wiley Periodicals, Inc. Head Neck 35: 1796-1800, 2013 [ABSTRACT FROM AUTHOR]

Background Evolving epidemiology and improvements in locoregional therapy necessitate reassessment of the relationship between locoregional failure and distant metastasis in squamous cell carcinoma of the head and neck (SCCHN). Methods Retrospective assessments of factors associated with distant metastasis-free survival were made for 560 patients with SCCHN who received definitive radiotherapy (RT) +/− concurrent systemic therapy at our institution between 1995 and 2007. Results Fifty-six patients (10.0%) developed distant metastasis. Three-year actuarial locoregional control and distant metastasis-free survival were 72% and 87%, respectively. Multivariate analysis revealed N classification and locoregional failure as significant predictors of reduced distant metastasis-free survival ( p < .001). In patients with distant metastasis detected after locoregional failure, the mean interval between these events was 11.6 months. Conclusion Locoregional failure may play a causative role for distant metastasis in some patients with SCCHN, suggesting a need for continued focus on improving locoregional therapies. © 2012 Wiley Periodicals, Inc. Head Neck, 2013 [ABSTRACT FROM AUTHOR]

Background Altered fractionated radiotherapy (RT) has been shown to improve locoregional control (LRC) and overall survival (OS) in squamous cell cancer of the head and neck (SCCHN). We investigated patient outcomes using a new parameter: the average weekly dose (AWD). Methods The medical records of 601 patients who received definitive RT for SCCHN were reviewed. AWD was calculated by dividing the total dose in Gray (Gy) by overall treatment time in weeks, and assessed for predictive value. Results Various standard RT fractionation schedules were used. An AWD >10.0 Gy was associated with improved LRC at 2 years for patients treated with RT alone (80.9% vs 60.9%; p = .006), but not for those treated with concurrent chemoradiation (75.3% vs 77.3%; p = .77). Nonsignificant increases in late dysphagia were seen with AWD >10.0 Gy. Conclusion An AWD of >10 Gy was found to be beneficial for RT alone regimens but not chemoradiotherapy regimens. Head Neck, 2011 [ABSTRACT FROM AUTHOR]

Purpose: Intensification of radiotherapy and chemotherapy for head-and-neck cancer may lead to increased rates of dysphagia. Dosimetric predictors of objective findings of long-term dysphagia were sought. Methods and Materials: From an institutional database, 83 patients were identified who underwent definitive intensity-modulated radiotherapy for squamous cell carcinoma of the head and neck, after exclusion of those who were treated for a second or recurrent head-and-neck primary lesion, had locoregional recurrence at any time, had less than 12 months of follow-up, or had postoperative radiotherapy. Dosimetric parameters were analyzed relative to three objective endpoints as a surrogate for severe long-term dysphagia: percutaneous endoscopic gastrostomy (PEG) tube dependence at 12 months, aspiration on modified barium swallow, or pharyngoesophageal stricture requiring dilation. Results: Mean dose greater than 41 Gy and volume receiving 60 Gy (V60) greater than 24% to the larynx were significantly associated with PEG tube dependence and aspiration. V60 greater than 12% to the inferior pharyngeal constrictor was also significantly associated with increased PEG tube dependence and aspiration. V65 greater than 33% to the superior pharyngeal constrictor or greater than 75% to the middle pharyngeal constrictor was associated with pharyngoesophageal stricture requiring dilation. Conclusions: Doses to the larynx and pharyngeal constrictors predicted long-term swallowing complications, even when controlled for other clinical factors. The addition of these structures to intensity-modulated radiotherapy optimization may reduce the incidence of dysphagia, although cautious clinical validation is necessary. [Copyright &y& Elsevier]

