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Abstract Background and purpose Defining margins around the Gross Tumour Volume (GTV) to create a Clinical Target Volume (CTV) for head and neck cancer radiotherapy has traditionally been based on presumed knowledge of anatomical routes of spread. However, using a concentric geometric expansion around the GTV may be more reproducible. The purpose of this study was to analyse the inter-observer consistency of geometric CTV delineation with adaptation for anatomical boundaries versus anatomically defined CTVs. Material and methods Radiation oncologists at four Danish cancer centres delineated high, intermediate and elective dose CTVs (CTV1, CTV2 and CTV3, respectively) in a patient-case template (stage IV squamous cell carcinoma of the oropharynx), first using mainly anatomical margins (original standard) and then using concentric geometric expansion (new standard). Each centre made a dummy-run radiotherapy plan based on the delineated CTVs. The difference between the CTV contours and the radiotherapy plans was evaluated across the centres. Results Anatomy-based contours were significantly more heterogenous and showed larger volume differences between centres than geometric margins. Dice similarity coefficient increased by 0.29 and mean surface distance decreased by 4 mm for CTV1. Use of consistent CTV volumes resulted in more consistent irradiated volumes between centres. Conclusion Introduction of geometric margins resulted in more uniform CTV1 and CTV2 delineation. Geometric CTV expansion was easier, left less room for misinterpretation, and resulted in more uniform treatment plans with similar irradiated high and intermediate dose volumes across all centres. [ABSTRACT FROM AUTHOR]

Purpose To describe the pattern of failure in a national consecutive cohort of patients with glottic squamous cell carcinomas (SCC) treated with primary radiotherapy (RT) with curative intent over a 41-year period. Materials and methods All patients undergoing curative treatment for a glottic SCC diagnosed in Denmark between 1971 and 2011 were included and followed from the first contact with the oncology center to death or February 15, 2015. Results 5001 patients were identified of whom 98% had primary RT. The median follow-up was 9.1 years/5.7 years (patients alive/patients who died). Ten patients were lost to follow-up. In total 1511 failures were observed; of these 93%, 11% and 5% included T site, N site, and M site, respectively. For patients diagnosed in the 70s and the 00s, respectively, the five-year incidences were: local failure (32% vs 19%), loco-regional failure (34% vs 21%), laryngectomy (26% vs 10%), laryngectomy-free survival (48% vs 62%), disease-free survival (62% vs 68%), and overall survival (62% vs 68%). The five-year incidence of ultimate failure (13–16%) remained statistically unchanged. Conclusion From the 70s to the 00s a continually improving primary disease-control was observed with a concurrent decrease in the incidence of laryngectomy. The survival rate was significantly higher in the 00s compared to the previous three decades. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: Hypoxia is a cause of resistance to radiotherapy, especially in patients with head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to evaluate 18F-fluoroazomycin arabinoside (FAZA) positron emission tomography (PET)/computed tomography (CT) hypoxia imaging as a prognostic factor in HNSCC patients receiving radiotherapy. Material and methods: Forty patients with HNSCC treated with radiotherapy (66–76Gy) were included. Static FAZA PET/CT imaging 2h post injection was conducted prior to irradiation. The hypoxic volume (HV) was delineated using a tumor-to-muscle value ⩾1.4. In 13 patients, a repetitive FAZA PET/CT scan was conducted during the radiotherapy treatment. Results: A hypoxic volume could be identified in 25 (63%) of the 40 tumors. FAZA PET HV varied considerably with a range from 0.0 to 30.9 (median: 0.3) cm3. The Tmax/Mmed ranged from 1.1 to 2.9 (median: 1.5). The distribution of hypoxia among the Human Papillomavirus (HPV) positive (12/16) and negative (13/24) tumors was not significant different. In the FAZA PET/CT scans performed during radiotherapy, hypoxia could be detected in six of the 13 patients. For these six patients the location of HV remained stable in location during radiotherapy treatment, though the size of the HV decreased. In 30 patients a positive correlation was detected between maximum FAZA uptake in the primary tumor and the lymph node. During a median follow up of 19months a significant difference in disease free survival rate with 93% for patients with non hypoxic tumors and 60% for patients with hypoxic tumors could be detected. Conclusion: This study emphasizes the role of FAZA PET/CT imaging as a suitable assay with prognostic potential for detection of hypoxia in HNSCC. [Copyright &y& Elsevier]

• OS of larynx cancer patients treated at Odense DK, Manchester UK and Liverpool AUS is driven by tumour volume and PS. • Federated learning can be used to create survival models without patient-sensitive data leaving the individual institutions. • The baseline hazards of the three institutions are similar, indicating the GTV volume and PS explain the cohort differences. • Smoking during treatment has the same risk profile as a ten year older patient not smoking. Federated learning has the potential to perfrom analysis on decentralised data; however, there are some obstacles to survival analyses as there is a risk of data leakage. This study demonstrates how to perform a stratified Cox regression survival analysis specifically designed to avoid data leakage using federated learning on larynx cancer patients from centres in three different countries. Data were obtained from 1821 larynx cancer patients treated with radiotherapy in three centres. Tumour volume was available for all 786 of the included patients. Parameter selection among eleven clinical and radiotherapy parameters were performed using best subset selection and cross-validation through the federated learning system, AusCAT. After parameter selection, β regression coefficients were estimated using bootstrap. Calibration plots were generated at 2 and 5-years survival, and inner and outer risk groups' Kaplan-Meier curves were compared to the Cox model prediction. The best performing Cox model included log(GTV), performance status, age, smoking, haemoglobin and N-classification; however, the simplest model with similar statistical prediction power included log(GTV) and performance status only. The Harrell C-indices for the simplest model were for Odense, Christie and Liverpool 0.75[0.71–0.78], 0.65[0.59–0.71], and 0.69[0.59–0.77], respectively. The values are slightly higher for the full model with C-index 0.77[0.74–0.80], 0.67[0.62–0.73] and 0.71[0.61–0.80], respectively. Smoking during treatment has the same hazard as a ten-years older nonsmoking patient. Without any patient-specific data leaving the hospitals, a stratified Cox regression model based on data from centres in three countries was developed without data leakage risks. The overall survival model is primarily driven by tumour volume and performance status. [ABSTRACT FROM AUTHOR]

