Robustness of radiomics features on 0.35 T magnetic resonance imaging for magnetic resonance-guided radiotherapy.

Background and purpose: MR-guided radiotherapy adds the precision of magnetic resonance imaging (MRI) to the therapeutic benefits of a linear accelerator. Prior to each therapeutic session, an MRI generates a significant volume of imaging data ripe for analysis. Radiomics stands at the forefront of medical imaging and oncology research, dedicated to mining quantitative imaging attributes to forge predictive models. However, the robustness of these models is often challenged. Materials and methods: To assess the robustness of feature extraction, we conducted reproducibility studies using a 0.35 T MR-linac system, employing both a specialized phantom and patient-derived images, focusing on cases of pancreatic cancer. We extracted shape-based, first-order and textural features from patient-derived images and only first-order and textural features from phantom-derived images. The impact of the delay between simulation and first fraction images was also assessed with an equivalence test. Results: From 107 features evaluated, 58 (54 %) were considered as non-reproducible: 18 were uniformly inconsistent across both phantom and patient images, 9 were specific to phantom-based analysis, and 31 to patient-derived data. Conclusion: Our findings show that a significant proportion of radiomic features extracted from this dual dataset were unreliable. It is essential to discard these non-reproducible elements to refine and enhance radiomic model development, particularly for MR-guided radiotherapy in pancreatic cancer.

Association of Radiochemotherapy to Immunotherapy in unresectable locally advanced Oesophageal carciNoma-randomized phase 2 trial ARION UCGI 33/PRODIGE 67: the study protocol.

BACKGROUND: In case of locally advanced and/or non-metastatic unresectable esophageal cancer, definitive chemoradiotherapy (CRT) delivering 50 Gy in 25 daily fractions in combination with platinum-based regimen remains the standard of care resulting in a 2-year disease-free survival of 25% which deserves to be associated with new systemic strategies. In recent years, several immune checkpoint inhibitors (anti-PD1/anti-PD-L1, anti-Program-Death 1/anti-Program-Death ligand 1) have been approved for the treatment of various solid malignancies including metastatic esophageal cancer. As such, we hypothesized that the addition of an anti-PD-L1 to CRT would provide clinical benefit for patients with locally advanced oesophageal cancer. To assess the efficacy of the anti-PD-L1 durvalumab in combination with CRT and then as maintenance therapy we designed the randomized phase II ARION (Association of Radiochemotherapy with Immunotherapy in unresectable Oesophageal carciNoma- UCGI 33/PRODIGE 67). METHODS: ARION is a multicenter, open-label, randomized, comparative phase II trial. Patients are randomly assigned in a 1:1 ratio in each arm with a stratification according to tumor stage, histology and centre. Experimental arm relies on CRT with 50 Gy in 25 daily fractions in combination with FOLFOX regimen administrated during and after radiotherapy every two weeks for a total of 6 cycles and durvalumab starting with CRT for a total of 12 infusions. Standard arm is CRT alone. Use of Intensity Modulated radiotherapy is mandatory. The primary endpoint is to increase progression-free survival at 12 months from 50 to 68% (HR = 0.55) (power 90%; one-sided alpha-risk, 10%). Progression will be defined with central external review of imaging. ANCILLARY STUDIES ARE PLANNED: PD-L1 Combined Positivity Score on carcinoma cells and stromal immune cells of diagnostic biopsy specimen will be correlated to disease free survival. The study of gut microbiota will aim to determine if baseline intestinal bacteria correlates with tumor response. Proteomic analysis on blood samples will compare long-term responder after CRT with durvalumab to non-responder to identify biomarkers. CONCLUSION: Results of the present study will be of great importance to evaluate the impact of immunotherapy in combination with CRT and decipher immune response in this unmet need clinical situation. TRIAL REGISTRATION: ClinicalTrials.gov, NCT: 03777813.Trial registration date: 5th December 2018.

A prospective registry study of stereotactic magnetic resonance guided radiotherapy (MRgRT) for primary liver tumors.

