Long-term Clinical Outcomes of Nonoperative Management With Chemoradiotherapy for Locally Advanced Rectal Cancer in the Veterans Health Administration

Abstract

Standard therapy for locally advanced rectal cancer includes neoadjuvant chemoradiation and surgery. Complete response (CR) rates after chemoradiation can be as high as 29%, suggesting that nonoperative management (NOM) may be reasonable with appropriately selected patients. We sought to identify potential NOM candidates. Using the Veterans Administration Central Cancer Registry, patients with stage II to III rectal cancer receiving chemoradiation with or without subsequent surgery were identified. Clinical CR (cCR) was assessed by physical examination, endoscopy, or imaging. Kaplan-Meier and log-rank tests were used to assess survival; multivariate analysis was performed using Cox proportional hazards. A total of 1313 patients were identified. Of these, 313 received chemoradiation alone (CRT cohort); 1000 received chemoradiation followed by surgery (CRT+S cohort). Median follow-up was 67.2months. Median overall survival (OS) was 68.5months. Median OS was 30.6months for CRT and 89.3months for CRT+S (P<.001). Median disease-specific survival (DSS) was 44.8months for CRT and not reached (NR) for CRT+S (P<.001). Sixty-five CRT patients (20.8%) had a cCR. Median OS for CRT cCR patients was 73.5months (P=.128 vs CRT+S); median DSS was NR (P=.161 vs CRT+S). One hundred thirty-seven (10.5%) CRT+S patients had a pathologic CR (pCR). Median OS with pCR was 133.7months (P<.001 vs CRT cCR), and median DSS was NR (P=.276 vs CRT cCR). CRT patients with cCR had similar OS and DSS versus CRT+S patients and similar DSS versus CRT+S patients with a pCR. This suggests that patients with locally advanced rectal cancer with a cCR to CRT have an excellent prognosis and may be candidates for organ preservation.