• Open-source distributed learning can validate survival models without sharing patient-sensitive data. • The MAASTRO model can predict the survival of larynx cancer patients treated at Odense and The Christie. • The absolute survival prediction requires a recalibration factor of 0.78 to predict survival accurately. • The baseline hazard between the two institutions is significantly different. • Additional parameters are needed to improve survival prediction. Prediction models are useful to design personalised treatment. However, safe and effective implementation relies on external validation. Retrospective data are available in many institutions, but sharing between institutions can be challenging due to patient data sensitivity and governance or legal barriers. This study validates a larynx cancer survival model performed using distributed learning without any sensitive data leaving the institution. Open-source distributed learning software based on a stratified Cox proportional hazard model was developed and used to validate the Egelmeer et al. MAASTRO survival model across two hospitals in two countries. The validation optimised a single scaling parameter multiplied by the original predicted prognostic index. All analyses and figures were based on the distributed system, ensuring no information leakage from the individual centres. All applied software is provided as freeware to facilitate distributed learning in other institutions. 1745 patients received radiotherapy for larynx cancer in the two centres from Jan 2005 to Dec 2018. Limiting to a maximum of one missing value in the parameters of the survival model reduced the cohort to 1095 patients. The Harrell C-index was 0.74 (CI95%, 0.71–0.76) and 0.70 (0.66–0.75) for the two centres. However, the model needed a scaling update. In addition, it was found that survival predictions of patients undergoing hypofractionation were less precise. Open-source distributed learning software was able to validate, and suggest a minor update to the original survival model without central access to patient sensitive information. Even without the update, the original MAASTRO survival model of Egelmeer et al. performed reasonably well, providing similar results in this validation as in its original validation [ABSTRACT FROM AUTHOR]

Background and purpose HPV is found in head and neck cancer from all sites with a higher prevalence in oropharynx cancer (OPC) compared to non-OPC. HPV/p16-status has a significant impact on radiotherapy (RT) outcome in advanced OPC, but less is known about the influence in non-OPC. We analyzed HPV-associated p16-expression in a cohort of patients with stage III–IV pharynx and larynx cancer treated with primary, curatively intended (chemo-)RT, aiming to test the hypothesis that the impact of HPV/p16 also extends to tumors of non-oropharyngeal origin. Material and methods 1294 patients enrolled in previously conducted DAHANCA-trials between 1992 and 2012 were identified. Tumors were evaluated by p16-immunohistochemistry and classified as positive in case of staining in >70% of tumors cells. Results Thirty-eight percent (490/1294) of the tumors were p16-positive with a significantly higher frequency in OPC (425/815) than in non-OPC (65/479), p < .0001. In OPC p16-positivity significantly improved loco-regional control (LRC) (adjusted HR [95% CI]: 0.43 [0.32–0.57]), event-free survival (EFS) (HR 0.44 [0.35–0.56]), and overall survival (OS) (HR: 0.38 [0.29–0.49]), respectively, compared with p16-negativity. In non-OPC no prognostic impact of p16-status was found for either endpoint: LRC (HR: 1.13 [0.75–1.70]), EFS (HR: 1.06 [0.76–1.47]), and OS (HR: 0.82 [0.59–1.16]). Conclusions The independent influence of HPV-associated p16-expression in advanced OPC treated with primary RT was confirmed. However, RT-outcome in the group of non-OPC did not differ by tumor p16-status, indicating that the prognostic impact may be restricted to OPC only. [ABSTRACT FROM AUTHOR]

• Visualising 3D mean standard deviation in contouring emphasizes areas of OARs with the highest interoberver disagreements. • Areas with high interobserver variation should be further discussed to clarify clinical guidelines. • Even between experts, there is some remaining variation which could serve as comparator for automated delineation tools. [ABSTRACT FROM AUTHOR]

