RADIORYTHMIC: Phase III, Opened, Randomized Study of Postoperative Radiotherapy Versus Surveillance in Stage IIb/III of Masaoka Koga Thymoma after Complete Surgical Resection.

INTRODUCTION: Thymomas are rare intrathoracic malignancies that may be aggressive and difficult to treat. Knowledge and level of evidence for treatment strategies are mainly based on retrospective studies or expert opinion. Currently there is no strong evidence that postoperative radiotherapy after complete resection of localized thymoma is associated with survival benefit in patients. RADIORYTHMIC is a phase III, randomized trial aiming at comparing postoperative radiotherapy versus surveillance after complete resection of Masaoka-Koga stage IIb/III thymoma. Systematic central pathologic review will be performed before patient enrollment as per the RYTHMIC network pathway. PATIENTS AND METHODS: Three hundred fourteen patients will be included; randomization 1:1 will attribute either postoperative radiotherapy (50-54 Gy to the mediastinum using intensity-modulated radiation therapy or proton beam therapy) or surveillance. Stratification criteria include histologic grading (thymoma type A, AB, B1 vs B2, B3), stage, and delivery of preoperative chemotherapy. Patient recruitment will be mainly made through the French RYTHMIC network of 15 expert centers participating in a nationwide multidisciplinary tumor board. Follow-up will last 7 years. The primary endpoint is recurrence-free survival. Secondary objectives include overall survival, assessment of acute and late toxicities, and analysis of prognostic and predictive biomarkers. RESULTS: The first patient will be enrolled in January 2021, with results expected in 2028.

Imatimid-induced bone marrow necrosis detected on MRI examination and mimicking bone metastases.

Imatinib has revolutionized the treatment and prognosis of patients with gastrointestinal stromal tumors (GIST). In contrast to liver and/or abdominal involvement, bone metastases are an uncommon event in GIST. We report here two patients with metastatic GIST who developed pelvic bone marrow focal lesions visible on MRI examinations, while Imatinib dramatically improved other tumor sites. A biopsy in one patient diagnosed bone marrow necrosis. The other patient had a favorable follow-up over several years, without bone metastases. Focal bone marrow abnormalities, detected on MRI examinations and mimicking bone metastases in patients who were otherwise responding, should be considered as probable bone marrow necrosis.

Impact of surgery on advanced gastrointestinal stromal tumors (GIST) in the imatinib era.

BACKGROUND: The role for surgery in patients with "unresectable" gastrointestinal stromal tumors (GIST) treated with imatinib is still not defined. The objective of this retrospective study was to evaluate the feasibility and benefit of this secondary surgery. METHODS: Progression-free survival (PFS) in a group of patients who underwent secondary surgery was compared to that of patients treated exclusively with imatinib. RESULTS: Of 180 patients with unresectable GIST treated with Imatinib, 22 (12%) underwent secondary surgery, following which one patient achieved a complete radiological response, 19 achieved a partial response (PR), in one patient the disease was stable, and in one patient there was reactivation of local occlusive disease after an initial PR. No patient with overall progression was to undergo surgery. At the beginning of imatinib therapy, five patients with metastases underwent emergency surgery [hemorrhage (n = 3) due to rupture of large necrotic masses], which ultimately resulted in three of the five patients dying postoperatively. A macroscopically complete resection was achieved in all primary tumors (5/5) and in ten of the 17 metastases. Pathological analysis revealed two complete response (CR) and 17 PR, and no treatment effect was evidenced in three patients. Two-year overall survival after surgery was 62%. The median PFS calculated from the initiation of imatinib therapy was 18.7 months for all operated patients and 23.4 months after planned surgery. CONCLUSION: Primary tumors that become amenable to surgery with prior imatinib therapy, evolving necrosis and localized progression (to avoid life-threatening complications) could benefit from this secondary surgery. For the majority of other residual lesions, the potential benefit of secondary surgery should be evaluated in randomized studies in the future since PFS is similar to that reported among non-operated patients.