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Este artículo se encuentra disponible en la siguiente URL: https://www.sciencedirect.com/science/article/pii/S0167814022044991?via%3Dihub En este artículo de investigación también participan:Gianluca Ingrosso, Filippo Alongi, Shafak Aluwini, Stefano Arcangeli, Pierre Blanchard, Felipe Couñago, Gilles Créhange, Piet Dirix, Alfonso Gomez Iturriaga, Matthias Guckenberger, David Pasquier, Paul Sargos, Marta Scorsetti, Stéphane Supiot, Alison C. Tree, Almudena Zapatero, Jennifer Le Guevelou, Piet Ost y Claus Belka. Background and purpose: Oligometastatic prostate cancer is a new and emerging treatment field with only few prospective randomized studies published so far. Despite the lack of strong level I evidence, metastasis-directed therapies (MDT) are widely used in clinical practice, mainly based on retrospective and small phase 2 studies and with a large difference across centers. Pending results of ongoing prospective randomized trials, there is a clear need for more consistent treatment indications and radiotherapy practices. Material and methods: A European Society for Radiotherapy and Oncology (ESTRO) Guidelines Committee consisting of radiation oncologists’ experts in prostate cancer was asked to answer a dedicated questionnaire, including 41 questions on the main controversial issues with regard to oligometastatic prostate cancer. Results: The panel achieved consensus on patient selection and routine use of prostate-specific membrane antigen positron emission tomography (PSMA PET) imaging as preferred staging and restaging imaging. MDT strategies are recommended in the de novo oligometastatic, oligorecurrent and oligoprogressive disease setting for nodal, bone and visceral metastases. Radiation therapy doses, volumes and techniques were discussed and commented. Conclusion: These recommendations have the purpose of providing standardization and consensus to optimize the radiotherapy treatment of oligometastatic prostate cancer until mature results of randomized trials are available.

Luca Nicosia,1 Claudio Vitale,1 Francesco Cuccia,1 Vanessa Figlia,1 Niccolò Giaj-Levra,1 Rosario Mazzola,1 Francesco Ricchetti,1 Michele Rigo,1 Ruggero Ruggieri,1 Stefano Cavalleri,2 Filippo Alongi1,3 1Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Verona, Negrar, Italy; 2Urology Division, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Negrar, Italy; 3University of Brescia, Brescia, ItalyCorrespondence: Luca Nicosia, Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, via Don Sempreboni 5, 37034, Verona, Negrar, Italy, Tel +39 045-6014800, Fax +045-60148071, Email lucanicosia.rg@gmail.comAim: To evaluate the impact of Ialuril soft Gels® (HA) in reducing acute genito-urinary (GU) toxicity in patients treated with adjuvant or salvage radiotherapy for a prostate cancer relapse.Material and Methods: The data of 305 patients were retrospectively collected. One hundred and five patients underwent adjuvant radiotherapy (aRT), while 200 a salvage treatment (sRT). GU toxicity was evaluated according to CTCAE v5.0. Every patient received RT combined with HA.Results: Grade 1– 2 GU toxicity during RT was represented by: urgency (36%), dysuria (23%), increased urinary frequency (12.1%), and urinary retention (11.8%). Nevertheless, the majority of symptoms were present at the baseline. Grade 3 severe toxicity was represented by 10 (3.2%) cases of incontinence and 3 (1%) cases of urgency. The incidence of any-grade RT-related GU toxicity was significantly higher in the aRT group than the salvage group (esRT + sRT) (83.8% versus 64.5%). When comparing the incidence of any-grade RT-related GU toxicity in the aRT, esRT, and sRT groups we observed a significant correlation favoring sRT, over esRT, and aRT.Conclusion: Postoperative hypofractionated radiotherapy is safe and not correlated with increase of unexpected toxicity when administered with oral hyaluronic acid. A prospective study is necessary to confirm these results.Keywords: prostate cancer, hyaluronic acid, postoperative radiotherapy, salvage radiotherapy, hypofractionation, toxicity