• Application of consensus guidelines results in increased consistency in high-dose CTV1. • A 3-year local control is not influenced by GTV-CTV1 margin. • Half of analysable radiology-verified local recurrences are in primary GTV. • 76 % of radiology-verified local recurrences are inside CTV1 using 5 mm margin consensus. Treatment planning using a five-millimetre geometrical margin from GTV to high-dose CTV (CTV1) has been used in DAHANCA treatment centres since 2013. We aimed to evaluate changes in CTV1 volumes, local control (LC), and recurrence pattern after the implementation of five-millimetre geometrical margins nationally. 1,948 patients with pharyngeal, and laryngeal squamous cell carcinomas completed definitive IMRT-based treatment in 2010–2012 and 2013–2015 in three centres. The patient-specific margin was calculated as median surface distance from primary tumour GTV (GTV-T) to CTV1. Radiologically verified local recurrences were analysed using a centre of mass (COM) of the delineated recurrence volume, measuring the shortest distance between COM to GTV-T and CTV1 boundaries. Median GTV-CTV1 was 0.9 (0.0–0.97) and 0.47 cm (0.4–0.5) for 2010–2012 and 2013–2015, respectively. Median CTV1 changed in three centres from 76, 28, 42 cm3 to 61, 53, 62 cm3 for 2010–2012 and 2013–2015, respectively. Local failures occurred at 247 patients during first three years after radiotherapy. The 3-year LC rate for 2010–2012 and 2013–2015 was 0.84 and 0.87 (p = 0.06). Out of 146 radiology-verified analysable local recurrences, 102 (69.9%) were inside the CTV1. In 74.6% and 91% of cases, the LRs were covered by 95% isodose in 2010–2012 and 2013–2015, respectively. DAHANCA radiotherapy guidelines based on a geometrically generated isotropic CTV1 margin led to less variation in treatment volumes and between centres than previous guidelines. The transition towards consensus GTV-CTV1 margins did not influence local tumour control. The majority of local recurrences were inside CTV1 and covered by the prescription dose. [ABSTRACT FROM AUTHOR]

Abstract: Background: The quality of Volumetric Modulated Arc Therapy (VMAT) plans is highly dependent on the performance of the optimization algorithm used. Recently new algorithms have become available which are capable of generating VMAT plans for Elekta accelerators. The VMAT algorithm in Pinnacle3® is named SmartArc and its capability to generate treatment plans for head and neck cancer was tested. Methods: Twenty-five patients with oropharyngeal or hypopharyngeal carcinoma, previously treated with IMRT by means of Pinnacle3® and Elekta accelerators, were replanned with single arc VMAT. The VMAT planning objectives were to achieve clinical target coverage and sparing of the organs at risk (OAR). Comparison with the original clinically used IMRT was made by evaluating (1) dose–volume histograms (DVHs) for PTVs, (2) DVHs for OARs, (3) delivery time and monitor units (MU), and (4) treatment accuracy. Results: Equivalent or superior target coverage and sparing of OARs were achieved with VMAT compared to IMRT. Volumes in the healthy tissues receiving between 17.3Gy and 49.4Gy were significantly reduced and the conformity (CI95%) of the elective PTV was improved from 1.7 with IMRT to 1.6 with VMAT. Compared to step-and-shoot IMRT, VMAT reduced the number of MUs by 8.5% to 460±63MUs per fraction, and delivered on an Elekta Synergy accelerator, the treatment time was on average reduced by 35% to 241±16s. In Delta4® measurements of the VMAT treatments, 99.6±0.5% of the detector points passed a 3mm and 3% gamma criterion, identical to the results of IMRT. Conclusions: The target coverages obtained in the IMRT and VMAT plans were found to be very similar. SmartArc generated single arc VMAT plans with equivalent or better target coverage and sparing of OARs compared to IMRT, while both delivery time and MUs were decreased. Very good dose accuracy results were obtained delivering the plans on an Elekta accelerator. [Copyright &y& Elsevier]

• The only RCT following the widely accepted ORNguideline published by Marx in1983. • HBO seems to have a positive influence on the curation of osteoradionecrosis. • HBO shows a positive trend on quality of life, swallowing and ADL in HNC patients. • Only ORN of the mandible, diagnosed according to strict criteria, was included. Osteoradionecrosis (ORN) of the mandible is a serious complication of head and neck radiotherapy. This study aims to investigate the effect of hyperbaric oxygen (HBO) treatment on ORN in two randomized, controlled multicentre trials. Patients with ORN with indication for surgical treatment were randomised to either group 1: surgical removal of necrotic mandibular bone supplemented by 30 pre- and 10 postoperative HBO exposures at 243 kPa for 90 min each, or group 2: surgical removal of necrotic bone only. Primary outcome was healing of ORN one year after surgery evaluated by a clinically adjusted version of the Common Toxicity Criteria of Adverse Events (CTCAE) v 3.0. Secondary outcomes included xerostomia, unstimulated and stimulated whole salivation rates, trismus, dysphagia, pain, Activities of Daily Living (ADL) and quality of life according to EORTC. Data were combined from two separate trials. Ninety-seven were enrolled and 65 were eligible for the intent-to-treat analysis. The 33% drop-out was equally distributed between groups. In group 1, 70% (21/30) healed compared to 51% (18/35) in group 2. HBO was associated with an increased chance of healing independent of baseline ORN grade or smoking status as well as improved xerostomia, unstimulated whole salivary flow rate, and dysphagia. Due to insufficient recruitment, none of the endpoints reached a statistically significant difference between groups. ADL data could only be obtained from 50 patients. Hyperbaric oxygen did not significantly improve the healing outcome of osteoradionecrosis after surgical removal of necrotic bone as compared to standard care (70% vs. 51%). This effect is not statistically significant due to the fact that the study was underpowered and is therefore prone to type II error. [ABSTRACT FROM AUTHOR]

