Background:Genitourinary (GU) or gastrointestinal (GI) complications and tumor relapse can occur in the long term after radiotherapy for prostate cancer. Objective:To assess the late tolerance and relapse-free survival (RFS) in patients undergoing hypofractionated stereotactic boost therapy after external beam radiotherapy (EBRT) for intermediate-risk prostate cancer. Design setting and participants:Seventy-six patients with intermediate-risk prostate carcinoma between August 2010 and April 2013 were included. The first course delivered a dose of 46 Gy by conventional fractionation; the second course was a boost of 18 Gy (3 × 6 Gy) within 10 d. Outcome measurements and statistical analysis:GU and GI toxicities were evaluated as the primary outcomes. The secondary outcomes were overall survival and RFS. The cumulative incidence of toxicity was calculated using a competing-risk approach. Overall survival and RFS were estimated using the Kaplan-Meier method. Results and limitations:The median follow-up period was 88 mo (range, 81-99 mo). Sixty (79%) patients were treated with the CyberKnife and 16 (21%) using a linear accelerator. The cumulative incidences of GU and GI grade ≥2 toxicities at 120 mo were 1.4% (95% confidence interval [CI]: 0.1-6.6%) and 11.0% (95% CI: 5.1-19.4%), respectively. The overall survival and RFS rates at 8 yr were 89.1% (95% CI: 77-95%) and 76.9% (95% CI: 63.1-86.1), respectively. Conclusions:A very long follow-up showed low GU and GI toxicities after a hypofractionated stereotactic boost after EBRT for intermediate-risk prostate cancer. Dose escalation of the boost delivered by hypofractionated radiation therapy appears safe for use in future trials. Patient summary:We found low toxicity and good survival rates after a short and high-precision boost after external beam radiotherapy for intermediate-risk prostate cancer, with a long-term follow-up of 88 mo. This long-term treatment is safe and should be considered in future trials.

IntroductionSince radical treatments in low risk prostate cancer do not improve overall survival in comparison to active surveillance, preserving quality of life (QOL) remains the key objective. Active surveillance of indolent prostate cancer avoids curative treatment side-effects but necessitates repeated biopsies. Focal stereotactic body radiation therapy (focal SBRT) may be an alternative. This non-randomized Phase-II trial examined the feasibility and safety of focal SBRT for low and favorable intermediate-risk prostate cancer.MethodsPatients were recruited in 2016–2019 if they had: localized CAPRA ≤ 3 prostate adenocarcinoma; an isolated PIRADS≥4 macroscopic tumor on MRI; WHO Performance Status 0-1; and no major urinary symptoms. 36.25 Gy (80% isodose prescription) were delivered in 5 fractions every other day. Primary outcome was delay between focal SBRT and salvage-treatment initiation. Secondary outcomes were: acute/late genitourinary/rectal toxicity; biological, clinical and MRI local control; and change in QOL measures.ResultsOver a median follow-up of 36 months, salvage prostatectomy in the 24 eligible patients was never required. Three-year biochemical progression-free survival was 96%. The single biochemical recurrence was a small (2-mm) Gleason 6 (3 + 3) lesion in the non-irradiated lobe. All 19 patients with ≥1 post-treatment MRI evaluations demonstrated complete radiological response. Acute/late grade ≥3 toxicities did not occur: all acute toxicities were grade-1 genitourinary (38% patients), grade-2 genitourinary (8%), or grade-1 rectal (13%) toxicities. There was one (4%) late grade-1 genitourinary toxicity. QOL was unchanged at last follow-up, as shown by IPSS (2.86 to 3.29, p>0.05), U-QOL (0.71 to 0.67, p>0.05), and IIEF5 (the 14 initially potent patients maintained potency (IIEF5 > 16)).ConclusionFocal SBRT is feasible, well-tolerated, and preserves QOL. This innovative robotized approach challenges active surveillance.