Standard of care radiotherapy (RT) doses have been developed as a one-size-fits all approach designed to maximize tumor control rates across a population. Although this has led to high control rates for head and neck cancer with 66–70 Gy, this is done without considering patient heterogeneity. We present a framework to estimate a personalized RT dose for individual patients, based on pre- and early on-treatment tumor volume dynamics—a dynamics-adapted radiotherapy dose (DDARD). We also present the results of an in silico trial of this dose personalization using retrospective data from a combined cohort of n = 39 head and neck cancer patients from the Moffitt and MD Anderson Cancer Centers that received 66–70 Gy RT in 2–2.12 Gy weekday fractions. This trial was repeated constraining DDARD between (54, 82) Gy to test more moderate dose adjustment. DDARD was estimated to range from 8 to 186 Gy, and our in silico trial estimated that 77% of patients treated with standard of care were overdosed by an average dose of 39 Gy, and 23% underdosed by an average dose of 32 Gy. The in silico trial with constrained dose adjustment estimated that locoregional control could be improved by >10%. We demonstrated the feasibility of using early treatment tumor volume dynamics to inform dose personalization and stratification for dose escalation and de-escalation. These results demonstrate the potential to both de-escalate most patients, while still improving population-level control rates. [ABSTRACT FROM AUTHOR]

Purpose: Intensity modulated radiation therapy (IMRT) has been shown to significantly reduce dose to normal tissue while maintaining coverage of the clinical target volume (CTV) in patients with intact breast cancer. We compared delivery of whole breast irradiation utilizing three techniques: electronic tissue compensation (ECOMP), inverse-planned dynamic multileaf collimation IMRT (DMLC), and tomotherapy (TOMO). Patients and Methods: Ten patients with early stage, left-sided breast cancer were selected for planning. CTV was defined as breast encompassed in a standard tangent field minus the superficial 5 mm from the skin edge. Normal tissue contours included the heart, lungs, and contralateral breast. Plans included delivery of 45 Gy in 25 fractions and were normalized to ensure > or =95% coverage of the CTV. Isodose distributions and dose-volume histograms for CTV and normal tissue were compared between plans. The time it took to plan each patient excluding contouring, as well as number of monitor units (MUs) required to execute each plan were additionally tabulated. Results: The TOMO plans resulted in significantly greater heterogeneity (CTV V(115)) versus ECOMP (p = 0.0029). The ECOMP plans resulted in significantly lower doses to heart, lung, and contralateral breast when compared with TOMO plans. The ECOMP plans were generated in the shortest time (12 min) and resulted in the lowest number of MUs when compared with DMLC (p = 0.002, p < 0.0001) and TOMO (p = 0.0015, p < 0.0001). Conclusions: The ECOMP plans produced superior dose distributions in both the CTV and normal tissue when compared with TOMO or DMLC plans. In addition, ECOMP plans resulted in the lowest number of MUs and labor cost. [ABSTRACT FROM AUTHOR]

: PurposeTo evaluate the outcomes of patients with giant cell tumor of bone (GCTB) treated with radiotherapy (RT) with or without surgical resection.: Methods and materialsWe performed a retrospective review of the records from 25 consecutive patients with pathologically confirmed GCTB who had undergone RT between 1956 and 2000.: ResultsPatients ranged in age from 11 to 69 years (median 32); 16 were female and 9 were male. The anatomic distribution of lesions was as follows: cervical spine, 3; temporal bone, 1; thoracic or lumbar spine, 9; sacrum, 8; ilium, 1, and humerus, radius, and thumb metacarpal, 1 each. Tumors ranged in size from 2 to 20 cm (median 9.5) at their maximal dimension. Thirteen patients had been referred for RT for primary GCTB and 12 had been referred with locally recurrent disease after having undergone one or more other treatments. Fourteen patients had undergone RT for gross disease, and the remaining 11 had been treated with RT after gross total resection. In 10 of these 11 patients, the treatment margins were positive or uncertain. Radiation doses ranged from 25 to 65 Gy (median 46). At a median follow-up of 8.8 years (range 0.67–34), 7 patients had developed isolated local recurrence, 2 had developed isolated distant recurrence, and 3 had developed both. The actuarial 5-year overall and disease-free survival rate was 91% and 58%, respectively, and the actuarial 5-year local control and distant metastasis-free survival rate was 62% and 81%, respectively. Univariate analysis suggested that treatment for recurrent disease correlated with a lower disease-free survival rate (83% vs. 33%, p = 0.06), distant metastasis-free survival rate (100% vs. 64%, p = 0.08), and local control rate (83% vs. 42%, p = 0.08) at 5 years. Of the 12 cases of recurrence, 7 were ultimately successfully treated with additional salvage therapy. In 4 of these patients, salvage therapy included interferon-α2b.: ConclusionRT should be considered an adjuvant to surgery or as alternative therapy in cases of GCTB that are unresectable or in which excision would result in substantial functional deficits. When RT is used as primary therapy, the rate of local control seems to be satisfactory. In heavily pretreated patients, however, RT delivered as it was in this series can result in poor local control, and alternative therapies should be considered. [Copyright &y& Elsevier]