BACKGROUND AND PURPOSE: Stereotactic body radiation therapy (SBRT) has demonstrated safe and effective results for primary liver tumors. Magnetic Resonance guided Radiotherapy (MRgRT) is an innovative radiotherapy modality for abdominal tumors. The aim of this study is to report on acute and late toxicities and initial oncological results for primary liver tumors treated with MRgRT. MATERIALS AND METHODS: We prospectively included in our cohort all patients treated by MRgRT for a primary liver tumor at the Montpellier Cancer Institute. The primary endpoint was acute and late toxicities assessed according to CTCAE v 5.0. The mean prescribed dose was 50 Gy in 5 fractions. RESULTS: Between October 2019 and April 2022, MRgRT treated 56 patients for 72 primary liver lesions. No acute or late toxicities of CTCAE grade greater than 2 attributable to radiotherapy were noted during follow-up. No cases of radiation-induced liver disease (RILD), either classical or non-classical, occurred. After a median follow-up of 13.2 months (95% CI [8.8; 15.7]), overall survival was 85.1% (95% CI: [70.8; 92.7]) at 1 year and 74.2% at 18 months (95% CI [52.6; 87.0]). Local control was 98.1% (95% CI: [87.4; 99.7]) and 94.7% (95% CI: [79.5; 98.7]) at 12 and 18 months, respectively. Among the HCC subgroup, no local recurrences were observed. CONCLUSION: MRgRT for primary liver tumors is safe without severe adverse events and reach excellent local control. Numerous studies are underway to better assess the value of MRI guidance and adaptive process in these indications.

Implementation of the Calypso system: a commissioning experience.

Background: The aim of this study was to describe the clinical implementation of the Calypso system with its potential impact on the treatment delivery. Materials and methods: The influence of the electromagnetic array was investigated on the kilovoltage cone beam computed tomography (kV-CBCT) image quality using the CATPHAN 504 CBCT images. Then, the QFix kVue Calypso couch top and the array attenuation, and their dosimetric influence on the Volumetric modulated arc therapy (VMAT) treatments of prostate was evaluated. Results: Regarding the image quality, a significant increase of noise (p < 0.01) was detected with the array in place, resulting in a significant decrease in signal noise ratio (SNR) (p < 0.01). No difference in absolute contrast was observed. Finally, there was a significant decrease in contrast noise ratio (CNR) (p < 0.01) even if the deviation was only of 2.5%. For the dosimetric evaluation, the maximum attenuation of the couch was 12.02% and 13.19% for X6 and X6 flattening filter free (FFF), respectively (configuration of rails out). Besides, the mean attenuation of the array was 1.15% and 1.67% for X6 and X6 FFF, respectively. For the VMAT treatment plans, the mean dose was reduced by 0.61% for X6 and by 0.31% for X6 FFF beams when using the electromagnetic array. Conclusions: The Calypso system does not affect significantly the kV-CBCT image quality and the VMAT plan dose distribution.

Stereotactic MR-Guided Radiotherapy for Liver Metastases: First Results of the Montpellier Prospective Registry Study.

Liver stereotactic body radiotherapy (SBRT) is a local treatment that provides good local control and low toxicity. We present the first clinical results from our prospective registry of stereotactic MR-guided radiotherapy (MRgRT) for liver metastases. All patients treated for liver metastases were included in this prospective registry study. Stereotactic MRgRT indication was confirmed by multidisciplinary specialized tumor boards. The primary endpoints were acute and late toxicities. The secondary endpoints were survival outcomes (local control, overall survival (OS), disease-free survival, intrahepatic relapse-free survival). Twenty-six consecutive patients were treated for thirty-one liver metastases between October 2019 and April 2022. The median prescribed dose was 50 Gy (40-60) in 5 fractions. No severe acute MRgRT-related toxicity was noted. Acute and late gastrointestinal and liver toxicities were low and mostly unrelated to MRgRT. Only 5 lesions (16.1%) required daily adaptation because of the proximity of organs at risk (OAR). With a median follow-up time of 17.3 months since MRgRT completion, the median OS, 1-year OS and 2-year OS rates were 21.7 months, 83.1% (95% CI: 55.3-94.4%) and 41.6% (95% CI: 13.5-68.1%), respectively, from MRgRT completion. The local control at 6 months, 1 year and 2 years was 90.9% (95% CI: 68.3-97.7%). To our knowledge, we report the largest series of stereotactic MRgRT for liver metastases. The treatment was well-tolerated and achieved a high LC rate. Distant relapse remains a challenge in this population.