Introduction/Background In Luxembourg, brachytherapy (BT) is not widely available. The focus of this research was to assess the feasibility, safety, and efficacy of Stereotactic Body Radiation Therapy (SBRT) as a boost in locally advanced cervical cancer. Methodology Between 2017–2019, patients with histologically proven FIGO (2018) stages IB-IVA treated by external radiotherapy (VMAT): 50 Gy in 28 fractions to the pelvic +/- lomboaortic lymph nodes and 60.04 Gy using a simultaneous integrated boost to the macroscopic tumor +/- positive FDG-PET-CT scan nodes were included. Concurrent weekly cisplatin (40 mg/m2) was given. Following concurrent radio-chemotherapy (CCRT), a pelvic computed tomography scan with a magnetic resonance imaging simulation were performed within the 1st week after CCRT. Target volumes (GTV-T, HR-CTV, PTV) and organs at risk (bladder, rectum, sigmoid, and bowel bag) were define on the MRI. The boost prescription was 13Gy in two fractions delivered in two consecutive days. SBRT boost was delivered using a Cyberknife®M6 and tracking based fiducial markers. A 12-week MRI and Pet-Ct were used to determine the therapeutic outcomes. Results Eleven patients were included, median age was 59 years (57–68), 100% had a squamous cell carcinoma, 45% had a stage ≥ IIIC. The median overall treatment time was 52 days (Q1–3: 49.5–56). With a median follow up of 20 months (12.5–31), the local control was 73%. Three patients relapsed: external parametrial areas (n=2), pre-sacral node (n=1). No acute genito-urinary toxicity (Grade > II) was observed, 18% had acute grade III gastrointestinal toxicity. The most common long-term toxicity were grade I-II genito-urinary and gastro intestinal, no Grade ≥ III was observed. Progression free survival during the median follow-up of 20 months was 71.7%. Conclusion SBRT boost seems feasible and well tolerable, although it cannot substitute BT. Further studies with longer follow-up periods are warranted to confirm long-term outcomes.

Purpose: The aim of this analysis was to assess the 5-year tolerance and survival in patients undergoing hypofractionated stereotactic boost after external beam radiation therapy (EBRT) for intermediate-risk prostate cancer. Methods and Materials: Between August 2010 and April 2013, 76 patients with intermediate-risk prostate carcinoma were included in the study. A first course delivered 46 Gy using conventional fractionation. The second course delivered a boost of 18 Gy (3 x 6 Gy) within 10 days using stereotactic body radiation therapy (SBRT). Gastrointestinal and genitourinary toxicities were assessed according to the National Cancer Institute's Common Terminology Criteria for Adverse Events v4.0. Secondary outcome measures were overall, biochemical relapseefree, and relapse-free survival; prostate-specific antigen kinetics; and patient functional status (urinary and sexual) according to the International Index of Erectile Function and International Prostate Symptom Score questionnaires. Results: Sixty patients (79%) were treated by CyberKnife and 16 (21%) by linear accelerator. Median follow-up was 62 months (range, 29-69). The cumulative incidence of genitourinary and gastrointestinal grade >= 2 toxicities at month 60 after the end of radiation therapy was 1.4% (95% confidence interval [CI], 0.1%-6.6%) and 9.3% (95% CI, 4.1%-17.1%), respectively. Biochemical relapse-free and relapse-free survival rates at 5 years were 87.4% (95% CI, 77.1%-93.2%) and 86.2% (95% CI, 75.8-92.3), respectively. The mean (standard deviation) prostate-specific antigen variation within 3 months and 5 years post-radiation therapy was -1.20 ng/mL/mo (0.79) and -1.30 ng/mL/y (1.05), respectively. There was no significant difference between the International Prostate Symptom quality of life score between inclusion and month 60. For the International Index of Erectile Function, there was a significant difference between inclusion and month 60 (P = .005), with a higher proportion of severe/noninterpretable disorders at 60 months. Conclusions: The results of the trial demonstrate that the EBRT and SBRT combination is well tolerated and yields good efficacy results. These data provide a good basis for comparing EBRT and brachytherapy boost to EBRT and SBRT boost in future prospective studies. (C) 2019 Elsevier Inc. All rights reserved.

