Increase of chemotherapy use in older women with breast carcinoma from 1991 to 1996

Chemotherapy has been shown to be efficacious in women with breast carcinoma in numerous clinical trials over the past several decades.1–3 However, the efficacy of chemotherapy and guidelines for its use vary by tumor stage and patient age.4–10 In the 1985 National Institutes of Health (NIH) consensus statement, combination chemotherapy was considered as the standard of care for premenopausal women and postmenopausal women younger than 70 years with operable breast carcinoma with positive lymph nodes and for those with negative lymph nodes with high-grade tumor histology or negative hormone receptors.4 This recommendation was essentially repeated in the 1990 and 2000 consensus conferences, with the additional statement that lymph node negative tumors greater than 1 cm should be considered for adjuvant chemotherapy.5,8 These consensus recommendations noted the lack of evidence of efficacy of adjuvant chemotherapy in women age 70 years and older. Meta-analyses have shown decreasing benefit from adjuvant chemotherapy with increasing age, though few women age 70 years and older have been enrolled in such trials.1–3 Accordingly, there are no clear recommendations for adjuvant chemotherapy in women age 70 years and older. For women with more advanced tumor (Stages III and IV), systemic therapy (chemotherapy or hormonal therapy or both, depending on hormonal receptor levels) was recommended as primary therapy in both premenopausal and postmenopausal women.10 There is little information available on the actual use of chemotherapy and how closely this use mirrors consensus recommendations. The previous reports on the prevalence of chemotherapy use have produced conflicting results.11–21 A series of the national hospital-based surveys of breast carcinoma in the United States, organized by the American College of Surgeons,12,13 reported that 16.4% of women of all ages with local to distant breast carcinoma had used chemotherapy in 1976, and it increased to 22.7% in 1981. By 1991, 46.6% of women received chemotherapy or tamoxifen (no specific data given on the use of chemotherapy only).12 The prevalence of chemotherapy use in 17 community hospitals across the nation in 1982 in women age 65–74 years was 55% for regional stage and 49% for distant stage.11 In contrast, among women age 65 or older with early stage breast carcinoma diagnosed in a large health maintenance organization (HMO), only 13% of them received chemotherapy in 1993–1994.14 This study was conducted to assess temporal trends in the use of chemotherapy among women age 65 years and older who received a diagnosis of breast carcinoma from 1991 to 1996, using the SEER cancer registry cases linked with Medicare claims. We hypothesized that, given the relative stability of consensus conference recommendations on chemotherapy use during this period, the patterns of use would more closely approximate consensus recommendation over time. Because no clear recommendations exist for women age 70 and older, we expected to see a closer approximation to consensus conference recommendations among women age 65–69 years than in older women.