The increased incidence of human papillomavirus (HPV)-related cancers has motivated efforts to optimise treatment for these patients with excellent prognosis. Validation of surrogates for overall survival could expedite the investigation of new therapies. We sought to evaluate candidate intermediate clinical endpoints in trials assessing definitive treatment of p16-positive oropharyngeal cancer with chemotherapy or radiotherapy. We did a retrospective review of five multicentre, randomised trials (NRG/RTOG 9003, 0129, 0234, 0522, and 1016) that tested radiotherapy with or without chemotherapy in patients (aged ≥18 years) with p16-positive localised head or neck squamous-cell carcinomas. Eight intermediate clinical endpoints were considered as potential surrogates for overall survival: freedom from local progression, freedom from regional progression, freedom from distant metastasis, freedom from locoregional progression, freedom from any progression, locoregional progression-free survival, progression-free survival, and distant metastasis-free survival. We used a two-stage meta-analytical framework, which requires high correlation between the intermediate clinical endpoint and overall survival at the patient level (condition 1), and high correlation between the treatment effect on the intermediate clinical endpoint and the treatment effect on overall survival (condition 2). For both, an r2 greater than 0·7 was used as criteria for clinically relevant surrogacy. We analysed 1373 patients with oropharyngeal cancer from May 9, 2020, to Nov 22, 2023. 1231 (90%) of patients were men, 142 (10%) were women, and 1207 (88%) were White, with a median age of 57 years (IQR 51–62). Median follow-up was 4·2 years (3·1–5·1). For the first condition, correlating the intermediate clinical endpoints with overall survival at the individual and trial level, the three composite endpoints of locoregional progression-free survival (Kendall's τ 0·91 and r2 0·72), distant metastasis-free survival (Kendall's τ 0·93 and r2 0·83), and progression-free survival (Kendall's τ 0·88 and r2 0·70) were highly correlated with overall survival at the patient level and at the trial-group level. For the second condition, correlating treatment effects of the intermediate clinical endpoints and overall survival, the composite endpoints of locoregional progression-free survival (r2 0·88), distant metastasis-free survival (r2 0·96), and progression-free survival (r2 0·92) remained strong surrogates. Treatment effects on the remaining intermediate clinical endpoints were less strongly correlated with overall survival. We identified locoregional progression-free survival, distant metastasis-free survival, and progression-free survival as surrogates for overall survival in p16-positive oropharyngeal cancers treated with chemotherapy or radiotherapy, which could serve as clinical trial endpoints. NRG Oncology Operations, NRG Oncology SDMC, the National Cancer Institute, Eli Lilly, Aventis, and the University of Michigan. [ABSTRACT FROM AUTHOR]