To evaluate the impact of moderately hypofractionated postoperative radiotherapy (RT) in prostate cancer (PCa).The data of 304 surgically resected PCa patients were analyzed. One hundred and five patients underwent adjuvant RT (aRT), 77 early-savage RT (esRT), and 123 salvage RT (sRT). Biochemical relapse-free survival (BRFS), progression-free survival (PFS) and toxicity were analyzed. A propensity score matching (PSM) was performed to account for potential confounders between aRT and esRT groups.The median follow-up was 33 months. Three-year BRFS and PFS were 82 and 85.2%, respectively, in the overall population. At the multivariate analysis, Gleason score and hormone therapy were factors independently correlated with BRFS and PFS. After PSM, there was no difference in BRFS and PFS between aRT and esRT patients. Severe toxicity was represented by grade 3 urinary incontinence (3.5%) and urgency (1%), and aRT correlated with increased any-grade acute toxicity. Severe grade 3 gastrointestinal late toxicity occurred in 1.3% of cases.Postoperative moderately hypofractionated RT achieved acceptable disease control rate and demonstrated no increased or unexpected toxicity. Future prospective studies should evaluate the role of postoperative RT in patients with unfavorable disease characteristics.

Cardiac arrhythmias are a leading cause of mortality, morbidity, and sudden cardiac death (SCD). Current treatment strategies for ventricular tachycardia (VT) are effective for many patients; however, in several cases, this does not result in a cure. Despite significant clinical improvements, conventional catheter ablation remains relatively unsuccessful in achieving the best outcomes in some challenging cases. Stereotactic arrhythmia radioablation (STAR), which delivers precise high-dose radiation to well-defined targets with minimal damage to surrounding tissue, is emerging as a new potential treatment option, having the potential to be used for patients at high risk for catheter ablation or who have refractory VT. Ongoing studies and preliminary experiences on f the efficacy of STAR in patients with refractory VT have shown a reduction in VT recurrence and a promising early safety profile. However, STAR is in its infancy, and clinical evidence on its efficacy and safety is limited; thus, conclusions regarding the efficacy of STAR should be drawn with caution. Further investigation of long-term efficacy and tolerability is ongoing to substantiate this promising therapeutic option better. The present review describes the background and general principles, pretreatment procedures, clinical implications, and toxicity of STAR therapy.

PURPOSE Aim of this study is to assess the ability of contrast-enhanced CT image-based radiomic analysis to predict local response (LR) in a retrospective cohort of patients affected by pancreatic cancer and treated with stereotactic body radiation therapy (SBRT). Secondary aim is to evaluate progression free survival (PFS) and overall survival (OS) at long-term follow-up. METHODS Contrast-enhanced-CT images of 37 patients who underwent SBRT were analyzed. Two clinical variables (BED, CTV volume), 27 radiomic features were included. LR was used as the outcome variable to build the predictive model. The Kaplan-Meier method was used to evaluate PFS and OS. RESULTS Three variables were statistically correlated with the LR in the univariate analysis: Intensity Histogram (StdValue feature), Gray Level Cooccurrence Matrix (GLCM25_Correlation feature) and Neighbor Intensity Difference (NID25_Busyness feature). Multivariate model showed GLCM25_Correlation (P = 0.007) and NID25_Busyness (P = 0.03) as 2 independent predictive variables for LR. The odds ratio values of GLCM25_Correlation and NID25_Busyness were 0.07 (95%CI 0.01-0.49) and 8.10 (95%CI 1.20-54.40), respectively. The area under the curve for the multivariate logistic regressive model was 0.851 (95%CI 0.724-0.978). At a median follow-up of 30 months, median PFS was 7 months (95%CI 6-NA); median OS was 11 months (95%CI 10-22 months). CONCLUSIONS This analysis identified a radiomic signature that correlates with LR. To confirm these results, prospective studies could identify patient sub-groups with different rates of radiation dose-response to define a more personalized SBRT approach.

