diagnoses is also dependent on the quality of the overall population data from the U.S. Bureau of the Census (i.e., the "denominator"), which are less reliable for some populations (especially many ethnic minority groups) within SEER program coverage areas. Finally, for many rare cancers and for cancers among smaller ethnic groups, incidence data are unreliable, therefore limiting the kinds of analyses that can be performed (Tejeda et al., 1996). Only a few published studies account for these limitations, and these are cited below. The committee therefore interprets the proportionality of ethnic minority participation in clinical trials with caution.
Sufficient data are not available from NCI to evaluate clinical trial accrual for medically underserved populations.
Of the 13 cooperative groups funded in 1997, 4 are focused on pediatric cancers (the Children's Cancer Group [CCG], the National Wilms' Tumor Study [NWTS], the Intergroup Rhabdomyosarcoma Study Group [IRS], and the Pediatric Oncology Group [POG]), 5 are focused on specific cancers (the Brain Tumor Cancer Group, the Gynecologic Oncology Group [GOG], IRS, the National Surgical Adjuvant Breast and Bowel Project [NSABP], and NWTS), and 2 are small or regional groups (the M.D. Anderson Cancer Center [MDA] and the North Central Cancer Treatment Group [NCCTG]). These groups all face special circumstances that may affect the accrual of minorities in clinical trials. The groups focused on pediatric cancers, for example, enroll the majority of pediatric cancer patients in the United States (approximately 70 percent), making proportionate accrual of minority patients more likely (Bleyer, 1977; Tejeda et al., 1996). The remainder, however, are large nonspecialty trial groups that recruit subjects from broad adult patient populations.
NCI Clinical Trials Cooperative Group statistics indicate that the overall level of participation of U.S. cancer patients in Clinical Trials Cooperative Group is about 2.5 percent. In an examination of accrual patterns by ethnicity and age for all cooperative group trials during the period between January 1991 and June 1994, Tejeda et al., (1996) found that overall, ethnic minority representation is proportional in comparison to the incidence of cancer among ethnic minorities in the U.S. population. Specifically, the level of enrollment of African Americans was found to be 9.6 percent, that of Hispanics was 5.6 percent, and that of whites was 84.8 percent. These figures are very close to the estimated proportions of individuals with cancer in these groups in the United States (9.4 percent among African Americans, 3.4 percent among Hispanics, and 87.2 percent among whites).