• Tumor volume, SLC3A2 and CD44 are prognostic for high-dose failure in HNSCC. • SLC3A2 is a biomarker for high-dose failure in (C-)RT for p16 + oropharyngeal SCC. • Tumor volume is the main driver for high-dose failure in p16- HNSCC. • Tumor hypoxia was not prognostic in patients treated with concomitant nimorazole. Reliable and accessible biomarkers for patients with Head and Neck Squamous Cell Carcinoma (HNSCC) are warranted for biologically driven radiotherapy (RT). This study aimed to investigate the prognostic value of putative cancer stem cell (CSC) markers, hypoxia, and tumor volume using loco-regional high-dose failure (HDF) as endpoint. Tumor tissue was retrieved from patients treated with primary chemo-(C-)RT and nimorazole for HNSCC in the Danish Head and Neck Cancer Study Group (DAHANCA) 19 study. Tumor volume, hypoxic classification, and expression of CSC markers CD44, SLC3A2 , and MET were analyzed. For patients with eligible data on all parameters (n = 340), the risk of HDF following primary chemo-(C-)RT were analyzed by these biomarkers as a whole and stratified for p16-positive oropharynx (p16 + OPSCC) vs p16-negative (p16-) tumors (oral cavity, p16- oropharynx, hypopharynx and larynx). Higher risk of HDF was seen for patients with larger primary and nodal volume (>25 cm3, Hazard Ratio (HR): 3.00 [95 % CI: 1.73–5.18]), high SLC3A2 (HR: 2.99 [1.28–6.99]), CD44 (>30 % positive, HR: 2.29 [1.05–5.00]), and p16- tumors (HR: 2.53 [1.05–6.11]). p16- tumors had a higher CSC marker expression than p16 + OPSCC. The factors associated with the highest risk of HDF were larger volume (HR: 3.29 [1.79–6.04]) for p16- tumors (n = 178) and high SLC3A2 (HR: 6.19 [1.58–24.23]) for p16 + OPSCC (n = 162). Tumor volume, p16, and CSC markers are potential biomarkers for HDF for patients with HNSCC treated with (C-)RT. Lower expression of CSC in p16 + OPSCC may contribute to better tumor control. [ABSTRACT FROM AUTHOR]

• 18F-FAZA imaging was used in a prospective trial of 38 HNSCC patients completing radiotherapy. • Within 5 years of follow-up, nine locoregional treatment failures were observed. • A high tumor-muscle ratio of tracer uptake (TMR ≥1.6) was associated with a higher risk of locoregional failure. • This association remained significant, when accounting for HPV/p16-positivity. • FAZA PET likely identifies cases, where treatment intensification is indicated. Hypoxic tumor volumes can be visualized with 18F-FAZA PET/CT. In head and neck squamous cell carcinoma (HNSCC), hypoxia is important for the clinical outcome after primary radiotherapy (RT). The outcome is furthermore heavily influenced by the HPV/p16-positivity of oropharyngeal tumors (OPCp16+ tumors). The study purposes were (1) to report on locoregional failures within five years after primary RT in a prospective cohort stratified by both HPV/p16-status and PET hypoxia and (2) to characterize the failure site and the spatial association to PET hypoxia. From 2009 to 2011, 38 patients with non-metastatic SCC of the larynx, oro-, hypo- and nasopharynx completing primary RT were included in the prospective DAHANCA 24 trial (NCT01017224). Fifteen patients had OPCp16+ tumors. All were imaged with a static FAZA PET/CT prior to treatment. The hypoxia threshold was determined by a tumor-to-muscle ratio (TMR) of 1.6. Recurrences were documented histologically. Imaging of the recurrence was deformable fused with the pre-treatment FAZA PET/CT. The spatial information of recurrence- and hypoxic volumes were compared visually. Sixteen patients had more hypoxic tumors (high tracer uptake, TMR ≥1.6) before treatment (42%). With a median follow-up of 7.8 years, nine locoregional recurrences were observed, of which seven were in patients with high-uptake tumors (44% and 9%, respectively, HR 5.8 [1.2–28.2]). The risk of locoregional recurrence was highest among patients with more hypoxic, non-OPCp16+ tumors (57% [21–94%]), with a risk difference of 45% [4–86%], when comparing to less hypoxic, non-OPCp16+ tumors. Eight patients had sufficient imaging of the recurrence for co-registration with the FAZA PET/CT. Six had hypoxic primary tumors, and in two, the recurrence was overlapping the baseline hypoxic subvolume. HNSCC demonstrating a TMR ≥1.6 at baseline is significantly associated with treatment failure after primary RT. In addition to HPV/p16-status, FAZA PET/CT has potential for the selection of tumors requiring treatment intensification. [ABSTRACT FROM AUTHOR]

• Late toxicity is substantial in all examined organs at risk. • Associations between dose to the optic nerve and ocular toxicity was present. • Across all examinations, 74% had late toxicity in more than one organ. • The severity of toxicity increased with increasing number of organs affected. To evaluate the occurrence of late toxicity after curatively intended intensity modulated radiotherapy (IMRT) for sinonasal cancer and assess dose–response associations. Patients treated with IMRT in 2008–2016 were included. Cross sectional examinations of toxicity from the optic pathway, the brain, the pituitary gland and the nose were performed along with quality of life – (QoL) and dose–response analyses. Twenty-seven patients were enrolled; median age was 67 years (range 47–83). Five patients (19%) had radiation-related ocular toxicity. The risk of visual acuity impairment increased with increasing dose (grade 2 odds ration (OR) 1.12, p = 0.01; grade 3 OR 1.14, p = 0.02) and dose constraint violations (grade 2, OR = 21, p < 0.01; grade 3, OR = 41, p < 0.01). Six patients (22%) exhibited evidence of radiation-related hypopituitarism, but no dose–response association was detected. Seventeen patients (63%) had impaired olfactory function. The risk of olfactory impairment increased with higher stage (OR = 3.32, p = 0.03). Three patients (11%) had structural abnormalities in irradiated areas of the brain, and impaired cognitive function was present in 17 patients (63%). Cognitive, physical, role functioning as well as fatigue and insomnia were affected the most in QOL analyses. Fifteen patients (56%) had grade 2 radiation-related impairment in at least one organ. Grade 3 toxicity was only present in patients with toxicities in >3 organs and in patients initially treated for T4 tumours. Three patients (11%) had radiation-related impaired function in all examined OARs. Late toxicity after radiotherapy was substantial in all examined organs, with dose–response associations between visual acuity impairment and the optic nerve. The results have led to changed praxis for follow-up examinations in Denmark. [ABSTRACT FROM AUTHOR]