Introduction: The aim of our study was to evaluate the efficacy and toxicity of a daily-adaptive MR-guided SBRT on 1.5 T MR-linac in patients affected by lymphnode oligometastases from PCa. Materials and Methods: The present study is a prospective observational study conducted in a single institution (protocol n°: MRI / LINAC n. 23748). Patients with oligometastatic lymphnodes from PCa treated with daily-adaptive MR-guided SBRT on 1.5T MR-linac were included in the study. Minimum required follow-up of 3 months after SBRT. Primary end-point was local progression-free survival (LPFS). Secondary end-points were: nodal progression-free survival (NPFS), and progression-free survival (PFS), and toxicity. Results: 118 lymphnode oligometastases from PCa were treated with daily-adaptive 1.5T MR-guided SBRT in 63 oligometastatic patients. 63.5% patients were oligoprogressive and 36.5% oligoprogressive. Two-year LPFS was 94.5%. Median NPFS was 22.3 months, and the 2-year NPFS was 46.5%. Having received hormone therapy before SBRT was correlated with lower NPFS at the multivariate analysis (1-y NPFS 87.1% versus 42.8%; p= 0.002 - HR 0.199, 95% CI 0.073-0.549). Furthermore, the oligorecurrent state during ADT was correlated with a lower NPFS than the oligoprogressive state. Median PFS was 10.3 months, the 2-year PFS was 32.4%. Patients treated with hormone therapy before SBRT had a significantly lower 1-year PFS the others (28% versus 70.4%; p= 0.01 - HR 0.259, 95% CI 0.117-0.574). No acute and late toxicities occurred during treatment. Conclusion: the present is the largest prospective study of 1.5T lymphnode SBRT on MR-linac in patients with PCa. Lymphnode SBRT by 1.5T MR-linac provides high local control rates with an excellent toxicity profile.

Background and purpose: Stereotactic body radiotherapy (SBRT) has a consolidated role in the treatment of bone oligometastases from prostate cancer (PCa). While the evidence for spinal oligometastases SBRT was robust, its role in non-spinal-bone metastases (NSBM) is not standardized. In fact, there was no clear consensus about dose and target definition in this setting. The aim of our study was to evaluate efficacy, toxicity, and the pattern of relapse in SBRT delivered to NSBM from PCa. Materials and methods: From 2016 to 2021, we treated a series of oligo-NSBM from PCa with 68Ga-PSMA PET/CT-guided SBRT. The primary endpoint was local progression-free survival (LPFS). The secondary endpoints were toxicity, the pattern of intraosseous relapse, distant progression-free survival (DPFS), polimetastases-free survival (PMFS), and overall survival (OS). Results: a total of 150 NSBM in 95 patients were treated with 30–35 Gy in five fractions. With a median follow-up of 26 months, 1- and 3 years LPFS was 96.3% and 89%, respectively. A biologically effective dose (BED) ≥ 198 Gy was correlated with improved LPFS (p = 0.007). Intraosseous relapse occurred in eight (5.3%) cases. Oligorecurrent disease was associated with a better PMFS compared to de novo oligometastatic disease (p = 0.001) and oligoprogressive patients (p = 0.007). No grade ≥ 3 toxicity occurred. Conclusion: SBRT is a safe and effective tool for NSBM from PCa in the oligometastatic setting. Intraosseous relapse was a relatively rare event. Predictive factors of the improved outcomes were defined.

Background Brainstem metastases (BSM) are associated with a poor prognosis and their management represents a therapeutic challenge. BSM are often inoperable and, in absence of randomized trials, the optimal radiation treatment of BSM remains to be defined. We evaluated the efficacy and toxicity of linear accelerator (linac)-based stereotactic radiosurgery (SRS) and hypofractionated steretotactic radiotherapy (HSRT) in the treatment of BSM in a series of patients treated in different clinical centers. Methods We conducted a multicentric retrospective study of patients affected by 1–2 BSM from different histologies who underwent SRS/HSRT. Freedom from local progression (FLP), cancer-specific survival (CSS), overall survival (OS), and treatment-related toxicity were evaluated. In addition, predictors of treatment response and survivals were evaluated. Results Between 2008 and 2021, 105 consecutive patients with 111 BMS who received SRS or HSRT for 1–2 BSM were evaluated. Median follow-up time was 10 months (range 3–130). One-year FLP rate was 90.4%. At the univariate analysis, tumor volume ≤ 0.4 cc, and concurrent targeted therapy were associated with longer FLP, with combined treatment that remained a significant independent predictor [0.058, HR 0.139 (95% CI 0.0182–1.064]. Median OS and CSS were 11 months and 14.6 months, respectively. At multivariate analysis, concurrent targeted therapy administration was significantly associated with longer OS [HR 0.514 (95%CI 0.302–0.875); p = 0.01]. Neurological death occurred in 30.4% of patients, although this was due to local progression in only 3 (2.8%) patients. Conclusion Linac-based SRS/HSRT offers excellent local control to patients with BSM, with low treatment-related toxicity and no apparent detrimental effects on OS. When treated with ablative intent, BSM are an uncommon cause of neurological death. The present results indicates that patients with BSM should not be excluded a priori from clinical trials.

