Combined Modality Therapy for Rectal Cancer: Analysis of Potential Differences in Disease Presentation, Treatment Adherence, and Treatment Outcome According to Race

Abstract

Population-based studies suggest that African Americans (AAs) with rectal cancer have a worse overall outcome compared to whites. This relationship was explored in a cohort of locally advanced rectal cancer patients treated with preoperative chemoradiation (CRT) and surgery at two urban academic cancer centers. A total of 146 patients underwent curative-intent combined modality therapy for adenocarcinoma of the rectum. The median age was 57 years. Median dose was 50.4 Gy, given with 5-flourouracil based concurrent chemotherapy. Analysis was performed to test for differences in disease presentation, adherence to recommended therapy, and treatment outcome (freedom from failure, FFF) by race. Median follow-up was 34 months from completion of chemoRT. Twenty-six patients (18%) were AA, and 120 (82%) patients were White, Asian, or Hispanic. AA patients had longer times from diagnosis to start of therapy (median 45 days vs. 35 days, p < 0.01) and from CRT completion to surgery (median 42 days vs. 46 days, p = 0.03). CRT treatment time was no different between the two groups (median 38 days for both groups, p = 0.53). In the subset of patients with preoperative staging by endoscopic ultrasound (EUS, n = 119), AA patients presented with more favorable disease (20% stage I, 47% stage II, 33% stage II) compared with non-AA patients (0% stage I, 50% stage II, 48% stage III, 2% stage IV, p < 0.01). Among patients with stage II-IV disease (n = 116), the rate of any T or N downstaging was lower for AA patients (58% vs. 79%, p = 0.13). Pathologic complete response rates were also lower (17% vs. 26% for non-AA patients, p = 0.47), although not statistically different. AA patients were less likely to receive adjuvant chemotherapy (58% vs. 89%, p = 0.01). Log-rank analysis showed that time from diagnosis to therapy, and time from CRT to surgery were not associated with any difference in FFF when stratified by the median value. Similarly, completion of adjuvant chemotherapy was not associated with FFF. Overall, AA patients were not more likely to recur after therapy (FFF-3y, 100% for AA patients vs. 81% for non-AA patients, p = 0.09). This analysis reflects differences in time from preoperative therapy to surgery and a lower rate of adjuvant therapy in AA patients with rectal cancer treated in at two urban academic cancer centers. These differences did not appear to result in inferior disease outcome for this cohort. Further study is necessary to explore the reasons underlying the delays in therapy and lower rates of adjuvant chemotherapy for AA patients.