Clinical adoption patterns of 0.35 Tesla MR-guided radiation therapy in Europe and Asia.

BACKGROUND: Magnetic resonance-guided radiotherapy (MRgRT) utilization is rapidly expanding, driven by advanced capabilities including better soft tissue imaging, continuous intrafraction target visualization, automatic triggered beam delivery, and the availability of on-table adaptive replanning. Our objective was to describe patterns of 0.35 Tesla (T)-MRgRT utilization in Europe and Asia among early adopters of this novel technology. METHODS: Anonymized administrative data from all 0.35T-MRgRT treatment systems in Europe and Asia were extracted for patients who completed treatment from 2015 to 2020. Detailed treatment information was analyzed for all MR-linear accelerators (linac) and -cobalt systems. RESULTS: From 2015 through the end of 2020, there were 5796 completed treatment courses delivered in 46,389 individual fractions. 23.5% of fractions were adapted. Ultra-hypofractionated (UHfx) dose schedules (1-5 fractions) were delivered for 63.5% of courses, with 57.8% of UHfx fractions adapted on-table. The most commonly treated tumor types were prostate (23.5%), liver (14.5%), lung (12.3%), pancreas (11.2%), and breast (8.0%), with increasing compound annual growth rates (CAGRs) in numbers of courses from 2015 through 2020 (pancreas: 157.1%; prostate: 120.9%; lung: 136.0%; liver: 134.2%). CONCLUSIONS: This is the first comprehensive study reporting patterns of utilization among early adopters of a 0.35T-MRgRT system in Europe and Asia. Intrafraction MR image-guidance, advanced motion management, and increasing adoption of on-table adaptive RT have accelerated a transition to UHfx regimens. MRgRT has been predominantly used to treat tumors in the upper abdomen, pelvis and lungs, and increasingly with adaptive replanning, which is a radical departure from legacy radiotherapy practices.

Magnetic Resonance-Guided Reirradiation for Local Recurrence within the Prostate or in the Prostate Bed: One-Year Clinical Results of a Prospective Registry Study.

Around 33% of patients treated by EBRT or brachytherapy will present a biochemical recurrence. SBRT is a new option for the treatment of patients with local-only recurrence. MRgRT seems to be interesting for the treatment of these recurrences. This article presents the one-year late tolerance and biochemical recurrence-free survival results of a prospective registry study. Patients with intraprostatic (or in the prostate bed) recurrence were treated with 5 to 9 fractions (median dose of 30 Gy in 5 fractions) with the MRIdian® system. PSA level and toxicities were evaluated before treatment and at three, six and 12 months after treatment. Thirty-seven patients with a median age of 74.5 years old were treated between 21 October 2019 and 7 December 2020. Acute tolerance was excellent with no grade >2 toxicities. Twelve months after treatment, we observed an increase of grade 1−2 dysuria (46% vs. 13% before treatment) and grade 1 polyuria (73% vs. 7%). The six, nine and 12-months biochemical-recurrence free survival were 97.3%, 86.5% and 65.0%. Fifteen patients (40%) presented a biochemical recurrence. Nine of these 15 patients (60%) had a persistent disease within the treated volume. In conclusion, MRgRT is safe and has promising survival results.

Stereotactic MR-Guided Radiotherapy for Pancreatic Tumors: Dosimetric Benefit of Adaptation and First Clinical Results in a Prospective Registry Study.