Background and purpose: Although chemotherapy, biological agents, and radiotherapy (RT) are cornerstones of the treatment of multiple myeloma (MM), the literature regarding the possible interactions of concurrent systemic treatment (CST) and RT is limited, and the optimal RT dose is still unclear. Materials and methods: We retrospectively analyzed the records of patients who underwent RT for MM at our institution from 1 January 2005 to 30 June 2020. The data of 312 patients and 577 lesions (treated in 411 accesses) were retrieved. Results: Most of the treated lesions involved the vertebrae (60%) or extremities (18.9%). Radiotherapy was completed in 96.6% of the accesses and, although biologically effective doses assuming an α/β ratio of 10 (BED 10) > 38 Gy and CST were significantly associated with higher rates of toxicity, the safety profile was excellent, with side effects grade ≥2 reported only for 4.1% of the accesses; CST and BED 10 had no impact on the toxicity at one and three months. Radiotherapy resulted in significant improvements in performance status and in a pain control rate of 87.4% at the end of treatment, which further increased to 96.9% at three months and remained at 94% at six months. The radiological response rate at six months (data available for 181 lesions) was 79%, with only 4.4% of lesions in progression. Progression was significantly more frequent in the lesions treated without CST or BED 10 < 15 Gy, while concurrent biological therapy resulted in significantly lower rates of progression. Conclusion: Radiotherapy resulted in optimal pain control rates and fair toxicity, regardless of BED 10 and CST; the treatments with higher BED 10 and CST (remarkably biological agents) improved the already excellent radiological disease control.

Background: Management of Ras wild-type colorectal cancer (CRC) patients upon disease progression after the successful use of targeted treatment with anti-EGFR monoclonal antibodies and backbone chemotherapy remains a clinical challenge. Summary: Development of treatment resistance with prevalence of preexisting RAS mutated clones, RAS mutation conversion, truncation of extracellular receptor domains as well as HER2 and MET amplification are molecular events that can be difficult to follow without the use of sophisticated laboratory techniques. The clinical hurdle of re-biopsy and tumor heterogeneity can be overcome by the implementation of next-generation sequencing (NGS) to analyze circulating tumor DNA (ctDNA) and identify druggable mutations or recovery of RAS-wildness. In this opinion paper, we summarize with critical thinking the clinical approach to be followed after the failure of first-line treatment in Ras wild-type CRC tumors with the use of NGS. Rechallenge with anti-EGFR inhibitors, in case of persistent or recovery of RAS-wildness, and targeted approach of specific mutations (BRAF inhibitors), amplifications (anti-Her2 treatment), or fusion proteins (NTRK inhibitors) can by guided by the use of NGS. The use of NGS platforms for serial analysis of ctDNA is an important step to better understand the molecular landscape of metastatic CRC and guide clinical decisions. Key Messages: NGS should be considered a mainstay in clinical practice for the management of CRC patients and health authorities should consider reimbursing its use in the appropriate clinical settings.