Patients with locoregional recurrence of squamous cell carcinoma of the head and neck (SCCHN) have relatively poor outcomes; therefore, stereotactic body radiation therapy (SBRT) has been investigated for this patient population. We performed a phase 1 clinical trial to establish a maximum tolerated dose of SBRT with concurrent cisplatin in previously irradiated locoregional SCCHN. Patients with recurrent SCCHN who had previously undergone radiation therapy to doses ≥45 Gy to the area of recurrence ≥6 months before enrollment and who were not surgical candidates or refused surgery were eligible. SBRT was delivered every other day for 5 fractions. Starting dose level was 6 Gy × 5 fractions, followed by 7 Gy × 5 fractions and 8 Gy × 5 fractions. Chemotherapy consisted of cisplatin given before every SBRT fraction at a dose of 15 mg/m2. Patients were monitored for dose-limiting toxicities (DLT) that occurred within 3 months from the start of SBRT. Secondary endpoints included locoregional failure, distant metastasis, and overall survival. Twenty patients were enrolled, with 18 patients evaluable for endpoints. One patient at dose level 1 (30 Gy) died of unknown causes 2 weeks following completion of treatment. Therefore, an additional 3 patients were accrued to the 30-Gy dose level, with no further DLTs observed. Three patients were then accrued at dose level 2 (35 Gy) and 9 patients at dose level 3 (40 Gy) without DLTs. At a median follow-up of 9.5 months, cumulative incidence of locoregional failure at 2 years was 61% (95% confidence interval [CI], 12%-66%), cumulative incidence of distant metastasis was 11% (95% CI, 74%-100%) at 2 years, and overall survival was 22% (95% CI, 9%-53%) at 2 years. Concurrent cisplatin and reirradiation with an SBRT dose of ≤40 Gy was safe and feasible in patients with locoregionally recurrent or second primary SCCHN. [ABSTRACT FROM AUTHOR]

Purpose: The therapeutic ratio of reirradiation for recurrent or second primary (RSP) squamous carcinoma of the head and neck may be improved in the intensity modulated radiation therapy (IMRT) era. However, patient selection for reirradiation remains challenging. We performed a multi-institution cohort study to investigate modern outcomes after IMRT-based reirradiation and to identify prognostic subgroups.Patients and Methods: Patients with RSP squamous carcinoma originating in a previously irradiated field (≥40 Gy) who underwent reirradiation with IMRT (≥40 Gy re-IMRT) were included. Locoregional failure and late toxicity were calculated using the Gray competing risk method. Cox proportional hazards regression was used to identify factors associated with overall survival (OS). Factors associated with OS were entered into a recursive partitioning analysis (RPA) for OS.Results: From 7 institutions, 412 patients were included. The median dose of re-IMRT was 60 Gy, and the median time between RT courses was 2.4 years. Chemotherapy was used in 76% of patients. The rates of grade ≥3, grade ≥4, and grade 5 acute toxicities were 19%, 4.4%, and 1.2%, respectively. The 2-year cumulative incidence of grade ≥3 late toxicity adjusted for the competing risks of recurrence or death was 14.2%. RPA identified 3 prognostic subgroups with distinct and homogenous OS (P<.001): class I included patients >2 years from their initial course of RT with resected tumors (2-year OS, 61.9%); class II included patients >2 years with unresected tumors or those ≤2 years and without feeding tube or tracheostomy dependence (2-year OS, 40.0%), and the remaining patients formed class III (2-year OS, 16.8%). Fifty-nine percent of class III patients underwent postoperative re-irradiation.Conclusions: This study informs outcomes and expectations with IMRT-based reirradiation. The RPA classification identifies 3 distinct subgroups, which can guide patient selection for therapy and clinical trial design. RPA class III patients are not ideal candidates for protracted chemoradiation regardless of resection status. [ABSTRACT FROM AUTHOR]

Purpose: Two modern methods of reirradiation, intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT), are established for patients with recurrent or second primary squamous cell carcinoma of the head and neck (rSCCHN). We performed a retrospective multi-institutional analysis to compare methods.Methods and Materials: Data from patients with unresectable rSCCHN previously irradiated to ≥40 Gy who underwent reirradiation with IMRT or SBRT were collected from 8 institutions. First, the prognostic value of our IMRT-based recursive partitioning analysis (RPA) separating those patients with unresectable tumors with an intertreatment interval >2 years or those with ≤2 years and without feeding tube or tracheostomy dependence (class II) from other patients with unresected tumors (class III) was investigated among SBRT patients. Overall survival (OS) and locoregional failure were then compared between IMRT and SBRT by use of 2 methods to control for baseline differences: Cox regression weighted by the inverse probability of treatment and subset analysis by RPA classification.Results: The study included 414 patients with unresectable rSCCHN: 217 with IMRT and 197 with SBRT. The unadjusted 2-year OS rate was 35.4% for IMRT and 16.3% for SBRT (P<.01). Among SBRT patients, RPA classification retained an independent association with OS. On Cox regression weighted by the inverse probability of treatment, no significant differences in OS or locoregional failure between IMRT and SBRT were demonstrated. Analysis by RPA class showed similar OS between IMRT and SBRT for class III patients. In all class II patients, IMRT was associated with improved OS (P<.001). Further subset analysis demonstrated comparable OS when ≥35 Gy was delivered with SBRT to small tumor volumes. Acute grade ≥4 toxicity was greater in the IMRT group than in the SBRT group (5.1% vs 0.5%, P<.01), with no significant difference in late toxicity.Conclusions: Reirradiation both with SBRT and with IMRT appear relatively safe with favorable toxicity compared with historical studies. Outcomes vary by RPA class, which informs clinical trial design. Survival is poor in class III patients, and alternative strategies are needed. [ABSTRACT FROM AUTHOR]