Introduction: Stereotactic MR-guided adaptive radiotherapy (SMART) is an attractive modality of radiotherapy for pancreatic tumors. The objectives of this prospective registry study were to report the dosimetric benefits of daily adaptation of SMART and the first clinical results in pancreatic tumors. Materials and Methods: All patients treated in our center with SMART for a pancreatic tumor were included. Patients were planned for five daily-adapted fractions on consecutive days. Endpoints were acute toxicities, late toxicities, impact of adaptive treatment on target volume coverage and organs at risk (OAR) sparing, local control (LC) rate, distant metastasis-free survival (DMFS), and overall survival (OS). Results: Thirty consecutive patients were included between October 2019 and April 2021. The median dose prescription was 50 Gy. No patient presented grade > 2 acute toxicities. The most frequent grade 1-2 toxicities were asthenia (40%), abdominal pain (40%), and nausea (43%). Daily adaptation significantly improved planning target volume (PTV) and gross tumor volume (GTV) coverage and OAR sparing. With a median follow-up of 9.7 months, the median OS, 6-month OS, and 1-year OS were 14.1 months, 89% (95% CI: 70%-96%), and 75% (95% CI: 51%-88%), respectively, from SMART completion. LC at 6 months and 1 year was respectively 97% (95% CI: 79-99.5%) and 86% (95% CI: 61%-95%). There were no grade > 2 late toxicities. With a median follow-up of 10.64 months, locally advanced pancreatic cancer (LAPC) and borderline resectable pancreatic cancer (BRPC) patients (22 patients) had a median OS, 6-month OS, and 1-year OS from SMART completion of 14.1 months, 76% (95% CI: 51%-89%), and 70% (95% CI: 45%-85%), respectively. Nine patients underwent surgical resection (42.1% of patients with initial LAPC and 33.3% of patients with BRPC), with negative margins (R0). Resected patients had a significantly better OS as compared to unresected patients (p = 0.0219, hazard ratio (HR) = 5.78 (95% CI: 1.29-25.9)). Conclusion: SMART for pancreatic tumors is feasible without limiting toxicities. Daily adaptation demonstrated a benefit for tumor coverage and OAR sparing. The severity of observed acute and late toxicities was low. OS and LC rates were promising. SMART achieved a high secondary resection rate in LAPC patients. Surgery after SMART seemed to be feasible and might increase OS in these patients.

Stereotactic MR-Guided Adaptive Radiotherapy for Pancreatic Tumors: Updated Results of the Montpellier Prospective Registry Study.

Introduction: Stereotactic MR-guided Adaptive RadioTherapy (SMART) is a novel process to treat pancreatic tumors. We present an update of the data from our prospective registry of SMART for pancreatic tumors. Materials and methods: After the establishment of the SMART indication in a multidisciplinary board, we included all patients treated for pancreatic tumors. Primary endpoints were acute and late toxicities. Secondary endpoints were survival outcomes (local control, overall survival, distant metastasis free survival) and dosimetric advantages of adaptive process on targets volumes and OAR. Results: We included seventy consecutive patients in our cohort between October 2019 and April 2022. The prescribed dose was 50 Gy in 5 consecutive fractions. No severe acute SMART related toxicity was noted. Acute and late Grade ≤ 2 gastro intestinal were low. Daily adaptation significantly improved PTV and GTV coverage as well as OAR sparing. With a median follow-up of 10.8 months since SMART completion, the median OS, 6-months OS, and 1-year OS were 20.9 months, 86.7% (95% CI: (75−93%), and 68.6% (95% CI: (53−80%), respectively, from SMART completion. Local control at 6 months, 1 year, and 2 years were, respectively, 96.8 % (95% CI: 88−99%), 86.5 (95% CI: 68−95%), and 80.7% (95% CI: 59−92%). There was no grade > 2 late toxicities. Locally Advanced Pancreatic Cancers (LAPC) and Borderline Resectable Pancreatic Cancers (BRPC) patients (52 patients) had a median OS, 6-months OS, and 1-year OS from SMART completion of 15.2 months, 84.4% (95% CI: (70−92%)), and 60.5% (95% CI: (42−75%)), respectively. The median OS, 1-year OS, and 2-year OS from initiation of induction chemotherapy were 22.3 months, 91% (95% CI: (78−97%)), and 45.8% (95% CI: (27−63%)), respectively. Twenty patients underwent surgical resection (38.7 % of patients with initially LAPC) with negative margins (R0). Conclusion: To our knowledge, this is the largest series of SMART for pancreatic tumors. The treatment was well tolerated with only low-grade toxicities. Long-term OS and LC rates were achieved. SMART achieved high secondary resection rates in LAPC patients.

Stereotactic MR-Guided Radiotherapy for Adrenal Gland Metastases: First Clinical Results.