• The two most commonly used hypoxia PET tracers FMISO and FAZA can be analyzed jointly. • Hypoxia PET derived parameters delivered strong and independent prognostic value. • Hypoxia specific treatment did not improve outcome in exploratory post hoc analyses. Tumor hypoxia plays an important role in head and neck squamous cell carcinomas (HNSCC). Various positron emission tomography (PET) tracers promise non-invasive assessment of tumor hypoxia. So far, the applicability of hypoxia PET is hampered by monocentric imaging trials with few patients. Multicenter individual patient data based meta-analysis of the original PET data from four prospective imaging trials was performed. All patients had localized disease and were treated with curatively intended radio(-chemo)therapy. Hypoxia PET imaging was performed with 18F-Fluoromisonidazole (FMISO, 102 patients) or 18F-Fluoroazomycin-arabinoside (FAZA, 51 patients). Impact of hypoxia PET parameters on loco-regional control (LRC) and overall survival (OS) was analyzed by uni- and multivariable Cox regression. Baseline characteristics between participating centers differed significantly, especially regarding T stage (p < 0.001), tumor volume (p < 0.001) and p16 status (p = 0.009). The commonly used hypoxia parameters, maximal tumor-to-muscle ratio (TMR max) and hypoxic volume with 1.6 threshold (HV 1.6), showed a strong association with LRC (p = 0.001) and OS (p < 0.001). These findings were irrespective of the radiotracer and the same cut-off values could be applied for FMISO and FAZA (TMR max > 2.0 or HV 1.6 > 1.5 ml). The effect size of TMR max was similar for subgroups of patients defined by radiotracer, p16 status and FDG-PET parameters for LRC and OS, respectively. PET measured hypoxia is robust and has a strong impact on LRC and OS in HNSCC. The most commonly investigated tracers FMISO and FAZA can probably be used equivalently in multicenter trials. Optimal strategies to improve the dismal outcome of hypoxic tumors remain elusive. [ABSTRACT FROM AUTHOR]

• Desentralised plan comparison is robust; however, many aspects of treatment planning need to be validated. • Local plan comparison between protons and photons seems to overestimate the ΔNTCP slightly. • Target and OAR contouring differences play an important role in the robustness of the patient selection. Proton treatment can potentially spare patients with H&N cancer for substantial treatment-related toxicities. The current study investigated the reproducibility of a decentralised model-based selection of patients for a proton treatment study when the selection plans were compared to the clinical treatment plans performed at the proton centre. Sixty-three patients were selected for proton treatment in the six Danish Head and Neck Cancer (DAHANCA) centres. The patients were selected based on normal tissue complication probability (NTCP) estimated from local photon and proton treatment plans, which showed a ΔNTCP greater than 5%-point for either grade 2 + dysphagia or grade 2 + xerostomia at six months. The selection plans were compared to the clinical treatment plans performed at the proton centre. Of the 63 patients, 49 and 25 were selected based on an estimated benefit in risk of dysphagia and xerostomia, respectively. Eleven patients had a potential gain in both toxicities. The mean ΔNTCP changed from the local selection plan comparison to the clinical comparison from 6.9 to 5.3 %-points (p = 0.01) and 7.3 to 4.9 %-points (p = 0.03) for dysphagia and xerostomia, respectively. Volume differences in both CTV and OAR could add to the loss in ΔNTCP. 61 of the 63 clinical plans had a positive ΔNTCP, and 38 had a ΔNTCP of 5%-points for at least one of the two endpoints. A local treatment plan comparison can be used to select candidates for proton treatment. The local comparative proton plan overestimates the potential benefit of the clinical proton plan. Continuous quality assurance of the delineation procedures and planning is crucial in the subsequent randomised clinical trial setting. [ABSTRACT FROM AUTHOR]

Purpose To evaluate if correction of low hemoglobin (Hb) levels by means of darbepoetin alfa improves the outcomes of radiotherapy in patients with squamous cell carcinoma of the head and neck (HNSCC). Patients and methods Patients eligible for primary radiotherapy and who had Hb values below 14.0 g/dl were randomized to receive accelerated fractionated radiotherapy with or without darbepoetin alfa. Patients also received the hypoxic radiosensitizer nimorazole. Darbepoetin alfa was given weekly during radiotherapy or until the Hb value exceeded 15.5 g/dl. Results Following a planned interim analysis which showed inferiority of the experimental treatment the trial was stopped after inclusion of 522 patients (of a planned intake of 600). Of these, 513 were eligible for analysis (254 patients treated with darbepoetin alfa and 259 patients in the control group). Overall, the patients were distributed according to the stratification parameters (gender, T and N staging, tumor site). Treatment with darbepoetin alfa increased the Hb level to the planned value in 81% of the patients. The compliance was good without excess serious adverse events. The results showed a poorer outcome with a 5-year cumulative loco-regional failure rate of 47% vs. 34%, Hazard Ratio (HR): 1.53 [1.16–2.02], for the darbepoetin alfa vs. control arm, respectively. This was also seen for the endpoints of event-free survival (HR: 1.36 [1.09–1.69]), disease-specific death (HR: 1.43 [1.08–1.90]), and overall survival (HR: 1.30 [1.02–1.64]). There was no enhanced risk of cardio-vascular events observed in the experimental arm or any significant differences in acute or late radiation related morbidity. All univariate analyses were confirmed in a multivariate setting. Conclusion Correction of the Hb level with darbepoetin alfa during radiotherapy of patients with HNSCC resulted in a significantly poorer tumor control and survival. [ABSTRACT FROM AUTHOR]

