Patterns of care for adjuvant therapy in a random population-based sample of patients diagnosed with colorectal cancer.

OBJECTIVES: Over the past decade, clinical trials have proved the efficacy of treatments for colorectal cancer (CRC). This study tracks dissemination of these treatments for patients diagnosed with stage II and III disease and compares risk of death for those who received guideline therapy to those who did not.
METHODS: We conducted a stratified randomly sampled, population-based study of CRC treatment trends in the United States. Multivariate models were used to explore patient characteristics associated with receipt of treatments. We pooled data with a previous study-patients diagnosed in 1987-1991 and 1995. Cox proportional hazards models were used to assess observed cause-specific and all-cause mortality.
RESULTS: In 2000, guideline therapy receipt decreased among stage III rectal cancer patients, but increased for stage III colon and stage II rectal cancer patients. As age increased, likelihood of receiving guideline treatment decreased (p < 0.0001). Overall, race/ethnicity was significantly associated with guideline therapy (p = 0.04). Rectal patients were less likely to have received guideline treatment. Consistent with randomized clinical trial findings, all-cause mortality was lower in patients who received guideline therapy, regardless of Charlson comorbidity score.
CONCLUSIONS: Mortality was decreased in patients receiving guideline therapy. Although, rates of guideline-concordant therapy are low in community clinical practice, they are apparently increasing. Newer treatment (oxaliplatin, capecitabine) started to disseminate in 2000. Racial disparities, present in 1995, were not detected in 2000. Age disparities remain despite no evidence of greater chemotherapy-induced toxicity in the elderly. More equitable receipt of cancer treatment to all segments of the community will help to reduce mortality.