A study of women with estrogen receptor-positive, invasive breast cancer showed that while most women start and complete treatment with hormonal therapy as prescribed, certain groups are more likely than others to stop taking it before the recommended date, or to never take it at all.
Hormonal therapies are medicines like tamoxifen and aromatase inhibitors, which work either by blocking the effects of estrogen on cancer cells or by decreasing estrogen production. Both therapies can stop or slow the growth of estrogen receptor-positive (ER-positive) breast cancers.
Tamoxifen is standard of care for premenopausal women (those who still have their monthly period) who have ER-positive breast cancer. It is usually taken for 5 years after the completion of surgery, radiation therapy and chemotherapy. Postmenopausal women, those who have already started menopause and no longer have menstrual periods, are often offered a combination of tamoxifen and aromatase inhibitors to treat ER-positive cancer over the 5 years after other treatment ends.
Both tamoxifen and aromatase inhibitors have been shown to reduce the risk of cancer recurrence. Research has also shown that 10 years of tamoxifen may lower risk of recurrence and increase rates of survival when compared with 5 years of treatment. Despite this, some women choose not to take hormonal therapy at all, or choose to stop its use before the standard-of-care 5-year mark.
Researchers of this current analysis explored whether women who started taking hormonal therapies continued taking them as prescribed and what factors had an impact on their decision.
A total of 743 women with ER-positive breast cancer whose medical information was available in the Metropolitan Detroit and Los Angeles County Surveillance, Epidemiology and End Results (SEER) cancer registries completed surveys about their experience with taking hormonal therapy. The women were 20 – 79 years of age, had stage I – III invasive disease, and were diagnosed between 2005 and 2007. SEER collects information on age at diagnosis, race and ethnicity, cancer stage, tumor grade and size, and hormonal status.
The women completed an initial survey 9 months after their diagnosis, and a second survey 4 years after diagnosis.
At 4 years, they were asked
- if they had taken any hormonal therapy for breast cancer in the last week.
- if they had ever taken hormonal therapy for breast cancer.
- whether their follow-up care was managed by a medical or surgical oncologist
- if they felt they received enough information about hormonal therapy after they completed primary treatment.
- the number of medicines they took each week.
In addition, the women completed a separate survey to determine their level of worry about recurrence. Higher scores showed greater worry.
Based on the surveys, the researchers found that
- 663 women initiated therapy (85.2 percent of the total), of whom 551 (83.1 percent) persisted, or started and continued hormonal therapy as prescribed.
- Latina and African-American women were more likely to start treatment than Caucasian women.
- Women seen by a medical oncologist for follow-up care were more likely to start treatment than those seen by a surgical oncologist.
- Women who felt they did not receive enough information were less likely to begin treatment.
- Women with higher fear of recurrence scores had significantly higher rates of persistence.
- Older women were less likely to persist than younger women.
- Women who took two or more medicines per week were more likely to continue treatment as prescribed than women who took only one or no medicines per week.
- Women who never started treatment noted their decisions were based on worries about side effects, general dislike of medicines, and statements from their doctors that hormonal therapy wasn’t needed or was the woman’s choice.
What This Means for You
This research shows that despite the reported benefits of reduced risk of cancer recurrence and improved survival rates, some women may never start taking prescribed hormonal therapy or decide to stop treatment early.
If you are eligible for hormonal therapy after your primary treatment, talk with your doctor about the risks and benefits of following through with treatment. It’s OK to ask about side effects or to tell your doctor if you’re concerned about the long-term effects of taking a medicine for 5 or 10 years.
If you are not familiar with taking a daily vitamin or pill, your doctor or another member of your healthcare team may be able to recommend tips to help you remember to take your hormonal therapy pill every day.
Friese, C, Pini, T, Li,Y. Adjuvant endocrine therapy initiation and persistence in a diverse sample of patients with breast cancer. Breast Cancer Research and Treatment; 2013; 138 (3): 931-9.