The purpose of this study was to determine the dynamic contributions of different immune cell subsets to primary and abscopal tumor regression after hypofractionated radiation therapy (hRT) and the impact of anti-PD-1 therapy. A bilateral syngeneic FSA1 fibrosarcoma model was used in immunocompetent C3H mice, with delayed inoculation to mimic primary and microscopic disease. The effect of tumor burden on intratumoral and splenic immune cell content was delineated as a prelude to hRT on macroscopic T1 tumors with 3 fractions of 8 Gy while microscopic T2 tumors were left untreated. This was performed with and without systemic anti-PD-1. Immune profiles within T1 and T2 tumors and in spleen changed drastically with tumor burden in untreated mice with infiltrating CD4+ content declining, while the proportion of CD4+ Tregs rose. Myeloid cell representation escalated in larger tumors, resulting in major decreases in the lymphoid:myeloid ratios. In general, activation of Tregs and myeloid-derived suppressor cells allow immunogenic tumors to grow, although their relative contributions change with time. The evidence suggests that primary T1 tumors self-regulate their immune content depending on their size and this can influence the lymphoid compartment of T2 tumors, especially with respect to Tregs. Tumor burden is a major confounding factor in immune analysis that has to be taken into consideration in experimental models and in the clinic. hRT caused complete local regression of primary tumors, which was accompanied by heavy infiltration of CD8+ T cells activated to express IFN-γ and PD-1; while certain myeloid populations diminished. In spite of this active infiltrate, primary hRT failed to generate the systemic conditions required to cause abscopal regression of unirradiated microscopic tumors unless PD-1 blockade, which on its own was ineffective, was added to the RT regimen. The combination further increased local and systemically activated CD8+ T cells, but few other changes. This study emphasizes the subtle interplay between the immune system and tumors as they grow and how difficult it is for local RT, which can generate a local immune response that may help with primary tumor regression, to overcome the systemic barriers that are generated so as to effect immune regression of even small abscopal lesions.

S441 ESTRO 38representative until next CBCT available fraction (as the figure shown).Recalculated dose was deformed into planning CT image by using deformable image registration from Velocity AI software version 3.2 to accumulate estimated actual dose in the treatment course.Dosimetric parameters were then studied, including V50, V60, V65, V70 and V75 for rectum and V65, V70, V75 and V80 for bladder based on QUANTEC study.Clinical toxicities of each case were reviewed from the patient records according to CTCAE version 5.0.Differences of mean volume between patients with grade 0-1 and grade 2-5 toxicities were compared using student T-test.Relationships between toxicities and volumes receiving doses were analyzed using logit analysis. ResultsAll patients with acute rectal toxicity grade 2 or more showed significant increase in volume receiving 50, 60, 65, 70, and 75 Gy radiation compared to those with acute rectal toxicity grade 0 and 1 (p=0.002,0.007, 0.008, 0.021, and 0.018 respectively), while in late rectal toxicity grade 2 or more showed significant increase in volume receiving 50, 60, 70 and 75Gy radiation compared to group with late rectal toxicity grade 0 and 1 (p=0.011,0.011, 0.011, 0.003 respectively).For the correlation between rectal volume receiving 75 Gy and acute and late toxicities, the significant dose-response relationships were exhibited (p<0.001).The probability for developing toxicities of 10%, 15% and 20% were related with volume receiving 75 Gy dose of 10.9, 15.7 and 19.3 cc in acute rectal toxicity and 10.9, 14.7 and 17.5 cc in late rectal toxicity.Acute and late bladder toxicity revealed no significant relationship with volume receiving radiation in all doses (65, 70, 75 and 80 Gy). ConclusionEstimated actual volume of rectum receiving high dose (V75) from CBCT-based recalculation was significantly related with grade 2-5 acute and late rectal toxicities in dose-response relationship.Adaptive planning should be considered for a novel approach in order to reduce toxicity.

Purpose: To assess the efficacy and safety of salvage stereotactic body radiation therapy (SBRT) in patients with biopsy-proven local prostate cancer recurrence after radiation therapy. Methods and Materials: Between April 2010 and January 2017, 100 patients were included in 7 centers. Disease extension was assessed by pelvic multiparametric magnetic resonance imaging and choline positron emission tomography in 87% and 94% of patients, respectively. The median time interval between the 2 treatments was 7.5 years (range, 2-18). Median prostate-specific antigen at recurrence was 4.3 ng/mL (range, 2-38). Median SBRT dose was 36 Gy (range, 25-36.25) in 6 fractions (range, 5-6), every other day. Thirty-four percent of patients were treated by androgen deprivation therapy for a median duration of 12 months. Toxicity was assessed according to Common Terminology Criteria for Adverse Events version 4.03. Results: Median follow-up was 29.3 months (range, 4-91). Second biochemical recurrence-free survival rate at 3 years was 55% (95% confidence interval [CI], 42%-66%). The initial D'Amico group, time interval after first radiation therapy, and SBRT dose were prognostic factors of biochemical recurrence-free survival in multivariate analysis (P = .09, P = .025, P = .018, respectively). No patient developed acute gastrointestinal toxicity of grade >1; rates of acute genitourinary toxicity of grade 2 and 3 were 8% and 1%, respectively. The actuarial 3-year grade >= 2 genitourinary and gastrointestinal toxicity was 20.8% (95% CI, 13%-29%) and 1% (95% CI, 0.1%-5.1%), respectively. One patient presented with neuritis of grade 3. Conclusions: With a short follow-up, this study shows that salvage SBRT allows for encouraging control and acceptable toxicity. Further prospective studies are necessary to confirm these preliminary results and to determine late toxicity. (C) 2019 Elsevier Inc. All rights reserved.

