Purpose: A prior analysis by the Southwest Oncology Group (SWOG) showed that women and African American patients were adequately represented on cancer clinical treatment trials but that older patients were substantially underrepresented. Twenty-five percent of patients > or = 65 years old were enrolled onto SWOG trials from 1993 to 1996, whereas 63% of all patients with cancer were > or = 65 years old. Recognition of this under-representation led to a change in Medicare policy in 2000 to include coverage of routine patient care costs of clinical trials. We conducted an updated analysis of accrual trends.

Methods: The proportions of enrollment onto SWOG treatment trials by sex, race/ethnicity, and age (> or = 65 years) were computed for the years 1997 to 2000; corresponding rates in the United States were derived from US Census and National Cancer Institute Surveillance, Epidemiology, and End results data. Additionally, method of payment data were analyzed over time (1993 to 2003) to assess whether patterns in method of payment changed with the new Year 2000 Medicare policy on clinical trials coverage.

Results: The results showed continued adequate representation by sex and race/ethnicity. Older patient accrual on SWOG trials increased significantly since 2000, with 31% of patients > or = 65 years old enrolled from 1997 to 2000 and 38% enrolled from 2001 to 2003 (v 25% from 1993 to 1996). The percentage of patients using Medicare plus supplemental insurance also increased beginning in 2000, whereas the percentage of patients using Medicare alone remained the same.

Conclusion: Method of payment analyses provided evidence that the Year 2000 Medicare policy change had a positive impact, but only for those patients with supplemental private coverage of coinsurance costs. Improvements in the Medicare payment structure could further increase older patient participation in clinical trials.