Deprivation and Colorectal Cancer Surgery: Longer-Term Survival Inequalities are Due to Differential Postoperative Mortality Between Socioeconomic Groups

Deprivation is associated with poorer survival after surgery for colorectal cancer, but determinants of this socioeconomic inequality are poorly understood. A total of 4,296 patients undergoing surgery for colorectal cancer in 16 hospitals in the West of Scotland between 2001 and 2004 were identified from a prospectively maintained regional audit database. Postoperative mortality (< 30 days) and 5-year relative survival by socioeconomic circumstances, measured by the area-based Scottish Index of Multiple Deprivation 2006, were examined. There was no difference in age, gender, or tumor characteristics between socioeconomic groups. Compared with the most affluent group, patients from the most deprived group were more likely to present as an emergency (23.5 vs 19.5 %; p = .033), undergo palliative surgery (20.0 vs 14.5 %; p < .001), have higher levels of comorbidity (p = .03), have < 12 lymph nodes examined (56.7 vs 53.1 %; p = .016) but were more likely to receive surgery under the care of a specialist surgeon (76.3 vs 72.0 %; p = .001). In multivariate analysis, deprivation was independently associated with increased postoperative mortality [adjusted odds ratio 2.26 (95 % CI, 1.45-3.53; p < .001)], and poorer 5-year relative survival [adjusted relative excess risk (RER) 1.25 (95 % CI, 1.03-1.51; p = .024)] but not after exclusion of postoperative deaths [adjusted RER 1.08 (95 %, CI .87-1.34; p = .472)]. The observed socioeconomic gradient in long-term survival after surgery for colorectal cancer was due to higher early postoperative mortality among more deprived groups.