was substantial variation in the use of radiation therapy depending on the patient's type of insurance: 45 percent of Medicaid beneficiaries received radiation therapy, compared with 78 percent of Blue Cross/Blue Shield subscribers and 88 percent of Medicare enrollees.
An earlier study by Johnson et al. (1994), which looked only at the use of adjuvant therapy in women with Stage I and II breast cancer diagnosed in 1983-1989, also found high adherence to National Cancer Institute Consensus Conference guidelines among community hospitals participating in the Community Clinical Oncology Program (CCOP). The CCOP was initiated by the NCI in 1983 to increase community participation in clinical research (Kaluzny et al., 1995). In this study, the proportion of women with node-positive breast cancer receiving adjuvant hormone or chemotherapy was highest in 1988 after NCI released a clinical alert advising physicians of the potential benefits in women with node-negative disease. The proportion of women with node-negative breast cancer treated with adjuvant therapy increased from 26 percent in the quarter before the clinical alert to 54 percent in the quarter following its release. During the same period, the proportion of women with node-positive breast cancer treated with adjuvant therapy increased from 81 to 90 percent. A year after the NCI clinical alert, the percentage of node-negative patients treated remained elevated above baseline at 46 percent, while the percentage of node-positive women treated with adjuvant therapy had fallen back to the baseline rate of 79 percent. It is not known if the clinical alert had a transient spillover effect on the treatment of node-positive disease. The proportion of women receiving adjuvant therapy in this study approaches a level one would expect if all women who could benefit from adjuvant therapy were being offered treatment. These data are limited in their generalizability, however, because the facilities that chose to participate in the NCI's CCOP are more likely to have an interest in cancer treatment and more likely to adhere to NCI guidelines than the average facility in the community. Notwithstanding, these data—and those reported by Hillner et al. (1997) and Guadagnoli et al. (1998a)—demonstrate high levels of adherence to treatment standards for adjuvant therapy in breast cancer in selected patient populations, with the notable exception of the low use of hormone therapy in postmenopausal patients.
The higher rates of radiation therapy reported by Hillner et al. (1997), Guadagnoli et al. (1998a), and Young et al. (1996) compared with the earlier study of Farrow et al. (1992), may reflect a general improvement in the quality of breast cancer care in the United States. However, given the selected patient populations in the Hillner et al. (1997), Guadagnoli et al. (1998a), and Young et al. (1996) studies, these data must be interpreted cautiously, especially when attempting to generalize from these results to the entire U.S. population. The Hillner et al. (1997) study includes only women younger than 65 with private fee-for-service health insurance. Also, although the Guadagnoli et al. (1998a) study is not limited to a privately insured population, it is limited to patients treated at hospitals that agreed to participate and therefore may be providing a higher standard of care. The Young et al. (1996) study compared women with Blue Cross/Blue Shield, Medicare, and Medicaid and found that women with Medicaid received much poorer quality care. Nevertheless, these studies suggest that at least some women in the United States had access to high-quality breast cancer care by 1995. However, even among these women there is cause for concern since only 60 percent of postmenopausal women with node-positive, estrogen receptor-positive cancers received adjuvant hormone therapy.
One study conducted in 1988-1989 suggests that the dose of adjuvant therapy for women with breast cancer is inappropriately low. Schleifer et al. (1991) audited the care of 107 women with breast cancer by 29 oncologists at three university-affiliated practices. Adjuvant therapy over six months was retrospectively reviewed and patients were prospectively interviewed. More than