Clinical and pathological outcomes of induction chemotherapy before neoadjuvant radiotherapy in locally-advanced rectal cancer

Background and Objectives In North America, preoperative combination chemoradiation is the most commonly recommended and utilized approach to locally advanced rectal cancer. There is increasing interest in the use of induction chemotherapy (IC) before radiation and surgery in locally advanced rectal cancer. How widely IC is being used and whether it improves pathologic and oncologic outcomes is unknown. Methods We evaluated clinical stage 2 or 3 rectal cancer patients in the National Cancer Database between 2006 and 2015. We identified predictors of use of IC with multivariable logistic regression and compared survival between groups using Cox proportional hazards regression. Results Among 36 268 patients, IC use increased significantly over time from 5.5% in 2006 to 15.9% in 2015 (P < 0.001). Treatment at a hospital with a high IC rate was an independent predictor of receipt of IC. IC and traditional therapy yielded similar pathologic complete response rates (32.2% vs 30.5%, P = 0.2) and similar 5-year survival (82.4% vs 81.4%, 0.71). Conclusions Use of IC for locally advanced rectal cancer has increased significantly. The choice of IC seems to be driven more by institutional and regional practice patterns than clinical characteristics and is not associated with improved pathologic or oncologic outcomes.