Discrepancy between Consensus Recommendations and Actual Community Use of Adjuvant Chemotherapy in Women with Breast Cancer

Although the efficacy of chemotherapy in prolonging survival for women with breast cancer has been well documented (1–12), limited population-based information is available on the actual use of chemotherapy. Some hospital-based surveys of breast cancer have examined the use of chemotherapy (13–15), but the completeness of information has been questioned because chemotherapy is frequently administered in outpatient settings. The evolution of recommendations about the use of adjuvant chemotherapy in women with early breast cancer is illustrated by the National Institutes of Health (NIH) consensus development conferences (1, 3, 12). In 1985, the consensus conference recommended chemotherapy for premenopausal women with lymph node–positive cancer (1). By 1990, the consensus conference recommended chemotherapy for both premenopausal and postmenopausal women with lymph node–positive cancer and for women with cancer confined to the breast but with poor prognostic features, such as large size or negative hormone receptor status (3). The 2000 consensus conference extended the recommendation of chemotherapy to premenopausal and postmenopausal women with node-positive tumors or with node-negative tumors greater than 1 cm in size, regardless of hormone receptor status (12). Because limited information is available from clinical trials of chemotherapy in women 70 years of age and older, none of the consensus conferences made specific recommendations for that age group, other than to invoke individual decisions based on clinical circumstances and patient preferences. We recently reported on chemotherapy use in women age 65 years and older by using the Surveillance, Epidemiology, and End Results (SEER) tumor registry data linked to Medicare data (16, 17). As expected, chemotherapy use sharply decreased in women older than 70 years of age, and women with higher-stage, larger, or estrogen receptor–negative tumors were more likely to receive chemotherapy (16, 17). We review the use of chemotherapy in women residing in New Mexico who were 20 years of age or older and received a diagnosis of breast cancer between 1991 and 1997. We hypothesized that chemotherapy use would not vary by age in women younger than 65 years of age who have tumor characteristics for which chemotherapy is generally recommended. Furthermore, we hypothesized that use of chemotherapy would vary by age with highest use in younger women (<45 years of age) among women who had tumors with characteristics for which no clear consensus recommendations had been made.