Gastrointestinal Cancer

MO 08 - GI 2 - Anorectal and Liver Cancers

1099 - Toxicity and Efficacy Outcomes of Preoperative Pelvic Radiation Therapy in Patients with Inflammatory Bowel Disease and Rectal Cancer

Monday, September 16
11:50 AM - 11:55 AM
Location: Room W175

Toxicity and Efficacy Outcomes of Preoperative Pelvic Radiation Therapy in Patients with Inflammatory Bowel Disease and Rectal Cancer
S. R. Amarnath; Cleveland Clinic Taussig Comprehensive Cancer Center, Cleveland, OH

Purpose/Objective(s): Preoperative pelvic radiation (XRT) or chemo-XRT therapy is considered standard of care treatment for stage II/III rectal cancer to decrease the risk of local recurrence. Although inflammatory bowel disease (IBD) is a risk factor for the development of rectal cancers and locally advanced cancers are frequently diagnosed in this population, the use of XRT is considered by many to be contraindicated. This retrospective study investigated the use of pelvic XRT in IBD patients in the modern era to assess toxicity and efficacy outcomes.

Materials/Methods: Patients with IBD and rectal cancer receiving preoperative radiation (25 Gy/5fx) or chemo-XRT (50-50.4 Gy/25-28fx) between January 2014 and December 2018 were included. Data was abstracted included diagnosis, stage, technique (3D or IMRT/VMAT), XRT dose, and acute and late CTCAE v4.0 toxicity scores. Statistics were performed using statistical software.

Results: Fifteen patients with IBD and AJCC stage II-IVA adenocarcinoma of the anorectum who underwent preoperative XRT were identified. Median follow-up was 17 months (range 4-33 months). Nine patients (60%) had Crohn’s Disease and six (40%) had ulcerative colitis. Twelve of 15 (80%) of patients received concurrent chemo-XRT with capecitabine or CI-5FU and 20% received short course XRT. 100% of patients completed treatment without treatment breaks. Thirty-three percent (5/15) of patients were on active IBD treatment during XRT, but no differences were seen in toxicity compared to those not on active therapy. Sixty-six percent of patients were treated using IMRT/VMAT due to the need for inguinal node coverage or anatomical considerations; all others received 3D-CRT with no differences in toxicity based on treatment technique. No patients experienced any acute grade 3 or greater toxicity and the most common toxicities were grade 1-2 fatigue (73%) and grade 1-2 diarrhea (40%). No patients experienced a late toxicity by last recorded follow-up. Ninety-three percent of patients underwent surgery (85% APR, 15% exenteration). Most patients had a pathologic response to therapy (tumor regression score: 0 (14%), 1 (21%), 2 (43%), 3 (7%), unknown (14%)). Six patients (40%) developed recurrences (3 distant only, 1 pelvic only, and 2 distant + pelvic) and four died of their disease in the follow-up period.

Conclusion: This is the largest series of patients with IBD and rectal cancer treated with preoperative XRT. With modern treatment techniques, pelvic XRT, with or without concurrent chemotherapy, is a safe and efficacious treatment for patients with IBD and locally advanced rectal cancer with a reasonable toxicity profile. Given the importance of preoperative XRT in decreasing pelvic recurrences in rectal cancer patients, strong consideration should be given to offering pelvic XRT standardly to patients with inflammatory bowel disease.

Author Disclosure: S.R. Amarnath: None.

Sudha Amarnath, MD

Cleveland Clinic Taussig Cancer Institute

Disclosure:
Employment
Cleveland Clinic Taussig Comprehensive Cancer Center

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