Is Inflammatory Bowel Disease a Contraindication for Pelvic XRT in Patients With Gynecologic Cancers? Efficacy and Toxicity Outcomes in the Modern Era.

PURPOSE/OBJECTIVE(S) Pelvic radiation therapy (XRT) is an integral part of treatment for many patients with gynecologic malignancies to help decrease the risk of morbid recurrences and allow for organ preservation as an alternative to radical surgery. Historically, providers have been reluctant to offer pelvic XRT to inflammatory bowel disease (IBD) patients due to concerns over increased acute and late toxicities of treatment based on limited historical data, precluding many patients from receiving optimal therapy. This retrospective study investigated the use of pelvic XRT in patients with gynecologic cancers and IBD treated in the modern era to assess toxicity and efficacy. MATERIALS/METHODS Patients with IBD and a gynecologic malignancy receiving pelvic XRT or chemo-XRT between January 2014 and June 2020 were included. Data abstracted included diagnosis, stage, XRT technique/dose, use of concurrent chemotherapy, and acute and late CTCAE v4.0 toxicity scores. Statistics were performed using statistical software. RESULTS Six patients with IBD and FIGO stage I-III or recurrent cancer of the gynecological tract who received definitive or adjuvant XRT to the pelvis were identified. Median follow-up was 29 months (range 6-66 months). Four patients (66%) had Crohn's Disease and two (33%) had ulcerative colitis. Primary disease locations were uterus (2), vulva (1), vagina (2), and cervix (1). Four patients received concurrent platinum-based chemotherapy with pelvic XRT. Pelvic XRT was delivered using IMRT/VMAT in all patients with doses of 45-57.6 Gy in 25-32 fractions. 100% of patients completed treatment without treatment breaks. No patients received treatment for active IBD during XRT, but most (83%) were on loperamide at baseline. No patients experienced any acute 3 or greater toxicity; most common toxicities reported during treatment were grade 1-2 fatigue (100%), grade 1 diarrhea (50%), grade 1 nausea (66%), and grade 1-2 dermatitis (66%). One patient experienced grade 2 rectal proctitis 5 years out from treatment; no other patients experienced late GI toxicity at last recorded follow-up. Two patients (33%) developed distant disease within 6 months of completing XRT, one of whom died of disease. No patient developed locoregional recurrence and 66% of patients remain disease free at the time of last follow-up. 83% were able to avoid upfront radical surgery, including 3 patients who would have required total pelvic exenteration. CONCLUSION In our single-institution series, pelvic XRT +/-chemotherapy is well-tolerated in patients with gynecologic malignancies and IBD. The use of pelvic XRT in this population led to excellent loco-regional control outcomes that allowed patients to avoid radical upfront surgeries and preserve organ function. Our small series represents the largest cohort of IBD patients with gynecologic cancers treated with pelvic XRT or chemo-XRT and suggests that strong consideration should be given to offering pelvic XRT to IBD patients diagnosed with gynecologic cancers. AUTHOR DISCLOSURE S.R. Amarnath: None.