Clinical Outcomes of Intensity Modulated Proton Therapy Reirradiation for Gynecologic Malignancies.

Purpose: Pelvic reirradiation (re-RT) for patients with gynecologic cancers remains a challenge because of toxicity concerns. Given the dosimetric advantages of proton therapy, we aimed to assess oncologic and toxicity outcomes of patients with re-RT to the pelvis/abdomen with intensity modulated proton therapy (IMPT) for gynecologic cancers. Methods and Materials: We performed a retrospective analysis of all patients with gynecologic cancer treated at a single institution between 2015 and 2021 with IMPT re-RT. Patients were included for analysis if the IMPT plan had at least partial overlap with the treated volume of a previous radiation treatment. Results: A total of 29 patients were included for analysis, with 30 total courses of re-RT. The majority of patients had been treated previously with conventional fractionation to a median dose of 49.2 Gy (30-61.6 Gy). With a median follow-up of 23 months, 1-year local control was 83.5% and overall survival was 65.7%. Three patients (10%) developed acute and late grade 3 toxicity. One-year freedom from late grade 3+ toxicity was 96.3%. Conclusions: This is the first complete analysis of clinical outcomes for re-RT with IMPT for gynecologic malignancies. We demonstrate excellent local control and acceptable acute and late toxicity. IMPT should strongly be considered for treatments requiring re-RT for gynecologic malignancies.

Gross tumor volume margin and local control in p16-positive oropharynx cancer patients treated with intensity modulated proton therapy.

BACKGROUND: To determine if the extent of high-dose gross tumor volume (GTV) to clinical target volume (CTV) expansion is associated with local control in patients with p16-positive oropharynx cancer (p16+ OPC) treated with definitive intensity modulated proton therapy (IMPT). METHODS: We performed a retrospective analysis of patients with p16+ OPC treated with IMPT at a single institution between 2016 and 2021. Patients with a pre-treatment PET-CT and restaging PET-CT within 4 months following completion of IMPT were analyzed. RESULTS: Sixty patients were included for analysis with a median follow-up of 17 months. The median GTV to CTV expansion was 5 mm (IQR: 2 mm). Thirty-three percent of patients (20 of 60) did not have a GTV to CTV expansion. There was one local failure within the expansion group (3%). CONCLUSION: Excellent local control was achieved using IMPT for p16+ OPC independent of GTV expansion. IMPT with minimal target expansions represent a potential harm-minimization technique for p16-positive oropharynx cancer.

Amifostine- and chemoradiotherapy-related esophagitis in small cell lung cancer: a single institutional series and literature update.

OBJECTIVES: Concurrent chemoradiotherapy is considered a standard option for patients with stage 3 small cell lung carcinoma. A 25% risk of acute esophagitis is experienced by patients as a result of the volume of esophagus encompassed within a conformal radiotherapy technique. We reviewed our institutional experience administering the radioprotectant amifostine prior to daily radiotherapy to determine its effects on the onset of esophagitis. MATERIALS AND METHODS: From 2005 to 2016, 49 patients diagnosed with stage 3 small cell lung carcinoma received concurrent chemoradiotherapy. Chemotherapy (CT) consisted of cisplatin and etoposide with radiotherapy (RT) encompassing CT-identified gross tumor volume. In 32 patients (group 1), amifostine was delivered (500 mg subcutaneously divided in two injections) prior to the second daily RT fraction. The remaining 17 patients (group 2) did not receive amifostine due to choice or drug intolerance. RESULTS: Metrics of esophagitis included weight loss and opiate requirement during treatment. About 31% of group 1 required opiates at a median RT dose of 3300 cGy, and 41% of group 2 required opiates at a median dose of 2250 cGy. The dose of radiotherapy delivered to 50% of the esophageal volume for group 1 was significantly greater than that in group 2 (3000 cGy vs 576 cGy). CONCLUSION: In this modern retrospective series of thoracic chemoradiotherapy in the treatment of stage 3 small cell lung cancer, amifostine that was delivered subcutaneously postponed the onset of esophagitis.