In this population-based study of 2,191 postmenopausal women with early stage breast cancer in 2003, 67% of women had received adjuvant hormonal therapy within one year of surgery. Women were more likely to receive hormonal therapy if they were better educated, had better informational/emotional support, and were younger. For those on hormonal therapy, women were more likely to be treated with an AI if they had insurance coverage for some or all medication costs, were wealthier, had better informational/emotional support, and were younger.
In December 2001, the initial results of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial were presented at the San Antonio Breast Cancer Symposium. At a median follow-up of 33 months, adjuvant anastrozole was superior to tamoxifen in terms of relapse-free survival.29
In January 2002, the NCCN endorsed anastrozole as “an alternative” to tamoxifen. However, it was not until 2005 that ASCO and St. Gallen each published guidelines recommending adjuvant AI use for postmenopausal women with hormone receptor-positive breast cancer and the FDA approved the adjuvant use of anastrozole.7, 8
In our study, 71% of women receiving adjuvant hormonal therapy were on an AI and over 80% of these women initiated AI use in 2003–2004. This finding confirms the results of previous studies demonstrating the substantial early adoption of AIs after the release of the initial ATAC results in December 2001, well prior to ASCO’s guideline publication in 2005.17, 19, 30
This rapid adoption of adjuvant AI use in the community is remarkable since, in the past, there has been a much slower adoption of other treatments (breast-conserving surgery) for breast cancer 31, 32
and to date, there is no overall survival advantage to using an AI, compared to tamoxifen.9
We found several independent predictors of adjuvant hormonal therapy use, including two SES factors: education and informational/emotional support (). The finding that better educated women (high school degree or higher) were more likely to receive any adjuvant hormonal therapy is not unexpected as discussions regarding the benefits and risks of hormonal therapy medications are extensive. Understanding and interpreting this information, believing the data supporting adjuvant hormonal therapy use, as well as weighing the pros and cons of these various medications may be more difficult for less educated women. Furthermore, women who have a more robust support system to seek advice and opinions may be better able to interpret and understand the benefits of hormonal therapy and be more comfortable deciding to take it. When a provider recommends adjuvant hormonal therapy, a woman may decide not to follow this advice for a variety of reasons; these two SES factors play a role in her decision. Interestingly, when adjusting for education and informational/emotional support, we found that race/ethnicity, income, insurance coverage for medication costs, and tangible social support were not associated with the receipt of hormonal therapy.
Our finding that relatively younger women (age 65–79 years) were more likely to receive adjuvant hormonal therapy is interesting since the indications for hormonal therapy are not age-related. Doctors and patients may be considering the possible risks/side effects associated with hormonal therapy (thromboembolic events, endometrial carcinoma, bone loss) more carefully in this older population. Our finding of geographic differences with hormonal therapy use is not surprising as there is much literature demonstrating the geographic variations in health care, and specifically, breast cancer care.32–36
Among women receiving hormonal therapy (), women were more likely to receive an AI if they had better informational/emotional support, had insurance coverage for medication costs, were wealthier (> $50,000 annual income), and were younger (age 65–69). Less AI use in relatively older women may be because both doctors and patients are particularly concerned with the possibility of additional bone loss associated with AI use and the potential morbidity of bony fractures in these older women. Women with more opportunities to discuss treatment decisions may ultimately come to value and believe in the benefits of an AI as opposed to tamoxifen more so than women with less informational/emotional support.
We found that wealthier women (>$50,000 annual income) and, most strikingly, women with any insurance coverage for medication costs were more likely to receive an AI as opposed to tamoxifen. This is not an unexpected finding given the markedly higher cost of AIs compared to tamoxifen. The fact that the lack of insurance coverage for medication costs was an important factor regarding type of hormonal therapy (AI versus tamoxifen) received has health care policy implications. Postmenopausal women with hormone receptor-positive breast cancer with no insurance coverage for medication costs may not be receiving an AI because of the financial burden associated with these medications.37
The most recent ATAC data, at a median of 100 months of follow-up, continues to clearly show long-term efficacy of anastrozole compared with tamoxifen.9
For more postmenopausal women with hormone receptor-positive breast cancer to derive benefit from adjuvant AI therapy, the review and possible revision of Medicare Part D and other insurance policies regarding AI coverage should be considered.
There are inherent limitations/biases with a survey study. In addition, our cohort is largely non-Hispanic white, due in part to the underlying racial distribution of the Medicare population in these four states as well as the predilection of breast cancer for Caucasian women; therefore, racial/ethnicity differences with hormonal therapy use may not be evident in our study. Another limitation is that women with the lowest income status will often have Medicaid pharmaceutical coverage. The fact that we found no association with income status and the initiation of hormonal therapy may be explained by this relationship. We also did not control for other non-Medicare insurance coverage.
We did not have hormone receptor status information from the state tumor registries in the majority of women. However, we can presume that approximately 75% of these postmenopausal women have hormone receptor-positive breast cancer.2, 3
Therefore, a relatively small proportion of women who might have been eligible for hormonal therapy did not receive it. This finding is encouraging as previous population-based studies have shown that only 50%-78% of older women with estrogen receptor-positive breast cancer received adjuvant tamoxifen therapy.38–41
Finally, our study is limited to women 65 years of age and older and therefore our findings may not be generalizable to younger postmenopausal women. However, performing this survey study in Medicare patients allowed for the analysis of several demographic and SES factors associated with hormonal therapy use in a large population-based cohort. To our knowledge, no other study addressing these particular issues has been performed. Two studies have found no differences in tamoxifen use between women of diverse education levels and SES backgrounds;15, 16
however, these studies were performed in countries (United Kingdom and Sweden) that have national health insurance coverage, unlike in the United States. Furthermore, no studies have examined potential differences in AI therapy use.
In summary, our results show that SES-related differences in hormonal therapy use exist and raise the possibility that SES-related survival disparities could be partially due to differences in hormonal therapy use. In this population-based cohort of older breast cancer survivors, almost all women eligible for hormonal therapy received it and the adoption of adjuvant AI therapy was early. Better-educated women (high school degree or higher) and women with better informational/emotional support were more likely to receive hormonal therapy, especially an AI. When counseling women about hormonal therapy, providers should be aware that these two factors play a role in a woman’s decision to take hormonal therapy. Surprisingly, other SES factors (race/ethnicity, income status, and insurance coverage for medication costs) did not affect hormonal therapy use in this cohort. However, for women on hormonal therapy, those with no insurance coverage for medication costs were significantly less likely to receive an AI than women who had at least some medication coverage. Given this finding, the continued high cost of AIs and the clear benefits of adjuvant AI use in postmenopausal women with hormone receptor-positive breast cancer, we recommend that policy-makers address this issue.