Abstract Introduction The aim was to analyze position of CT-verified local recurrences (LR) and local control (LC) among three centers that used different GTV to CTV1 margins. Materials and methods In total, 1576 patients completing radical primary IMRT for larynx, pharynx, oral cavity HNSCC in three centers in Denmark between 2006 and 2012 were included. CT-verified LRs were analyzed as possible points of recurrence origin and compared between groups of small (0–2.5 mm), larger (>2.5 mm), and anatomical GTV-CTV1 margins. The recurrence point's position relative to the GTV and 95% prescription dose was evaluated. Overall local control rate was evaluated using Cox uni- and multi-variate analysis. Results After a median follow-up of 41 months, 272 patients had local failure. Median GTV-CTV1 margin in Center1, 2 and 3 was 0.0, 3.7 and 9.7 mm, respectively. 51% of local recurrences were inside the GTV. No difference in distribution of LRs in relation to GTV surface (p = 0.4) or the dose to LRs (p = 0.2) was detected between the groups. A difference in LC was found univariate between the centers (p = 0.03), but not in multivariate analysis (p = 0.4). Conclusions No relation was found between the recurrences' distributions as function of the margins used at three centers. In multivariate analysis, local control was not influenced by the centers. [ABSTRACT FROM AUTHOR]

• Head and neck cancer patients at risk of distant metastases (DM) are difficult to identify. • We investigated the influence of initial tumor volume (cm3) on the risk of DM. • Gross tumor volumes (GTV) were extracted from treatment planning systems. • We found that GTV is an independent factor strongly associated with the risk of DM. • This may improve the selection of patients for intervention trials. Distant metastases (DM) in head and neck squamous cell carcinomas (HNSCC) are in most circumstances non-curable. The TNM staging system is insufficient to predict the risk of DM. This study investigates if the DM risk can be predicted using a multivariate model including pre-treatment total tumor volume for both p16-positive oropharyngeal squamous cell carcinoma (OPSCC) and all other sites (other HNSCC). The study includes patients with localized pharyngeal and laryngeal squamous cell carcinomas treated with primary radiotherapy from 2008-2017 from three head and neck cancer centers. Patients were identified in the Danish Head and Neck Cancer (DAHANCA) database. Total (nodal and primary) tumor volume (Gross Tumor Volume, GTV) was extracted from local treatment planning systems. The GTV was grouped by volume (cm3) in four intervals and included in a multivariate Cox proportional hazard regression controlled for pre-selected clinical values incl. stage. The study includes 2,865 patients, of which 321 (11 %) had DM post-treatment. The risk of DM was assessed in a multivariate model based on 2,751 patients (p16-positive OPSCC: 1,032; and other HNSCC: 1,719). There was a significant association between GTV and the risk of DM, and in tumor volumes ≥ 50 cm3 hazard ratios of 7.6 (2.5–23.4) for p16-positive OPSCC and 4.1 (2.3–7.2) in other HNSCC were observed. Tumor volume is an independent risk factor for DM. The addition of total tumor volume to a predictive model is important to identify subgroups of HNSCC patients at high risk of DM. [ABSTRACT FROM AUTHOR]

Purpose The DAHANCA 6 trial evaluated tumor response and morbidity after moderate accelerated radiotherapy compared to conventional fractionated radiotherapy in patients treated for glottic squamous cell carcinoma (SCC). Further, the failure pattern and incidence of new primary tumors were explored. Patients and methods Six hundred and ninety-four patients with non-metastatic glottic SCC were randomized between six or five weekly fractions (fx/w) of radiotherapy to the same total dose. The median treatment time was 38 and 46 days, respectively. The primary endpoint was loco-regional failure. Results Median follow-up time was 14.5 years. Of the 177 failures, 167 involved T-site. The cumulative incidence of loco-regional failure (LRF) was 21.6% in the 6 fx/w group and 29.3% in the 5 fx/w group and the corresponding hazard rate (HR) of LRF was 0.72 (CI: 0.53–0.97, p = 0.04). The effect of acceleration on LRF was especially evident in well differentiated tumors (HR = 0.42 (CI: 0.23–0.75) and in T1–2 tumors (HR = 0.60 (CI: 0.41–0.89)). The HR of laryngectomy was 0.72 (CI: 0.50–1.04) in the 6 fx/w group compared to the 5 fx/w group. The hazards of disease-specific death, event-free survival, and overall survival were comparable between the two groups. Significantly more patients experienced severe acute mucositis in the 6 fx/w group but the incidence of late morbidity was comparable between the groups. New primary tumors occurred in 22.5% of the patients. Conclusion Moderate accelerated radiotherapy significantly improved loco-regional control in patients with glottic SCC. [ABSTRACT FROM AUTHOR]