In radiotherapy, the treatment is adapted to each individual to protect healthy tissues but delivers most of time a standard dose according to the tumor histology and site. The only biomarkers studied to individualize the treatment are the HPV status with radiation dose de-escalation strategies, and tumor hypoxia with dose escalation to hypoxic subvolumes using FMISO-or FAZA-PET imaging. In the last decades, evidence has grown about the contribution of the immune system to radiation tumor response. Many preclinical studies have identified some of the mechanisms involved. In this context, we have realised a systematic review to highlight potential inflammatory and immune biomarkers of radiotherapy response. Some are inside the tumor microenvironment, as lymphocyte infiltration or PD-LI expression, others are circulating biomarkers, including different types of hematological cells, cytokines and chemokines. (C) Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.

NHL-ChirEx is an interprofessional cross-border education project that addresses the potential excess of radiation induced morbidity throughout the radiation planning and treatment process. NHL-ChirEx is supported by ESTRO and the University of the Greater Region and has been recently approved and funded under INTERREG VA Programme.

Purpose: Glioblastoma (GBM) remains an incurable disease despite extensive treatment with surgical resection, irradiation, and temozolomide. In line with many other forms of aggressive cancers, GBM is currently under consideration as a target for immunotherapy. However, GBM tends to be nonimmunogenic and exhibits a microenvironment with few or no effector T cells, a relatively low nonsynonymous somatic mutational load, and a low predicted neoantigen burden. GBM also exploits a multitude of immunosuppressive strategies. Methods and Materials: A number of immunotherapeutic approaches have been tested with disappointing results. A rationale exists to combine immunotherapy and radiation therapy, which can induce an immunogenic form of cell death with T-cell activation and tumor infiltration. Results: Various immunotherapy agents, including immune checkpoint modulators, transforming growth factor beta receptor inhibitors, and indoleamine-2,3-dioxygenase inhibitors, have been evaluated with irradiation in preclinical GBM models, with promising results, and are being further tested in clinical trials. Conclusions: This review aims to present the basic rationale behind this emerging complementary therapeutic approach in GBM, appraise the current preclinical and clinical data, and discuss the future challenges in improving the antitumor immune response.

Currently, there is no standard option for local salvage treatment for local prostate cancer recurrence after radiotherapy. Our objective was to investigate the feasibility and efficiency of Robotic Stereotactic Body Radiation Therapy (SBRT) in this clinical setting.

Cette étude avait pour objectif d’effectuer un suivi du taux de survenue des épidermites lors d’une irradiation mammaire, d’évaluer l’apport des huiles essentielles dans la prévention de celles-ci, ainsi que l’existence d’un lien entre le phénotype cutané et le risque d’épidermite radio-induite. Dans le cadre d’une étude observationnelle, toutes les patientes appliquaient sur le sein et les aires cutanées irradiées une crème contenant 5 % d’urée deux fois par jour. Celles qui le souhaitaient bénéficiaient en plus d’applications d’huiles essentielles (niaouli et lavande fine) deux fois par jour. Deux cohortes sont évaluées : crème à 5 % d’urée contre crème à 5 % d’urée et huiles essentielles. Des contraintes d’approvisionnement ont conduit à utiliser deux types de crème à 5 % d’urée (préparation magistrale ou préparation commerciale Eucerin®). L’influence du type de crème à l’urée a été étudiée. L’indicateur de résultat était la survenue d’une épidermites de grade 2 ou plus, observées lors de la dernière séance d’irradiation. Sur 637 patientes incluses, 366 (57 %) ont choisi l’option d’application d’huiles essentielles. En ce qui concerne l’application d’huiles essentielles, 15,3 % des patientes de la cohorte appliquant la crème à l’urée et les huiles essentielles avaient une épidermite, contre 19,9 % dans la cohorte appliquant seulement la crème à l’urée. Pour ce qui concerne le type de crème à l’urée : 12,8 % d’épidermites ont été observées avec l’emploi de la préparation magistrale contre 21,9 % avec le produit commercial. Pour ce qui concerne le volume mammaire : le taux de survenue des épidermites augmentait avec celui-ci (moins de 700 cm3 : 8 % ; 700 à 1300 cm3 : 28 % ; plus de1300 cm3 : 53 %). Pour ce qui concerne le phénotype cutané : il n’y avait pas de différence significative sur l’incidence et/ou le grade des épidermites (19, 16 et 23 % selon que la peau était claire, intermédiaire ou foncée). Même si l’incidence des épidermites est de moins de 4,6 % avec le recours aux huiles essentielles, cette étude ne permet pas de conclure à un effet protecteur. Il a été observé un effet favorable de la préparation magistrale de la crème à l’urée, par rapport à la préparation commerciale (diminution de 42 % des épidermites). Le phénotype cutané n’a pas eu de réelle influence sur l’apparition des épidermites radio-induites.

