The current United States practice trend for neoadjuvant radiation for rectal cancer is unknown. In this study, 28,193 patients within the National Cancer Database treated with neoadjuvant radiation were identified and analyzed. Although long-course neoadjuvant chemoradiation was strongly preferred over short-course radiation, no difference in outcomes was identified. 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.
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