The article reviews the book "Radiotherapy for Head & Neck Cancer: Indication & Techniques," by K. Kian Ang and Adam S. Garden.

Purpose: Recently, we developed radiosensitivity (RSI), a clinically validated molecular signature that estimates tumor radiosensitivity. In the present study, we tested whether integrating RSI with the molecular subtype refines the classification of local recurrence (LR) risk in breast cancer.Methods and Materials: RSI and molecular subtype were evaluated in 343 patients treated with breast-conserving therapy that included whole-breast radiation therapy with or without a tumor bed boost (dose range 45-72 Gy). The follow-up period for patients without recurrence was 10 years. The clinical endpoint was LR-free survival.Results: Although RSI did not uniformly predict for LR across the entire cohort, combining RSI and the molecular subtype identified a subpopulation with an increased risk of LR: triple negative (TN) and radioresistant (reference TN-radioresistant, hazard ratio [HR] 0.37, 95% confidence interval [CI] 0.15-0.92, P=.02). TN patients who were RSI-sensitive/intermediate had LR rates similar to those of luminal (LUM) patients (HR 0.86, 95% CI 0.47-1.57, P=.63). On multivariate analysis, combined RSI and molecular subtype (P=.004) and age (P=.001) were the most significant predictors of LR. In contrast, integrating RSI into the LUM subtype did not identify additional risk groups. We hypothesized that radiation dose escalation was affecting radioresistance in the LUM subtype and serving as a confounder. An increased radiation dose decreased LR only in the luminal-resistant (LUM-R) subset (HR 0.23, 95% CI 0.05-0.98, P=.03). On multivariate analysis, the radiation dose was an independent variable only in the LUMA/B-RR subset (HR 0.025, 95% CI 0.001-0.946, P=.046), along with age (P=.008), T stage (P=.004), and chemotherapy (P=.008).Conclusions: The combined molecular subtype-RSI identified a novel molecular subpopulation (TN and radioresistant) with an increased risk of LR after breast-conserving therapy. We propose that the combination of RSI and molecular subtype could be useful in guiding radiation therapy-based decisions in breast cancer. [ABSTRACT FROM AUTHOR]

Purpose: To model and predict individual patient responses to radiation therapy.Methods and Materials: We modeled tumor dynamics as logistic growth and the effect of radiation as a reduction in the tumor carrying capacity, motivated by the effect of radiation on the tumor microenvironment. The model was assessed on weekly tumor volume data collected for 2 independent cohorts of patients with head and neck cancer from the H. Lee Moffitt Cancer Center (MCC) and the MD Anderson Cancer Center (MDACC) who received 66 to 70 Gy in standard daily fractions or with accelerated fractionation. To predict response to radiation therapy for individual patients, we developed a new forecasting framework that combined the learned tumor growth rate and carrying capacity reduction fraction (δ) distribution with weekly measurements of tumor volume reduction for a given test patient to estimate δ, which was used to predict patient-specific outcomes.Results: The model fit data from MCC with high accuracy with patient-specific δ and a fixed tumor growth rate across all patients. The model fit data from an independent cohort from MDACC with comparable accuracy using the tumor growth rate learned from the MCC cohort, showing transferability of the growth rate. The forecasting framework predicted patient-specific outcomes with 76% sensitivity and 83% specificity for locoregional control and 68% sensitivity and 85% specificity for disease-free survival with the inclusion of 4 on-treatment tumor volume measurements.Conclusions: These results demonstrate that our simple mathematical model can describe a variety of tumor volume dynamics. Furthermore, combining historically observed patient responses with a few patient-specific tumor volume measurements allowed for the accurate prediction of patient outcomes, which may inform treatment adaptation and personalization. [ABSTRACT FROM AUTHOR]