Abstract: Background: Comorbidity is common in head and neck squamous cell carcinoma (HNSCC) patients due to the etiology of the disease being primarily smoking. The aim of this study was to investigate the impact of comorbidity on survival in a national population-based cohort study on 9388 HNSCC-patients treated with radiotherapy (RT), to re-evaluate the prognostic impact of individual diseases within the Charlson Comorbidity Index (CCI), and to develop a revised head and neck comorbidity index (HN-CCI). Material and methods: A national cohort of 9388 HNSCC-patients treated with curative intended RT diagnosed from 1992 to 2008 was identified from the DAHANCA-database. Data on comorbidity prior to HNSCC-diagnosis was obtained from the National Patient Registry and adapted to the CCI. Results: By dividing the patients into two groups, we tested and validated which type of comorbidities within the CCI affected overall survival (OS) and cancer specific death (CSD). In total, 36% of patients had comorbidity. Six comorbid conditions within the CCI significantly reduced five-year OS probability: congestive heart failure, cerebrovascular disease, chronic pulmonary disease, peptic ulcer disease, liver disease, and diabetes, and based on these conditions the new head and neck specific comorbidity index was developed, the HN-CCI. Comorbidity according to HN-CCI had a highly significant impact on OS, whereas it was not associated with CSD. Chronological age was not associated with increased risk of CSD after controlling for comorbidity. Conclusions: Comorbidity is frequent in HNSCC patients and negatively impacts OS. Therefore assessment of comorbidity will be of great importance, both in order to treat/optimize patient’s health before radiotherapy, but also in order to be able to stratify/control for comorbidity in randomized trials to avoid bias. Re-evaluation of the CCI revealed that only six conditions had an impact on survival, and a new modified index to assess comorbidity for HNSCC-patients was developed. The performance of HN-CCI to stratify patients on survival was good and HN-CCI is highly recommended for future assessment of comorbidity and prognostic staging of radiotherapy-treated HNSCC-patients. [Copyright &y& Elsevier]

Abstract: Background and purpose: To develop a normal tissue complication probability (NTCP) model of radiation-induced biochemical hypothyroidism (HT) after primary radiotherapy for head and neck squamous cell carcinoma (HNSCC) with adjustment for latency and clinical risk factors. Patients and methods: Patients with HNSCC receiving definitive radiotherapy with 66–68Gy without surgery were followed up with serial post-treatment thyrotropin (TSH) assessment. HT was defined as TSH >4.0mU/l. Data were analyzed with both a logistic and a mixture model (correcting for latency) to determine risk factors for HT and develop an NTCP model based on mean thyroid dose (MTD) and thyroid volume. Results: 203 patients were included. Median follow-up: 25.1months. Five-year estimated risk of HT was 25.6%. In the mixture model, the only independent risk factors for HT were thyroid volume (cm3) (OR=0.75 [95% CI: 0.64–0.85], p <0.001) and MTD (Gy) (OR=1.12 [95% CI: 1.07–1.20], p <0.001). From the mixture NTCP-model individual dose constraints for a 25% risk of HT were 26, 38, 48 and 61Gy for thyroid volumes of 10, 15, 20 and 25cm3, respectively. Conclusions: Comparing the logistic and mixture models demonstrates the importance of latent-time correction in NTCP-modeling. Thyroid dose constraints in treatment planning should be individualized based on thyroid volume. [Copyright &y& Elsevier]

Abstract: Purpose: The critical weight loss observed in head and neck squamous cell carcinoma (HNSCC) patients following radiotherapy is mainly due to loss of lean body mass. This is associated with decreases in muscle strength, functional performance and Quality of Life (QoL). The present study investigated the effect of progressive resistance training (PRT) on lean body mass, muscle strength and functional performance in HNSCC patients following radiotherapy. Patients and methods: Following radiotherapy HNSCC patients were randomized into two groups: Early Exercise (EE, n =20) initiated 12weeks of PRT followed by 12weeks of self-chosen physical activity. Delayed Exercise (DE, n =21) initiated 12weeks of self-chosen physical activity followed by 12weeks of PRT. Lean body mass, muscle strength, functional performance and QoL were evaluated at baseline and after week 12 and 24. Results: In the first 12weeks lean body mass increased by 4.3% in EE after PRT and in the last 12weeks by 4.2% in DE after PRT. These increases were significantly larger than the changes after self-chosen physical activity (p ⩽0.005). Regardless of PRT start-up time, the odds ratio of increasing lean body mass by more than 4% after PRT was 6.26 (p <0.05). PRT significantly increased muscle strength, whereas functional performance increased significantly more than after self-chosen physical activity only after delayed onset of PRT. Overall QoL improved significantly more in EE than DE from baseline to week 12. Conclusion: PRT effectively increased lean body mass and muscle strength in HNSCC patients following radiotherapy, irrespectively of early or delayed start-up. [Copyright &y& Elsevier]

Abstract: Background and purpose: The aim of this report was to describe the incidence and prevalence of acute and late morbidity in the DAHANCA 6&7 multicentre randomised trial with accelerated radiotherapy for squamous cell carcinoma of the head and neck. Materials and methods: The DAHANCA 6&7 study included 1476 patients eligible for primary radiotherapy alone. Patients were randomised between five or six weekly fractions of conventional radiotherapy. The prescribed dose was 66–68Gy in 33–34 fractions. All patients were seen weekly during treatment and at regular intervals after completion where detailed morbidity recording was done. Reports from 1468 patients were available for analysis of treatment related morbidity. Results: Accelerated radiotherapy caused a significant (p <0.05) increase in the peak incidence of: use of analgesics (53% vs. 65%), dysphagia (35% vs. 45%), mucosal oedema (52% vs. 59%), and mucositis (33% vs. 53%). All acute reactions were reversible and healed within three months after radiotherapy. Loss of taste, xerostomia, and acute skin reaction was not different between the two groups. For all late endpoints except fibrosis and atrophy a decline in prevalence was observed in the years after radiotherapy, there was no significant difference between randomisation arms in any of the late endpoints. Conclusions: Six fractions per week, resulting in a one-week reduction in overall treatment time relative to conventional radiotherapy increased acute but not late morbidity. Since acceleration improves loco-regional tumour control, the schedule represents a significant improvement of the therapeutic ratio for head and neck radiotherapy and might be close to the maximal gain possible with accelerated fractionation alone. [Copyright &y& Elsevier]