Stereotactic MR-guided Radiotherapy (MRgRT) is an interesting treatment option for adrenal gland metastases (AGM). We reviewed data from 12 consecutive patients treated with MRgRT for an AGM in our center between 14 November 2019 and 17 August 2021. Endpoints were tolerance assessment, the impact of adaptive treatment on target volume coverage and organs at risk (OAR) sparing, local control (LC), and overall survival (OS). The majority of patients were oligometastatic (58.3%), with 6 right AGM, 5 left AGM and 1 left and right AGM. The prescribed dose was 35 to 50 Gy in 3 to 5 fractions. The median PTV V95% on the initial plan was 95.74%. The median V95% of the PTVoptimized (PTVopt) on the initial plan was 95.26%. Thirty-eight (69%) fractions were adapted. The PTV coverage was significantly improved for adapted plans compared to predicted plans (median PTV V95% increased from 89.85% to 91.17%, p = 0.0478). The plan adaptation also significantly reduced Dmax for the stomach and small intestine. The treatment was well tolerated with no grade > 2 toxicities. With a median follow-up of 15.5 months, the 1−year LC and OS rate were 100% and 91.7%. Six patients (50%) presented a metastatic progression, and one patient (8.3%) died of metastatic evolution during the follow-up. Adaptation of the treatment plan improved the overall dosimetric quality of MRI-guided radiotherapy. A longer follow-up is required to assess late toxicities and clinical results.

Image-Guided Liver Stereotactic Body Radiotherapy Using VMAT and Real-Time Adaptive Tumor Gating: Evaluation of the Efficacy and Toxicity for Hepatocellular Carcinoma.

Liver SBRT is a therapeutic option for the treatment of HCC in patients not eligible for other local therapies. We retrospectively report the outcomes of a cohort of consecutive patients treated with SBRT for HCC at the Montpellier Cancer Institute. Between March 2013 and December 2018, 66 patients were treated with image-guided liver SBRT using VMAT and real-time adaptive tumor gating in our institute. The main endpoints considered in this study were local control, disease-free survival, overall survival, and toxicity. The median follow-up was 16.8 months. About 66.7% had prior liver treatment. Most patients received 50 Gy in five fractions of 10 Gy. No patient had local recurrence. Overall survival and disease-free survival were, respectively, 83.9% and 46.7% at one year. In multivariate analysis, the diameter of the lesions was a significant prognostic factor associated with disease-free survival (HR = 2.57 (1.19-5.53) p = 0.02). Regarding overall survival, the volume of PTV was associated with lower overall survival (HR = 2.84 (1.14-7.08) p = 0.025). No grade 3 toxicity was observed. One patient developed a grade 4 gastric ulcer, despite the dose constraints being respected. Image-guided liver SBRT with VMAT is an effective and safe treatment in patients with inoperable HCC, even in heavily pre-treated patients. Further prospective evaluation will help to clarify the role of SBRT in the management of HCC patients.

Magnetic Resonance-Guided Reirradiation for Local Recurrence Within the Prostate or in the Prostate Bed: Preliminary Results of a Prospective Registry Study.

PURPOSE: This prospective registry study evaluated the feasibility of stereotactic magnetic resonance imaging (MRI)-guided radiation therapy for the local treatment of isolated prostate cancer recurrence within the gland or prostate bed after primary radiation therapy. METHODS AND MATERIALS: Patients with isolated recurrence without any regional or distant extension after treatment by external radiation therapy of the prostate gland/bed or by prostate brachytherapy were included. A 173-second Fast Imaging with Steady state Precession (TrueFISP) sequence was used for MRI simulation, and the gross tumor volume was delineated using multimodal images. The initial treatment plan varied from 27.5 Gy in 5 fractions to 38.7 Gy in 9 fractions and was adapted at each session, if necessary. The primary endpoint was acute toxicities (according to the Common Terminology Criteria for Adverse Events v5.0 criteria). Secondary endpoints were the effects of the adaptive treatment on target volume coverage, late toxicities, and oncologic events. RESULTS: Twenty patients were included. After a minimum follow-up of 6 months, grade 2 dysuria (from grade 1 at baseline; n = 1), grade 2 polyuria (n = 1), grade 1 urinary incontinence (n = 1), grade 1 urinary pain (n = 2), and grade 1 diarrhea (n = 1) were reported.All initial treatment plans met the tumor coverage objectives, with a mean 95% planning target volume value of 95.7%. No plan exceeded the bladder and rectum dose constraints, but 8 exceeded the urethra dose constraints because of urethra proximity to the planning target volume. The initial plan was adapted in 7 patients (35%). The tumor coverage improved by 3.7% compared with the predicted plan (P = .0001) without increase in the dose to organs at risk. The biochemical control rate for the whole cohort was 75% (15/20 patients) including the 4 patients who received androgen-deprivation therapy. CONCLUSIONS: MRI-guided reirradiation for isolated recurrence within the prostate or in the prostate bed appears to be safe with excellent dosimetric results.