Cutaneous sarcomas are a heterogeneous group of rare mesenchymal neoplasms representing less than 1% of malignant tumors. Histology report remains the cornerstone for the diagnosis of these tumors. The most important clinicopathologic parameters related to prognosis include larger tumor size, high mitotic index, head and neck location, p53 mutations, depth of infiltration and histological grade, vascular and perineural invasion as well as the surgical margins status. Applying advanced biopsy techniques might offer more precise assessment of surgical margins, which constitutes a significant precondition for the management of these tumors. The management of cutaneous soft tissue sarcomas requires a multidisciplinary approach. Surgery remains the standard treatment, nonetheless adjuvant therapy may be required, consisting of radiotherapy, chemotherapy, and molecular targeted therapies to improve treatment outcomes. The role of molecular profiling in the treatment of uncontrolled disease is promising, but it may be offered to a relatively small proportion of patients and its use is still considered experimental in this setting. Due to the rarity of the disease, there is a need for knowledge and experience to be shared, pooled, organized and rationalized so that recent developments in medical science can have a major impact on the disease course. Multicenter clinical trials are needed to improve the care of patients with cutaneous sarcomas. info:eu-repo/semantics/publishedVersion

We aimed to overcome intratumoral heterogeneity in clear cell renal cell carcinoma (clearRCC). One hundred cases of clearRCC were sampled. First, usual standard sampling was applied (1 block/cm of tumor); second, the whole tumor was sampled, and 0.6 mm cores were taken from each block to construct a tissue microarray; third, the residual tissue, mapped by taking pieces 0.5 × 0.5 cm, reconstructed the entire tumor mass. Precisely, six randomly derived pieces of tissues were placed in each cassette, with the number of cassettes being based on the diameter of the tumor (called multisite 3D fusion). Angiogenic and immune markers were tested. Routine 5231 tissue blocks were obtained. Multisite 3D fusion sections showed pattern A, homogeneous high vascular density (10%), pattern B, homogeneous low vascular density (8%) and pattern C, heterogeneous angiogenic signatures (82%). PD-L1 expression was seen as diffuse (7%), low (33%) and absent (60%). Tumor-infiltrating CD8 scored high in 25% (pattern hot), low in 65% (pattern weak) and zero in 10% of cases (pattern desert). Grading was upgraded in 26% of cases (G3–G4), necrosis and sarcomatoid/rhabdoid characters were observed in, respectively, 11 and 7% of cases after 3D fusion (p = 0.03). CD8 and PD-L1 immune expressions were higher in the undifferentiated G4/rhabdoid/sarcomatoid clearRCC subtypes (p = 0.03). Again, 22% of cases were set to intermediate to high risk of clinical recurrence due to new morphological findings of all aggressive G4, sarcomatoid/rhabdoid features by using 3D fusion compared to standard methods (p = 0.04). In conclusion, we propose an easy-to-apply multisite 3D fusion sampling that negates bias due to tumor heterogeneity.

Introduction: The aim of our study was to evaluate the efficacy and toxicity of a daily adaptive MR-guided SBRT on 1.5 T MR-linac in patients affected by lymph node oligometastases from PCa. Materials and Methods: The present study is a prospective observational study conducted in a single institution (protocol n°: MRI/LINAC n. 23748). Patients with oligometastatic lymph nodes from PCa treated with daily adaptive MR-guided SBRT on 1.5 T MR-linac were included in the study. There was a minimum required follow-up of 3 months after SBRT. The primary end-point was local progression-free survival (LPFS). The secondary end-points were: nodal progression-free survival (NPFS), progression-free survival (PFS), and toxicity. Results: A total of 118 lymph node oligometastases from PCa were treated with daily adaptive 1.5 T MR-guided SBRT in 63 oligometastatic patients. Of the patients, 63.5% were oligorecurrent and 36.5% were oligoprogressive. The two-year LPFS was 90.7%. The median NPFS was 22.3 months and the 2-year NPFS was 46.5%. Receiving hormone therapy before SBRT was correlated with a lower NPFS at the multivariate analysis (1 y NPFS 87.1% versus 42.8%; p = 0.002–HR 0.199, 95% CI 0.073–0.549). Furthermore, the oligorecurrent state during ADT was correlated with a lower NPFS than was the oligoprogressive state. The median PFS was 10.3 months and the 2-year PFS was 32.4%. Patients treated with hormone therapy before SBRT had a significantly lower 1-year PFS the others (28% versus 70.4%; p = 0.01–HR 0.259, 95% CI 0.117–0.574). No acute and late toxicities occurred during treatment. Conclusions: The present study is the largest prospective study of 1.5 T lymph node SBRT on MR-linac in patients with PCa. Lymph node SBRT by 1.5 T MR-linac provides high local control rates with an excellent toxicity profile.

