Short-course Versus Long-course Neoadjuvant Therapy for Non-metastatic Rectal Cancer: Patterns of Care and Outcomes From the National Cancer Database.

INTRODUCTION: The purpose of this study was to compare the utilization, pathologic response, and overall survival (OS) between long-course neoadjuvant chemoradiation (LC-CRT) and short-course neoadjuvant radiation (SC-RT) in the treatment of non-metastatic rectal cancer.

METHODS AND MATERIALS: Retrospective data was obtained from the National Cancer Database (NCDB) for patients diagnosed with clinical stage II or III (limited to T3, any N or T1-2, N1-2) rectal cancer between 2004 and 2014 (28,193 patients). Univariate and multivariate analyses were performed to investigate factors associated with receipt of SC-RT, pathologic complete response (pCR) rate, and OS. Patients were compared based on the neoadjuvant therapy they received prior to tumor resection. SC-RT was defined as 25 Gy given over 1 week prior to surgery (with or without chemotherapy as part of their treatment course). LC-CRT was defined as 45 to 60 Gy given over 5 to 6 weeks (with chemotherapy) prior to surgery.

RESULTS: A total of 27,988 (99%) of patients received LC-CRT, and 205 (1%) patients received SC-RT. Receipt of SC-RT was associated with older age, more comorbidities, and treatment at an academic facility (P < .001 for each). Additional days from radiation completion to surgery was associated with a higher pCR rate (P < .001 for both). LC-CRT did not lead to increased OS compared with SC-RT (P = .517).

CONCLUSIONS: In this United States database study, there was no improvement in OS for patients receiving LC-CRT compared with SC-RT; however, a longer interval between radiation therapy and surgery led to a higher pCR rate. Academic facilities were more likely to utilize SC-RT compared with other facilities.