Recommendations for planning and delivery of radical radiotherapy for localized urothelial carcinoma of the bladder.

PURPOSE: Curative radio-chemotherapy is recognized as a standard treatment option for muscle-invasive bladder cancer (MIBC). Nevertheless, the technical aspects for MIBC radiotherapy are heterogeneous with a lack of practical recommendations. METHODS AND MATERIALS: In 2018, a workshop identified the need for two cooperative groups to develop consistent, evidence-based guidelines for irradiation technique in the delivery of curative radiotherapy. Two radiation oncologists performed a review of the literature addressing several topics relative to radical bladder radiotherapy: planning computed tomography acquisition, target volume delineation, radiation schedules (total dose and fractionation) and dose delivery (including radiotherapy techniques, image-guided radiotherapy (IGRT) and adaptive treatment modalities). Searches for original and review articles in the PubMed and Google Scholar databases were conducted from January 1990 until March 2020. During a meeting conducted in October 2020, results on 32 topics were presented and discussed with a working group involving 15 radiation oncologists, 3 urologists and one medical oncologist. We applied the American Urological Association guideline development's method to define a consensus strategy. RESULTS: A consensus was obtained for all 34 except 4 items. The group did not obtain an agreement on CT enhancement added value for planning, PTV margins definition for empty bladder and full bladder protocols, and for pelvic lymph-nodes irradiation. High quality evidence was shown in 6 items; 8 items were considered as low quality of evidence. CONCLUSION: The current recommendations propose a homogenized modality of treatment both for routine clinical practice and for future clinical trials, following the best evidence to date, analyzed with a robust methodology. The XXX group formulates practical guidelines for the implementation of innovative techniques such as adaptive radiotherapy.

Long-term follow-up experience in anal canal cancer treated with Intensity-Modulated Radiation Therapy: Clinical outcomes, patterns of relapse and predictors of failure.

BACKGROUND AND PURPOSE: To assess the long-term outcomes of patients with squamous cell carcinoma of the anal canal (SCCAC) treated with Intensity-Modulated Radiation Therapy (IMRT). MATERIAL AND METHODS: From 2007 to 2015, 193 patients were treated by IMRT for SCCAC. Radiotherapy delivered 45 Gy in 1.8 Gy daily-fractions to the primary tumor and elective nodal areas, immediately followed by a boost of 14.4-20 Gy to the primary tumor and involved nodes. Concurrent chemotherapy with 5-FU-mitomycin (MMC) or cisplatin was added for locally advanced tumors. Survivals were estimated by Kaplan-Meier method. Locoregional (LR) relapses were precisely assessed. Prognostic factors were evaluated by uni- and multivariate analyses. Late toxicity was scored according to the Common Toxicity Criteria for Adverse Events v4.0. RESULTS: Median follow-up was 70 months (range, 1-131). Forty-nine men (25%) and 144 women (75%) were analyzed. Median age was 62 years. Tumor stages were I, II, III and IV in 7%, 24%, 63% and 6% of cases, respectively. Chemotherapy was delivered in 167 patients (87%), mainly MMC (80%). Five-year OS, DFS, CFS and LR control rates were 74%, 68%, 66% and 85%, respectively. Forty-one patients (21%) had a relapse: 22 were LR, mostly in-field (68%). Predictors for LR failure were exclusive radiotherapy, chemotherapy lacking MMC and treatment breaks >3 days. Overall late toxicity ≥grade 2 occurred in 43% of patients, with 24% grade 3 and one case of grade 4 (hematuria). CONCLUSION: CRT with IMRT assures excellent local control in locally advanced SCCAC with manageable long-term toxicity. Multicentric prospective trials are required to reinforce those results.

MRI in medical practice and its future use in radiation oncology. Resume of XXV GOCO Congress (Montpellier) 2017.