Purpose: The present study reports the preliminary outcomes in terms of adverse events and quality of life in the first 100 patients treated with 1.5T MR-guided daily-adaptive stereotactic body radiotherapy for prostate cancer. Methods: From October 2019 to December 2020, 100 patients, enrolled in a prospective study, received MR-guided SBRT for prostate cancer. Rectal spacer insertion was optional and administered in 37 patients. In total, 32 patients received androgen deprivation therapy in accordance with international guidelines. A prospective collection of data regarding toxicity and quality of life was performed. Results: The median age was 71 years (range, 52–84). The median total dose delivered was 35 Gy (35–36.25 Gy) in five sessions, either on alternate days (n = 25) or consecutive days (n = 75). For acute toxicity, we recorded: seven cases of acute G2 urinary pain and four cases of G2 gastrointestinal events. The median follow-up was 12 months (3–20), recording three late G2 urinary events and one G3 case, consisting of a patient who required a TURP 8 months after the treatment. For gastrointestinal toxicity, we observed 3 G ≥ 2 GI events, including one patient who received argon laser therapy for radiation-induced proctitis. Up to the last follow-up, all patients are alive and with no evidence of biochemical relapse, except for an M1 low-volume patient in distant progression two months after radiotherapy. QoL evaluation reported a substantial resolution of any discomfort within the second follow-up after radiotherapy, with the only exception being sexual items. Notably, after one year, global health items were improved compared to the baseline assessment. Conclusions: This study reports very promising outcomes in terms of adverse events and QoL, supporting the role of 1.5T MR-guided SBRT for prostate cancer. To date, this series is one of the first and largest available in the literature. Long-term results are warranted.

Purpose To explore the benefit yielded by radiotherapy (RT), we report a series of metastatic renal cell carcinoma (RCC) patients treated with concomitant RT plus Nivolumab. Methods/patients Patients undergoing Nivolumab treatment plus concomitant RT (ablative or palliative) were included. RT was defined Ablative if >5 Gy/fraction were delivered. Results Ablative RT intent was the only independent predictor of both progression free and overall survival (HR 3.51, 95% CI 1.6–7.5, p = 0.0012 and HR 2.8, 95% CI 0.99–8.07, p = 0.05, respectively). Conclusion Ablative RT may improve oncologic outcomes in selected patients with metastatic RCC treated with Nivolumab as compared to palliative RT.

Androgen-deprivation therapy (ADT), with or without palliative local treatments, is the standard of care for many patients with locally-advanced and/or metastatic prostate cancer. However, the possible cardiovascular (CV) risks associated with gonadotropin-releasing hormone (GnRH) antagonists and agonists continue to be the subject of concern, especially in a patient population that may already be at increased CV risk. The present review provides a narrative summary of the evidence regarding the CV risks associated with GnRH antagonists and agonists from randomized clinical trials (RCTs), real-world evidence, and meta-analyses. From RCTs, it appears clear that there is a direct class effect for CV risk in patients with prostate cancer being administered GnRH agonists and antagonists, with the latter being associated with reduced CV risk. Real-world data and the available meta-analyses largely indicate that CV risk is lower with GnRH antagonists than with GnRH agonists. A review of the pathophysiological mechanisms of gives further support to the possibility that GnRH antagonists are associated with lower CV risk than agonists. It can be highlighted that when treating patients with advanced or metastatic prostate cancer it is important to screen for underlying comorbidities prior to choosing the most appropriate therapy; moreover, patients should be closely monitored for factors associated with CV risk in order to optimize outcomes. Further studies are needed to define the most appropriate treatment according to the individual patient characteristics.

Spasticity is a clinical condition secondary to central nervous system damage, which impairs patients' mobility and quality of life. Stereotactic radiosurgery (SRS) to the spinal roots responsible of the spasms might represent a non-invasive therapy. The present are the preliminary results of the first clinical use of this novel technique.

