of the cost-effectiveness of increasing breast cancer screening and effective follow-up among African American women, the effects of tobacco taxation on tobacco use, the cost effectiveness of alternative strategies of managing Pap smear results, patterns of care for breast cancer in [health maintenance organization] HMO and fee-for-service settings, and the application of econometric techniques to cost and outcomes studies using Medicare data" (National Cancer Institute, 1998b, p. 34). NCI has collaborated with other federal agencies, including the Agency for Health Care Policy and Research, HCFA, and the National Institute on Aging, in sponsoring this research. Finally, DCP recently released a request for applications (RFAs) to assess ways of improving cancer diagnosis and treatment in rural areas. The aim of the RFA is to "strengthen the application of state-of-the-art cancer diagnosis and management practices in rural areas by enhancing links between rural health care providers and regional cancer specialists" (National Cancer Institute, 1998b, p. 34).

NCI intramural staff are investigating a range of possible and confirmed etiologic factors, including genetic susceptibility, environmental carcinogens, diet, behavior and lifestyle, and other risk factors, and their relationship with race and ethnicity in conferring a risk for cancer. For example, NCI scientists examined the relationship of rare variable nucleotide tandem repeat alleles of Ha-ras-1 in African Americans and whites as a possible predisposing factor in lung cancer and determined that differences in lung cancer rates between the two groups were due to differences in smoking patterns and not polymorphic gene variance.

Other studies on cancer etiology are summarized below by cancer site.

NCI scientists are studying the relationship between a variety of genetic, biochemical, behavioral, and environmental factors and prostate cancer in two large case-control investigations of African-American and white men in the United States and a sample of men in China at low risk for the disease. In that study vasectomy at a young age and family history are among the risk factors associated with prostate cancer, whereas researchers continue to examine the role of androgen metabolism and other biochemical markers in prostate cancer, DCEG and DCP staff are also studying these relationships in the NCI-sponsored Prostate, Lung, Colon, and Ovarian (PLCO) Cancer Screening Trial. These research efforts have been classified as Category I and II studies.

DCEG supports a wide range of Category I and II research aimed at understanding the causes of breast cancer and whether etiology