This publication is a resume of the GOCO Congress (Montpellier 2017). A part of this congress was about the use of MRI in clinical practice, focused on the oncology field. The role of this tool was described in diagnosis, staging of tumors, evaluation of treatment response and the future use in prognostic and investigation (radiomics). After that, in the context of the present and future uses of MRI in radiation oncology, MRI guided radiotherapy was explained, as a method that allows an increased precision in image guided treatments. This publication is a resume of the GOCO Congress (Montpellier 2017). A part of this congress was about the use of MRI in clinical practice, focused on the oncology field. The role of this tool was described in diagnosis, staging of tumors, evaluation of treatment response and the future use in prognostic and investigation (radiomics).

Tracking, gating, free-breathing, which technique to use for lung stereotactic treatments? A dosimetric comparison.

BACKGROUND: The management of breath-induced tumor motion is a major challenge for lung stereotactic body radiation therapy (SBRT). Three techniques are currently available for these treatments: tracking (T), gating (G) and free-breathing (FB). AIM: To evaluate the dosimetric differences between these three treatment techniques for lung SBRT. MATERIALS AND METHODS: Pretreatment 4DCT data were acquired for 10 patients and sorted into 10 phases of a breathing cycle, such as 0% and 50% phases defined respectively as the inhalation and exhalation maximum. GTVph, PTVph (=GTVph + 3 mm) and the ipsilateral lung were contoured on each phase.For the tracking technique, 9 fixed fields were adjusted to each PTVph for the 10 phases. The gating technique was studied with 3 exhalation phases (40%, 50% and 60%). For the free-breathing technique, ITVFB was created from a sum of all GTVph and a 3 mm margin was added to define a PTVFB. Fields were adjusted to PTVFB and dose distributions were calculated on the average intensity projection (AIP) CT. Then, the beam arrangement with the same monitor units was planned on each CT phase.The 3 modalities were evaluated using DVHs of each GTVph, the homogeneity index and the volume of the ipsilateral lung receiving 20 Gy (V 20Gy). RESULTS: The FB system improved the target coverage by increasing D mean (75.87(T)-76.08(G)-77.49(FB)Gy). Target coverage was slightly more homogeneous, too (HI: 0.17(T and G)-0.15(FB)). But the lung was better protected with the tracking system (V 20Gy: 3.82(T)-4.96(G)-6.34(FB)%). CONCLUSIONS: Every technique provides plans with a good target coverage and lung protection. While irradiation with free-breathing increases doses to GTV, irradiation with the tracking technique spares better the lung but can dramatically increase the treatment complexity.

Impact of adjuvant hormonotherapy on radiation-induced breast fibrosis according to the individual radiosensitivity: results of a multicenter prospective French trial.

BACKGROUND: To evaluate risk of severe breast fibrosis occurrence in patients treated by breast-conserving surgery, adjuvant radiotherapy and hormonotherapy (HT) according to individual radiosensitivity (RILA assay). RESULTS: HT- and RILAhigh were the two independent factors associated with improved breast-fibrosis free survival (BFFS). BFFS rate at 36 months was lower in patients with RILAlow and HT+ than in patients with RILAhigh and HT- (75.8% and 100%, respectively; p = 0.004, hazard ratio 5.84 [95% confidence interval (CI) 1.8-19.1]). Conversely, BFFS at 36 months was comparable in patients with RILAhigh and HT+ and in patients with RILAlow and HT- (89.8% and 93.5%, respectively; p = 0.39, hazard ratio 1.7 [95% CI 0.51-5.65]), showing that these two parameters influenced independently the occurrence of severe breast fibrosis. BFFS rate was not affected by the HT type (tamoxifen or aromatase inhibitor) and timing (concomitant or sequential with radiotherapy). CONCLUSIONS: HT and RILA score independently influenced BFFS rate at 36 months. Patients with RILAhigh and HT- presented an excellent BFFS at 36 months (100%). MATERIALS AND METHODS: Breast Fibrosis-Free Survival (BFFS) rate was assessed relative to RILA categories and to adjuvant HT use (HT+ and HT-, respectively) in a prospective multicentre study (NCT00893035) which enrolled 502 breast cancer patients (456 evaluable patients). Breast fibrosis was recorded according to CTCAE v3.0 grading scale; RILA score was defined according to two categories (<12%: RILAlow; ≥12%: RILAhigh).