Adoption of preoperative radiation therapy for rectal cancer from 2000 to 2006: a Surveillance, Epidemiology, and End Results Patterns-of-Care Study

Abstract

Purpose: The German rectal study determined that preoperative radiation therapy (RT) as a component of combined-modality therapy decreased local tumor recurrence, increased sphincter preservation, and decreased treatment toxicity compared with postoperative RT for rectal cancer. We evaluated the use of preoperative RT after the presentation of the landmark German rectal study results and examined the impact of tumor and sociodemographic factors on receiving preoperative RT.

Methods and materials: In total, 20,982 patients who underwent surgical resection for T3-T4 and/or node-positive rectal adenocarcinoma diagnosed from 2000 through 2006 were identified from the Surveillance, Epidemiology, and End Results tumor registries. We analyzed trends in preoperative RT use before and after publication of the findings from the German rectal study. We also performed multivariate logistic regression to identify factors associated with receiving preoperative RT.

Results: Among those treated with RT, the proportion of patients treated with preoperative RT increased from 33.3% in 2000 to 63.8% in 2006. After adjustment for age; gender; race/ethnicity; marital status; Surveillance, Epidemiology, and End Results registry; county-level education; T stage; N stage; tumor size; and tumor grade, there was a significant association between later year of diagnosis and an increase in preoperative RT use (adjusted odds ratio, 1.26/y increase; 95% confidence interval, 1.23-1.29). When we compared the years before and after publication of the German rectal study (2000-2003 vs. 2004-2006), patients were more likely to receive preoperative RT than postoperative RT in 2004-2006 (adjusted odds ratio, 2.35; 95% confidence interval, 2.13-2.59). On multivariate analysis, patients who were older, who were female, and who resided in counties with lower educational levels had significantly decreased odds of receiving preoperative RT.

Conclusions: After the publication of the landmark German rectal study, there was widespread, rapid adoption of preoperative RT for locally advanced rectal cancer. However, preoperative RT may be underused in certain sociodemographic groups.