Breast cancer is a heterogenous disease with a deep tailoring level. Evidence is accumulating on the role of stereotactic body radiotherapy (SBRT) in the management of oligometastatic disease, however this is limited in breast cancer. The aim of the present study is to show the effectiveness of SBRT in delaying the switch to a subsequent systemic treatment in oligoprogressive breast cancer patients. Retrospective analysis from two Institutions. Primary endpoint: time to next systemic treatment (NEST). Secondary endpoints: freedom from local progression (FLP), time to the polymetastatic conversion (tPMC) and overall survival (OS). One-hundred fifty-three (153) metastases in 79 oligoprogressive breast cancer patients were treated with SBRT. Median follow-up 24 months. Median NEST 8 months. Predictive factor of NEST at the multivariate analysis (MVA) was the number of treated oligometastases (HR 1.765, 95%CI 1.322-2.355; p =0.01). Systemic treatment after SBRT was changed in 29 patients for polymetastatic progression and in 10 patients for oligometastatic progression6 months after SBRT. The 2-year FLP in the overall population was 86.7%. A biological effective dose (BED)70Gy

PURPOSE/OBJECTIVE(S): stereotactic ablative radiotherapy (SABR) has been shown to increase survival rates in oligometastatic disease (OMD), but local control of colorectal metastases still remains poor. We aimed to identify potential predictive factors of SBRT response through a multicenter large retrospective database and to investigate how lung SBRT can impact on the progression to the polymetastatic disease (PMD). MATERIALS/METHODS: the study involved 22 centers, and was approved by the Ethical Committee (Prot. Negrar 2019-ZT). 1023 lung metastases treated with SBRT in 622 patients were reported. The median BED was 105 Gy10. Lesion diameter GTV, PTV volume, dose, fractionations, and site of primary tumor were evaluated as potential predictive marker for SBRT response for the primary end-point local progression-free survival (LPFS). EGFR, KRAS, NRAS, BRAF, and MSI were also evaluated. Secondary end-point was the time to the polymetastatic conversion (ttPMC). RESULTS: the median follow-up was 26 months (range 3-117 months). The median lesion diameter was 13 mm (range 4-58 mm). The 2- and 3-year LPFS were 75.6% and 71%, respectively. At the univariate analysis, BED ≥125Gy10 was associated with improved LPFS (2-year: 94.1% versus 72.6%; P = < 0.0001), single fraction SBRT correlated with better LPFS in the overall population (2-year: 80.6% versus 73.7%; P = 0.03), but no significant difference was observed when considering the population treated with BED > 100 Gy10. Lesion diameter ≤19 mm correlated with improved LPFS (2-year 80% versus 60%; P = < 0.0001). The median ttPMC was 26 months, and the 2-year ttPMC was 54.5%. The median PFS was 11.3 months. After SABR, 36% patients had polymetastatic relapse, 39.5% patients had an oligometastatic relapse, and 24.5% patients had no further relapse. CONCLUSION: the present is the largest series of lung colorectal metastases treated with SABR. The results support the use of SBRT in lung oligometastatic colorectal cancer patients as it might delay the transition to PMD or offer relatively long disease-free period in selected cases. Several biological and clinical predictive factors were identified to assure the highest local control, on the basis of which a decisional algorithm will be derived.

Purpose/Objective(s) Pancreatic ductal adenocarcinoma (PDAC) is highly refractory to systemic treatment, including radiotherapy (RT) either as alone or in combination with chemotherapy. Magnetic resonance (MR)-guided RT is a novel treatment technique which conjugates the high MR imaging contrast resolution to the possibility of re-adapting treatment plan to daily anatomical variations. Magnetic field (MF) might exert a biological effect that could be exploited to enhance radiation effect. The aim of the present study was to lay the preclinical basis of the MF effect by exploring how it modifies the response to radiation in organoid cultures established from PDAC. Materials/Methods The short-term effect of radiation, alone or in combination with MF, was evaluated in patient-derived organoids (PDOs) and monolayer cell cultures. Cell viability, apoptotic cell death, and organoid size following exposure to the treatment were evaluated. Results PDOs demonstrated limited sensitivity at clinically relevant doses of radiation. The combination of radiation and MF demonstrated superior efficacy than monotherapy in almost all the PDOs tested. PDOs treated with combination of radiation and MF were significantly smaller in size and some showed increased cell death as compared to the monotherapy with radiation. Conclusion Long-time exposure to 1.5T MF can increase the therapeutic efficacy of radiation in PDAC organoids.

