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 malignancies.& COPY; 2023 The Authors. Published by Elsevier Inc. on behalf of American Society for Radiation Oncology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study aimed to evaluate the oncologic and toxicity outcomes of using intensity modulated proton therapy (IMPT) for pelvic/abdominal reirradiation (re-RT) in patients with gynecologic cancers. The results demonstrated excellent local control and acceptable acute and late toxicity for re-RT with IMPT in gynecologic malignancies.