Study finds young women less likely to complete hormonal therapy after breast cancer diagnosis

June 29, 2010

In a study of over 8,000 women with estrogen receptor-positive early stage breast cancer who were prescribed hormonal therapy for five years, women younger than 40 years had the highest rate of discontinuation of hormonal therapy.  There were 202 patients younger than 40 years and 32% discontinued therapy by 4.5 years, and of those who continued, 28% did not take the medication on a regular basis. Overall, among all age groups, 30% discontinued therapy early and only 49% fully adhered to the treatment regimen for the 4.5 years of the study period.

Automated pharmacy records were used to identify prescriptions and dates of refills for the women, all patients enrolled in Kaiser Permanente of Northern California.  Of the total 8,769 patients enrolled in the study, 43% were prescribed tamoxifen, 26% were prescribed aromatase inhibitors, and 30% had been prescribed both at some point during the first year after diagnosis.  No differences were found in adherence rates to tamoxifen vs. aromatase inhibitors.  In addition to younger age, age over 65, having had a lumpectomy, and comorbidities were associated with earlier discontinuation of therapy.  Being of Asian race, being married, earlier year at diagnosis, receipt of chemotherapy or radiotherapy, and longer prescription refill interal, were all associated with completion of therapy.

The study was published online in the Journal of Clinical Oncology.  Read a summary of the research and the advocate comments on nonadherence to hormonal medication here.