Higher Copayments May Limit Use of Breast Cancer Therapy

It appears that women with early breast cancer who are prescribed treatment with aromatase inhibitors (AIs) are more likely to discontinue or not follow through with this therapy if insurance copayments are high. These results were presented at the 2010 San Antonio Breast Cancer Symposium.

Treatment of hormone receptor-positive breast cancer often involves hormonal therapies that suppress or block the action of estrogen. These therapies include tamoxifen as well as agents known as aromatase inhibitors. Tamoxifen acts by blocking estrogen receptors, whereas aromatase inhibitors suppress the production of estrogen in postmenopausal women.

It’s not uncommon for women to fail to adhere to treatment with hormonal therapy. Previous studies have indicated that a woman’s age, the severity of side effects of hormonal therapy, and whether or not she believes the medicine is effective can influence her adherence to treatment. Little is known, however, about how the expense of these therapies may affect rates of adherence.

The impact of insurance copayments on adherence to AIs was evaluated in a study of 8,110 women aged 50 to 65 and 14,050 women aged 65 and older. The researchers investigated two different types of non-adherence: whether patients stopped using AIs entirely and didn’t get any refills or whether patients did not take AIs as prescribed (did not refill prescription on time or did not take AIs at least 80% of the time). Researchers categorized copayments as follows: less than $30, between $30 and $89.99, and $90 or more.

21.2% of the 8,110 patients aged 50 to 65 stopped taking AIs.Of the patients aged 50 to 65 who stayed on treatment during a two-year period, 10.3% did not take AIs as prescribed.Almost 25% of the 14,050 patients aged 65 and older stopped taking AIs.8.9% of patients aged 65 and older who continued taking AIs did not do so as prescribed. Women 65 years and older were more likely to discontinue AIs if their copayments were greater than $30.Women younger than 65 years became more likely to discontinue AIs when copayments were $90 or greater. It was also noted that when AIs were prescribed by a primary-care doctor, women were less likely to stay on treatment. This was also the case among women prescribed many other medications in addition to AIs.

These results indicate that higher prescription copayments limit the use of AIs, making patients more likely to either discontinue treatment or not take AIs as prescribed and that older women are more likely to be affected. Because AIs can be highly effective, the researchers suggest that “future public policy efforts should be directed towards reducing financial constraints as a means of increasing the complete use of these medications.”

Reference: Hershman DL, Neugut AI, Subar M, et al. Association between prescription co-payment amount and compliance with adjuvant aromatase inhibitor therapy in women with early stage breast cancer. Presented at the 33rd annual San Antonio Breast Cancer Symposium, December 8-12, 2010. Abstract S6-4.

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