L’irradiation en conditions stéréotaxiques de la prostate peut provoquer un œdème local par activation du processus inflammatoire. Cet œdème conduit à une augmentation de l’espace entre les repères fiduciels implantées dans la prostate et est à l’origine de l’accroissement du paramètre « corps rigide » mesuré par le robot lors du tracking. Dans cette hypothèse, les corticoïdes pourraient réduire ce phénomène. Cette étude a donc évalué les variations du paramètre « corps rigide » au cours du traitement, permettant d’objectiver l’impact d’une corticothérapie en cas d’accroissement significatif des valeurs. Un recrutement prospectif et consécutif de mars à novembre 2016 a concerné les patients traités par CyberKnife® pour un adénocarcinome de prostate, à une dose de 36 à 37,5 Gy, en cinq à six fractions, à raison de trois fractions par semaine. Les valeurs du paramètre « corps rigide » ont été colligées au cours des séances de traitement. Une dose quotidienne de 32 mg de méthylprednisolone a été prescrite lorsque le paramètre « corps rigide » dépassait la valeur seuil de 2 mm. Le test t de Student pour cas appariés a été utilisé pour étudier les modifications de valeurs du paramètre « corps rigide ». Sur 35 patients, 12 (34 %) ont été placés sous corticoïdes entre la deuxième et la troisième séance de traitement (2,92 ± 0,5), suite à une augmentation de 89 % des valeurs du paramètre « corps rigide » (p < 0,002) et au dépassement du seuil de 2 mm. Dès la séance suivante, une réduction de 38 % des valeurs du paramètre « corps rigide » (p < 0,001) a été observée, les ramenant systématiquement sous le seuil de tolérance d’au plus 1,5 mm. L’étude de la population sans corticoïdes n’a montré aucune variation significative des valeurs du paramètre « corps rigide » (p = 0,29) au cours des séances. Un traitement prostatique par CyberKnife® induit chez 34 % des patients un œdème qui augmente significativement les valeurs du paramètre « corps rigide », induisant un risque d’imprécision pour la réalisation de l’irradiation. L’utilisation d’une corticothérapie à dose modérée réduit significativement ce phénomène, permettant de réaliser le traitement en respectant le critère optimal de précision, soit une valeur du paramètre « corps rigide » inférieure ou égale à 1,5 mm.

Purpose Dose escalation may improve curability in intermediate-risk prostate carcinoma. A multicenter national program was developed to assess toxicity and tumor response with hypofractionated stereotactic boost after conventional radiotherapy in intermediate-risk prostate cancer. Methods and material Between August 2010 and April 2013, 76 patients with intermediated-risk prostate carcinoma were included in the study. A first course delivered 46 Gy by IMRT (68.4% of patients) or 3D conformal radiotherapy (31.6% of patients). The second course delivered a boost of 18 Gy (3x6Gy) within 10 days. Gastrointestinal (GI) and genitourinary (GU) toxicities were evaluated as defined by NCI-CTCAE (v4.0). Secondary outcome measures were local control, overall and metastasis-free survival, PSA kinetics, and patient functional status (urinary and sexual) according to the IIEF5 and IPSS questionnaires. Results The overall treatment time was 45 days (median, range 40–55). Median follow-up was 26.4 months (range, 13.6–29.9 months). Seventy-seven per cent (n = 58) of patients presented a Gleason score of 7. At 24 months, biological-free survival was 98.7% (95% CI, 92.8–99.9%) and median PSA 0.46 ng/mL (range, 0.06–6.20 ng/mL). Grade ≥2 acute GI and GU toxicities were 13.2% and 23.7%, respectively. Grade ≥2 late GI and GU toxicities were observed in 6.6% and 2.6% of patients, respectively. No grade 4 toxicity was observed. Conclusions Hypofractionated stereotactic boost is effective and safely delivered for intermediate-risk prostate carcinoma after conventional radiation. Mild-term relapse-free survival and tolerance results are promising, and further follow-up is warranted to confirm the results at long term. Trial registration ClinicalTrials.gov NCT01596816.