Purpose: Dose-volume data for injury to carotid artery and other major vessels in stereotactic body radiation therapy (SBRT)/SABR head and neck reirradiation were reviewed, modeled, and summarized.Methods and Materials: A PubMed search of the English-language literature (stereotactic and carotid and radiation) in April 2018 found 238 major vessel maximum point doses in 6 articles that were pooled for logistic modeling. Two subsequent studies with dose-volume major vessel data were modeled separately for comparison. Attempts were made to separate carotid blowout syndrome from other bleeding events (BE) in the analysis, but we acknowledge that all except 1 data set has some element of BE interspersed.Results: Prior radiation therapy (RT) dose was not uniformly reported per patient in the studies included, but a course on the order of conventionally fractionated 70 Gy was considered for the purposes of the analysis (with an approximately ≥6-month estimated interval between prior and subsequent treatment in most cases). Factors likely associated with reduced risk of BE include nonconsecutive daily treatment, lower extent of circumferential tumor involvement around the vessel, and no surgical manipulation before or after SBRT.Conclusions: Initial data pooling for reirradiation involving the carotid artery resulted in 3 preliminary models compared in this Hypofractionated Treatment Effects in the Clinic (HyTEC) report. More recent experiences with alternating fractionation schedules and additional risk-reduction strategies are also presented. Complications data for the most critical structures such as spinal cord and carotid artery are so limited that they cannot be viewed as strong conclusions of probability of risk, but rather, as a general guideline for consideration. There is a great need for better reporting standards as noted in the High Dose per Fraction, Hypofractionated Treatment Effects in the Clinic introductory paper. [ABSTRACT FROM AUTHOR]

Purpose: Stereotactic body radiation therapy (SBRT) has emerged as a viable reirradiation strategy for locally recurrent previously-irradiated head and neck cancer. Doses in the literature have varied, which challenges clinical application of SBRT as well as clinical trial design.Material& Methods: A working group was formed through the American Association of Physicists in Medicine to study tumor control probabilities for SBRT in head and neck cancer. We herein present a systematic review of the available literature addressing the dose/volume data for tumor control probability with SBRT in patients with locally recurrent previously-irradiated head and neck cancer. Dose-response models are generated that present tumor control probability as a function of dose.Results: Data from more than 300 cases in 8 publications suggest that there is a dose-response relationship, with superior local control and possibly improved overall survival for doses of 35 to 45 Gy (in 5 fractions) compared with <30 Gy.Conclusion: Stereotactic body radiation therapy doses equivalent to 5-fraction doses of 40 to 50 Gy are suggested for retreatment. [ABSTRACT FROM AUTHOR]

Because of the unprecedented disruption of health care services caused by the COVID-19 pandemic, the American Society of Radiation Oncology (ASTRO) and the European Society for Radiotherapy and Oncology (ESTRO) identified an urgent need to issue practice recommendations for radiation oncologists treating head and neck cancer (HNC) in a time of limited resources and heightened risk for patients and staff. A panel of international experts from ASTRO, ESTRO, and select Asia-Pacific countries completed a modified rapid Delphi process. Topics and questions were presented to the group, and subsequent questions were developed from iterative feedback. Each survey was open online for 24 hours, and successive rounds started within 24 hours of the previous round. The chosen cutoffs for strong agreement (≥80%) and agreement (≥66%) were extrapolated from the RAND methodology. Two pandemic scenarios, early (risk mitigation) and late (severely reduced radiation therapy resources), were evaluated. The panel developed treatment recommendations for 5 HNC cases. In total, 29 of 31 of those invited (94%) accepted, and after a replacement 30 of 30 completed all 3 surveys (100% response rate). There was agreement or strong agreement across a number of practice areas, including treatment prioritization, whether to delay initiation or interrupt radiation therapy for intercurrent SARS-CoV-2 infection, approaches to treatment (radiation dose-fractionation schedules and use of chemotherapy in each pandemic scenario), management of surgical cases in event of operating room closures, and recommended adjustments to outpatient clinic appointments and supportive care. This urgent practice recommendation was issued in the knowledge of the very difficult circumstances in which our patients find themselves at present, navigating strained health care systems functioning with limited resources and at heightened risk to their health during the COVID-19 pandemic. The aim of this consensus statement is to ensure high-quality HNC treatments continue, to save lives and for symptomatic benefit. [ABSTRACT FROM AUTHOR]

