Preoperative chemoradiotherapy for rectal cancer and impact on outcomes - A population-based study.

Abstract

Preoperative (chemo)radiotherapy ((C)RT) for rectal cancer is, in Norway, restricted to patients with cT4-stage or threatened circumferential resection margin. This nationwide population-based study assessed the use of preoperative (C)RT in Norway and its impact on treatment outcomes. Data from The Norwegian Colorectal Cancer Registry were used to identify all stage I-III rectal cancers treated with major resection (1997-2011: n=9193). Cumulative risk of local recurrence, distant metastasis, and relative survival was estimated for patients in 2007-2011 (n=3179). Multivariate regression-models were used to compare outcomes following preoperative (C)RT and surgery versus surgery alone. The proportion of patients given preoperative (C)RT increased from 5% to 49% during 1997-2011. Preoperative (C)RT was associated with reduced risk of local recurrence (hazard ratio (HR)=0.55; 95% CI=0.29-1.04) and a tendency of improved survival (excess HR=0.75; 95% CI=0.52-1.08) with significant effects in patients aged ≥70years (local recurrence: HR=0.35; 95% CI=0.13-0.91; survival: excess HR=0.58; 95% CI=0.35-0.95). This study indicates that when use of preoperative (C)RT is restricted to selected high-risk rectal cancers, preoperative (C)RT is associated with improved local recurrence, and possibly improved survival, when studied on a population-based level.