Abstract: Background and purpose: Tumour HPV-positivity is a favourable prognostic factor in the radiotherapy of HNSCC, but the optimal radiotherapy regimen for HPV-positive HNSCC is not yet defined. Reducing overall treatment time is known to improve outcome in the radiotherapy of HNSCC as was also demonstrated in the randomised DAHANCA 6&7 trial. We aimed to assess the influence of tumour HPV-status, expressed by p16, on the response to accelerated fractionated radiotherapy in HNSCC through evaluation of the DAHANCA 6&7 trial. Materials and methods: Immunohistochemical detection of HPV-associated p16-expression was performed on FFPE-pre-treatment tumour-tissues from 794 patients enrolled in the DAHANCA 6&7 trial. The influence of tumour p16-status on loco-regional tumour control and survival as a function of fractionation schedule (5Fx/week vs 6Fx/week) was evaluated 5years after the completion of radiotherapy. Results: The significant and independent prognostic value of tumour p16-positivity in HNSCC radiotherapy was confirmed, with adjusted hazard ratios (HR) of 0.58 [0.43–0.78], 0.47 [0.33–0.67] and 0.54 [0.42–0.68] for loco-regional control, disease-specific and overall survival, respectively. Accelerated radiotherapy significantly improved loco-regional tumour control compared to conventional radiotherapy, adjusted HR: 0.73 [0.59–0.92] and the benefit of the 6Fx/week regimen was observed both in p16-positive (HR: 0.56 [0.33–0.96]) as well as in p16-negative tumours (HR: 0.77 [0.60–0.99]). Disease-specific survival was also significantly improved with accelerated radiotherapy in the group of p16-positive tumours (adjusted HR: 0.43 [0.22–0.82]). Conclusion: Accelerated radiotherapy significantly improves outcome in HNSCC compared to conventional fractionation. The observed benefit is independent of tumour p16-status and the use of a moderately accelerated radiotherapy regimen seems advantageous also for HPV/p16-positive HNSCC. [Copyright &y& Elsevier]

Abstract: Background and purpose: Patients with head and neck squamous cell carcinoma (HNSCC) and a low level of haemoglobin (Hb) often have a poor response to radiation which may be related to hypoxia induced radioresistance. The aim of the study was to evaluate the prognostic significance of low Hb level and its modification by transfusion in HNSCC patients treated with radiotherapy. The study was performed as a subrandomization in the DAHANCA 5 trial. Material and methods: Patients were randomized to treatment with the hypoxic radiosensitizer nimorazole or placebo, and in addition, patients with “low” pre-irradiation Hb values (females<13g/dL; males<14.5g/dL) were subrandomized to plus or minus transfusion. Transfusion was given with packed red blood cells with the aim to achieve a Hb level in the “high” value range. Results: A total of 414 patients were included, 243 patients had high Hb levels and 171 patients had low Hb levels. Of the low Hb patients, 82 were randomized to receive transfusion and 89 not to receive transfusion. The treatment arms were well balanced. In the majority of patients, transfusion resulted in increased Hb levels although this tended to decline throughout treatment. Patients with high Hb levels had a significantly better probability of locoregional control, disease-specific survival and overall survival compared to ‘low Hb no transfusion’ patients. In the low Hb group, transfusion did not improve the outcome in locoregional control, disease-specific survival or overall survival. In multivariate analyses, T and N classifications were significant for all outcome measures, whereas there was no significant influence of transfusion or Hb level on endpoints. Conclusion: The univariate prognostic significance of high Hb level was demonstrated in patients with HNSCC treated with radiotherapy; however, transfusion prior to and during treatment did not improve the outcome in patients with low Hb values. [Copyright &y& Elsevier]

Abstract: Background: Definition and treatment options for locally advanced non-resectable pancreatic cancer (LAPC) vary. Treatment options range from palliative chemotherapy to chemoradiotherapy (CRT). Several studies have shown that a number of patients become resectable after complementary treatment prior to surgery. Methods: From 2001 to 2005, 63 consecutive patients with unresectable LAPC received CRT. CRT was given at a dose of 50Gy/27 fractions, combined with UFT (300mg/m2/day) and folinic acid. Re-evaluation of resectability was planned 4–6weeks after completion of CRT. Results: Fifty-eight patients completed all 27 treatment fractions. Toxicity was generally mild, with 18 patients experiencing CTCAE grade 3 or worse acute reactions. One patient died following a treatment-related infection. Two patients developed grade 4 upper GI bleeding. Median survival was 10.6 (8–13) months. Eleven patients underwent resection, leading to a resection rate of 17%, and a median survival of 46 (23-nr) months. All 11 patients had a R0 resection. Median survival for the patients not resected was 8.8 (8–12) months. Conclusion: CRT with 50Gy combined with UFT, is a well-tolerated and effective treatment for patients with LAPC. R0 resection was possible in 17% leading to a long median survival of 46months in resected patients. [Copyright &y& Elsevier]