Purpose: Because of the unprecedented disruption of health care services caused by the COVID-19 pandemic, the American Society of Radiation Oncology (ASTRO) and the European Society for Radiotherapy and Oncology (ESTRO) identified an urgent need to issue practice recommendations for radiation oncologists treating head and neck cancer (HNC) in a time of limited resources and heightened risk for patients and staff.Methods and Materials: A panel of international experts from ASTRO, ESTRO, and select Asia-Pacific countries completed a modified rapid Delphi process. Topics and questions were presented to the group, and subsequent questions were developed from iterative feedback. Each survey was open online for 24 hours, and successive rounds started within 24 hours of the previous round. The chosen cutoffs for strong agreement (≥80%) and agreement (≥66%) were extrapolated from the RAND methodology. Two pandemic scenarios, early (risk mitigation) and late (severely reduced radiation therapy resources), were evaluated. The panel developed treatment recommendations for 5 HNC cases.Results: In total, 29 of 31 of those invited (94%) accepted, and after a replacement 30 of 30 completed all 3 surveys (100% response rate). There was agreement or strong agreement across a number of practice areas, including treatment prioritization, whether to delay initiation or interrupt radiation therapy for intercurrent SARS-CoV-2 infection, approaches to treatment (radiation dose-fractionation schedules and use of chemotherapy in each pandemic scenario), management of surgical cases in event of operating room closures, and recommended adjustments to outpatient clinic appointments and supportive care.Conclusions: This urgent practice recommendation was issued in the knowledge of the very difficult circumstances in which our patients find themselves at present, navigating strained health care systems functioning with limited resources and at heightened risk to their health during the COVID-19 pandemic. The aim of this consensus statement is to ensure high-quality HNC treatments continue, to save lives and for symptomatic benefit. [ABSTRACT FROM AUTHOR]

Background: Despite its common use in cancer treatment, radiotherapy has not yet entered the era of precision medicine, and there have been no approaches to adjust dose based on biological differences between or within tumours. We aimed to assess whether a patient-specific molecular signature of radiation sensitivity could be used to identify the optimum radiotherapy dose.Methods: We used the gene-expression-based radiation-sensitivity index and the linear quadratic model to derive the genomic-adjusted radiation dose (GARD). A high GARD value predicts for high therapeutic effect for radiotherapy; which we postulate would relate to clinical outcome. Using data from the prospective, observational Total Cancer Care (TCC) protocol, we calculated GARD for primary tumours from 20 disease sites treated using standard radiotherapy doses for each disease type. We also used multivariable Cox modelling to assess whether GARD was independently associated with clinical outcome in five clinical cohorts: Erasmus Breast Cancer Cohort (n=263); Karolinska Breast Cancer Cohort (n=77); Moffitt Lung Cancer Cohort (n=60); Moffitt Pancreas Cancer Cohort (n=40); and The Cancer Genome Atlas Glioblastoma Patient Cohort (n=98).Findings: We calculated GARD for 8271 tissue samples from the TCC cohort. There was a wide range of GARD values (range 1·66-172·4) across the TCC cohort despite assignment of uniform radiotherapy doses within disease types. Median GARD values were lowest for gliomas and sarcomas and highest for cervical cancer and oropharyngeal head and neck cancer. There was a wide range of GARD values within tumour type groups. GARD independently predicted clinical outcome in breast cancer, lung cancer, glioblastoma, and pancreatic cancer. In the Erasmus Breast Cancer Cohort, 5-year distant-metastasis-free survival was longer in patients with high GARD values than in those with low GARD values (hazard ratio 2·11, 95% 1·13-3·94, p=0·018).Interpretation: A GARD-based clinical model could allow the individualisation of radiotherapy dose to tumour radiosensitivity and could provide a framework to design genomically-guided clinical trials in radiation oncology.Funding: None. [ABSTRACT FROM AUTHOR]