Purpose: To evaluate the efficacy and tolerance of adjuvant concurrent chemoradiation (CCRT) as treatment of grade 2 and 3 (G2-3) localized extremity soft tissue sarcomas (STS) by comparing CCRT with standard adjuvant radiation therapy (RT). Patients and methods: This monocentric retrospective study included non-pediatric patients (>16 years) treated by adjuvant RT with or without chemotherapy (CT) after conservative resection of non recurrent G2-3 extremity STS. Results: A total of 80 patients were treated between 1990 and 2012: 51 by RT and 29 by CCRT. Of the 29 CCRT patients, 25 received doxorubicin monotherapy (75 mg/m(2)/3 weeks). The CCRT group contained a greater proportion of grade 3 extremity STS (p < 0.001). Median follow up was 68 months (9-284). Multivariate analysis revealed greater local control in the CCRT group (1 local recurrence vs 8 in the RT group; HR = 0.082, 95% CI 0.011-0.321) and incomplete resection as the major risk factor of local recurrence (HR = 25.2, 95% CI 4.767-133.226). The two groups exhibited no differences in distant failure-free survival (HR = 1.469, 95% CI 0.668-3.228), disease-free survival (HR = 1.096, 95% CI 0.519-2.315) or overall survival (HR = 1.378, 95% CI 0.498-3.814). Grade 3 was an adverse prognostic factor for overall survival (HR = 3.11, 95% CI 1.04-9.32). Our analyses also revealed that CCRT tended to increase the risk of both grade >= 3 acute dermatitis (14 events vs 6 in the RT group; OR = 6.99, 95% CI 2.28-21.47) and grade >= 2 late toxicity (6 events vs 3 in the RT group; p= 0.0572). Conclusion: CCRT could improve local control as part of a limb-preservation strategy. However, with a limited number of patients, CCRT showed no improvement in either distant control or survival and increased toxicity. (C) 2017 Elsevier B.V. All rights reserved.

Novel paradigms emerge in oncology today. Systemic treatments are more effective and diversified along with an increased life expectancy in oligometastatic patients. Stereotactic radiotherapy using hypo fractionation opens new perspectives for local tumour control. The area of radiobiology has expanded with integration of tumour microenvironment in which radiation-induced inflammation mediators and immune system play a major role. Immunity checkpoints inhibitors experience a major development. This rapidly evolving field seems involved in the abscopal effects, especially when radiation is combined with checkpoints inhibitors, as demonstrated in numerous preclinical studies and several clinical trials. Paradoxically, irradiation also produces immunosuppressive effects. This manuscript aims to report the dual effects of ionizing radiation on the immune system and reviews some results of the combination of radiation and immunity chekpoints inhibitors and also research perspectives. (C) 2017 Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.

De nouveaux concepts se distinguent aujourd’hui en cancérologie. Les traitements systémiques sont plus efficaces et plus variés, l’espérance de vie s’allonge en phase métastatique avec émergence de la maladie oligométastatique. La radiothérapie stéréotaxique à fortes doses par fraction se développe et représente une nouvelle arme permettant d’assurer le contrôle tumoral local. La sphère de la radiobiologie s’est élargie avec intégration du microenvironnement tumoral au sein duquel les médiateurs de l’inflammation et les cellules immunitaires jouent un rôle majeur après une irradiation. Les inhibiteurs des checkpoints de l’immunité connaissent un fort développement. Ainsi, l’immunité antitumorale connaît un formidable renouveau et semble impliquée dans l’effet abscopal observé après irradiation, notamment en cas d’association radiothérapie et inhibiteurs des checkpoints, comme l’ont montré de nombreuses études précliniques et plusieurs essais cliniques précoces. Paradoxalement, l’irradiation génère également des effets immunosuppresseurs. Cette revue a pour objectif de faire le point sur les effets antagonistes de l’irradiation sur l’immunité antitumorale, d’exposer certaines données concernant les associations de radiothérapie et d’inhibiteurs des checkpoints de l’immunité et soulever certaines inconnues ouvrant de nouveaux travaux de recherche.