Age, Sex, and Racial Differences in the Use of Standard Adjuvant Therapy for Colorectal Cancer

Abstract

PURPOSE: Dissemination of efficacious adjuvant therapies for resectable colorectal cancer has not been comprehensively described. Trends, patterns, and outcomes of adjuvant therapy for colorectal cancer, focusing on age, sex, and racial/ethnic differences, are reported. MATERIALS AND METHODS: Population-based random samples of patients diagnosed with colorectal cancer diagnosed in nine geographic areas were collected annually between 1987 and 1991 and in 1995 (n = 4,706). Data were obtained from medical record reviews. Multiple logistic regression was used to assess the use of standard adjuvant chemotherapy for colon and rectal cancers. The Cox proportional hazards model was used to assess 9-year mortality. RESULTS: From 1987 until 1995, the use of adjuvant therapy increased in all age groups. There was an increase starting in 1989 for colon and in 1988 for rectal cancer. Use of standard therapy was 78% for those younger than 55 years and 24% for those older than 80 years. White patients received standard therapy more frequently than African-Americans (odds ratio, 1.75; 95% confidence interval [CI], 1.09 to 2.83). All-cause and cancer-specific mortality exceeding 9 years were lower in those who received standard therapy (all-cause risk ratio [RR], 0.73; 95% CI, 0.61 to 0.88; cancer-specific RR, 0.87; 95% CI, 0.70 to 1.09). CONCLUSION: Standard adjuvant therapies for colorectal cancer disseminated into community practices during the 1990s. However, evidence exists of differential use of therapies by older patients and by African-Americans. The use of standard therapies in the general population is associated with lower mortality. Improved dissemination of standard adjuvant therapies to all segments of the population could help reduce mortality.