Background: Substantial variability in the use of colon surveillance among colorectal cancer survivors has been reported. This study sought to examine trends in the use of colon surveillance among patients who have had colorectal cancer and to investigate factors associated with utilization.
Methods: Health maintenance organization enrollees with a diagnosis of local or regional colon or rectal cancer between January 1993 and December 1999 were studied. Receipt of a colon examination by colonoscopy or by flexible sigmoidoscopy, together with barium contrast radiography of the colon was determined from automated clinical records, and rates of colon surveillance were estimated by using survival analysis.
Results: A total of 1002 patients with a diagnosis of colorectal cancer met inclusion criteria for the study. Colon examinations were performed in 61% of patients within 18 months of diagnosis and in 80% of patients within 5 years of diagnosis. The median time from diagnosis to first colon surveillance examination (14 months) was unchanged over the study period, but the interval between first and second surveillance examinations increased by 17 months (p<0.001). Patients over 80 years of age (relative risk=0.32; 95% CI[0.22, 0.45]) and those with rectal cancer (relative risk=0.80; 95% CI[0.66, 0.97]) were less likely to undergo surveillance. Higher socioeconomic status (relative risk=1.29; 95% CI[1.03, 1.61]) and being married (relative risk=1.27; 95% CI[1.05, 1.53]) were associated with greater utilization. There was lower utilization among African American patients (relative risk=0.70; p=0.14) and increased utilization among other minorities (relative risk=1.47; p=0.06).
Conclusions: There is substantial variability in the use of colon examination for surveillance in patients with a history of colorectal cancer, and clinical and sociodemographic factors appear to influence the likelihood of surveillance.