Purpose: We conducted a phase II multicenter study evaluating Caphosol in patients receiving head and neck radiation (H/N RT) +/- chemotherapy or biologic sensitizer. Materials/Methods: The primary endpoint of the study tested the rate of functional mucositis (WHO grade > or equal to 2) with the hypothesis that <75% of patients would develop > or equal to 2 mucositis with Caphosol compared with a historical rate of >90%. New methods were applied with higher than historic rigor. 5 Institutions were included in this study: Moffitt Cancer Center (MCC), MD Anderson Cancer Center (MDACC), Duke University Cancer Center (DUCC), University of Florida (UF) and Temple University Cancer Center (TUCC). Caphosol was taken by patients at least 4 times a day and up to 10 times per day commencing with day 1 of RT and for a total duration of 8weeks after completion of RT. Detailed questionnaires were completed weekly by patients and a unique algorithm was used to generate the WHO grade of mucositis. Results: 98 Patients were enrolled in the study. 59/98 (60%) patients were evaluable for the primary endpoint giving us 80% power. All evaluable patients experienced WHO grade > or equal to 2 mucositis and the trial failed to reject the null hypothesis. > or equal to 2 mucositis rates at weeks 2, 4, 6, 11 and 15 were as follows: 45%, 90%, 98%, 71%, 50%. Conclusion: We were unable to demonstrate that Caphosol significantly reduced WHO grade 2 or higher mucositis below a 90% historic rate. We are not surprised with this finding given our rigorous methodology in grading. [ABSTRACT FROM AUTHOR]

Objectives: To explore the influence of treatment package time(TPT) in high-risk oral cavity squamous cell carcinoma(OCSCC) receiving adjuvant radiotherapy with concurrent chemotherapy(CRT).Materials and Methods: We queried our multi-institutional OCSCC collaborative database for cases diagnosed between 2005 and 2015 who underwent surgery followed by adjuvant CRT. All patients had high-risk features: extranodal extension(ENE) and/or positive surgical margin(PM). TPT was days between surgery to last radiotherapy fraction. Kaplan-Meier curves, log-rank p-values and multivariate analysis(MVA) were used to investigate the impact of TPT on overall(OS), disease-free(DFS), locoregional failure-free(LRFS) and distant metastases-free(DMFS) survival.Results: We identified 187 cases: median age 58 (range, 24-87 years), males 66%, and ever smokers 69%. ENE and PM were detected in 85% and 32%, and oral tongue and floor of the mouth constituted 49% and 18%, respectively. Median radiotherapy and cisplatin doses received were 66 Gy and 200 mg/m2. Overall, median TPT was 98 (range, 63-162 days). OS was worse for TPT > 90-days (n = 134) than TPT ≤ 90 (n = 53) at two-(65% vs. 71%) and five-years (45% vs. 62%); p = 0.05, with similar results for DFS. No influence on LRFS or DMFS was noted. More lymph nodes(LN) dissected(P = 0.039), T3-4 disease(P = 0.017), and unplanned reoperations(P = 0.037) occurred with TPT > 90-days. On MVA, TPT in 10-day increments was independently detrimental for OS (Hazard Ratio: 1.14; 95 %Confidence Interval [1-1.28]; P = 0.043), perineural invasion, age and positive LN (p < 0.05 for all).Conclusion: In one of the largest multi-institutional cohorts, TPT > 90-days predicted worse OS for high-risk OCSCC receiving adjuvant CRT. All efforts are needed to optimize perioperative care and baseline conditions for favorable outcomes. [ABSTRACT FROM AUTHOR]