Neoadjuvant chemoradiation does not improve outcomes for patients undergoing resection for upper rectal cancer: A US Rectal Cancer Consortium analysis.

143 Background: The use of neoadjuvant chemoradiation (NCRT) for upper rectal cancer remains controversial. Our aim was to determine whether NCRT was associated with improved outcomes. Methods: The US Rectal Cancer Consortium was queried for patients who underwent resection of non-metastatic upper rectal cancer (≥12cm from anal verge) from 2007-2017. Primary outcomes were recurrence-free (RFS) and overall survival (OS). Secondary outcomes were postoperative complications. Results: 193 pts met inclusion criteria; 100 (52%) did not receive NCRT and 93 (48%) did. Median age was similar between groups (non-NCRT: 62 yrs; NCRT: 57 yrs; p=0.71). Patients in each group had similar gender and pathological stage (non-NCRT: 22% stage I, 32% stage II, 36% stage III; NCRT: 21% stage I, 23% stage II, 33% stage III; p=0.143). Median follow-up was 31 months (non-NCRT) and 34 months (NCRT). On Kaplan-Meier analysis, NCRT was not associated with improved RFS compared to non-NCRT (3-year RFS 85% vs. 80%; p=0.34) or OS (3-year OS 88% vs. 90%; p=0.49). This finding persisted on multivariable cox regression. R0 resection rate was similar between groups at 99% (non-NCRT) and 97% (NCRT; p=0.27). Anastomotic leak occurred in 11% of both cohorts. Creation of a diverting loop ileostomy (DLI) was nearly 3 times higher in NCRT (82%) versus non-NCRT patients (29%; p<0.001). Conclusions: Among patients with non-metastatic upper rectal cancer, NCRT did not improve survival or recurrence rates, but was associated with a nearly threefold higher DLI rate. Although NCRT is a mainstay of treatment for lower rectal cancer, our results do not support its use in upper rectal cancer. [Table: see text]