PURPOSE/OBJECTIVE(S) MR-guided radiotherapy is a potential game changer in the field of radiation oncology, given the optimal visualization of the pelvic anatomy and the possibility to daily recalculate the plan based on real-time anatomy conditions. We report preliminary dosimetric data concerning the use of 1.5-T MR-guided daily-adaptive radiotherapy for abdomino-pelvic lymph-nodal oligometastases. We aimed to assess the impact of this technology on mitigating daily variations for both target coverage and organs-at-risk (OARs) sparing. MATERIALS/METHODS A total of 150 sessions for 30 oligometastases in 23 patients were analyzed. All patients were treated with MR-guided stereotactic body radiotherapy (SBRT) for a total dose of 35 Gy in 5 fractions. For each fraction, a quantitative analysis was performed for PTV volume, V35 Gy and Dmean. Similarly, for OARs we assessed daily variations of volume, Dmean, Dmax. Any potential statistically significant change between baseline planning and daily-adaptive sessions was assessed using the Mann-Whitney test, assuming a P-value < 0.05 as significant. RESULTS Median baseline PTV, bowel, bladder and single intestinal loop (in the case of targets very close to intestine) volumes were respectively 6.2cc (range, 0.7-41.2cc), 993cc (119-3654cc), 75cc (39.7-202.9cc), 15.7cc (9.1-37.7cc). No significant volume variations were detected for PTV (P = 0.17) bowel (P = 0.12), bladder (P = 0.14) and single intestinal loops (P = 0.21). Median baseline V35 Gy and Dmean for PTV were respectively 83.75% (72-98.8%) and 35.6 Gy (34.6-36.1 Gy). We recorded a positive trend in favor of daily-adaptive strategy vs baseline planning for improved target coverage (P = 0.06 and P = 0.07 for PTV-V35 Gy and PTV-Dmean). Concerning OARs, a significant difference was observed in favor of daily-adapted treatments in terms of single intestinal loop Dmax [26.9 Gy (13.2-26.9 Gy) at baseline vs 24 Gy (12.1-24 Gy); P = 0.014] and Dmean [16 Gy (6.518 Gy) at baseline vs 13.7 Gy (6.7-17.6 Gy); P = 0.0016]. For both bladder and bowel no significant differences were observed for Dmax and Dmean: for bladder, median Dmax was 15.3 Gy (0.4-34.3 Gy) at baseline vs 14.6 Gy (0.7-34.3 Gy), P = 0.24; median Dmean was 2.2 Gy (0.2-16.6 Gy) at baseline vs 2.2 Gy (0.2-16.4 Gy), P = 0.30. Similarly for bowel, no differences in terms of Dmax [28.7 Gy (7.7-34 Gy) vs 27.9 Gy (7.8-33.1 Gy); P = 0.06] and Dmean [4.3 Gy (1.3-10.9 Gy) vs 3.9 Gy (1.4-10.5 Gy); P = 0.25] were observed. CONCLUSION Daily-adaptive MR-guided SBRT reported a significantly improved single intestinal loop sparing for lymph-nodal oligometastases. A minor advantage was also reported in terms of PTV coverage, although not statistically significant. The potentially improved safety profile of MR-guided SBRT may lead the way to propose ultra-hypofractionated schedules or single fraction treatments. AUTHOR DISCLOSURE F. Cuccia: None. M. Rigo: None. D. Gurrera: None. L. Nicosia: None. V. Figlia: None. N. Giaj-Levra: None. R. Mazzola: None. F. Ricchetti: None. G. Attina: None. A. De Simone: None. S. Naccarato: None. G. Sicignano: None. R. Ruggieri: Honoraria; Elekta, Stockholm, Sweden. Consultant; Elekta, Stockholm, Sweden. F. Alongi: Honoraria; Elekta, Stockholm, Sweden. Consultant; Elekta, Stockholm, Sweden.