Colorectal cancer in the elderly and the influence of lead time bias: better survival does not equate with improved life expectancy

Aims Poorer outcomes in those aged >= 80 years who undergo colorectal cancer surgery have been previously reported. Little is known about the natural history of those managed non-operatively. We explored outcomes in all patients with colorectal cancer aged >= 80 years at time of diagnosis based on treatment received. Methods Patients >= 80 years diagnosed with colorectal cancer in one hospital trust between 1998 and 2011 were identified from a prospectively maintained database. Primary endpoints were age at diagnosis, age at death/censor and mortality at 30, 90 and 365 days. Results Six hundred sixty-eight patients were identified. Four hundred twelve (61.7 %) underwent surgery, 44 (6.6 %) received endoscopic therapy and 212 (31.7 %) had no active treatment. Of those who underwent surgery, 359 (87.1 %) had resectional surgery, 34 (8.3 %) defunctioning only, 13 (3.2 %) received bypass surgery and 6 (1.5 %) had an open and close laparotomy. The mean age at diagnosis was younger in those who underwent surgical resection (83.7 years) compared to those having defunctioning surgery (84.9 years, P=0.043), endoscopic therapy (85.1 years, P=0.008) or no surgical intervention (85.6 years, P<0.001). There was no significant difference in the mean age of death or censor between groups. Conclusions There was no significant difference in age at death or censor between treatment groups among patients aged >= 80 years presenting with colorectal cancer, suggesting that differences in the observed survival time are heavily influenced by lead time bias. Age at death or censor should be reported in addition to survival times in this age group to enable fair comparison of outcomes.