ESMO 2018: Are Women With Early Breast Cancer Adhering to Hormonal Therapy?
Posted: Monday, October 22, 2018
About 1 in 6 premenopausal women being treated for early-stage breast cancer do not adhere adequately to tamoxifen therapy after 1 year of treatment, according to the prospective French CANTO cohort, which is studying the long-term impact of side effects associated with breast cancer treatments in about 12,000 participants. In fact, those who do not adhere to hormonal therapy may be at increased risk of recurrence and reduced survival. Barbara Pistilli, MD, of the Institut Gustave Roussy, Villejuif, France, presented these findings at the European Society for Medical Oncology (ESMO) 2018 Congress in Munich (Abstract 185O_PR).
Although hormonal therapy such as tamoxifen is recommended for 5 to 10 years in all patients with hormone receptor–positive breast cancer, per the ESMO Clinical Practice Guidelines, many of these women discontinue long-term therapy. “I was surprised at the high rate of nonadherence, which was considerably higher than reported previously,” said Dr. Pistilli in an ESMO press release. “Women with breast cancer should be encouraged to discuss their treatment and any side effects they experience with their doctor to obtain help to take their therapy.”
Dr. Pistilli and colleagues focused on a subgroup of about 1,800 patients prescribed adjuvant hormonal therapy. Their adherence to tamoxifen was assessed at 1, 3, and 5 years by measuring serum levels and then compared with patients’ self-reports of adherence.
About 16% of these women did not adequately adhere to hormonal therapy at 1 years based on assessment of tamoxifen (defined as < 60 ng/mL). And about 10% were found to be nonadherent, with undetectable levels of tamoxifen. An additional 5.3% of patients were identified as poorly adherent, with serum levels of tamoxifen below the steady-state concentration expected after 3 months of treatment. As for patient self-reports, at least 50% of the women with undetectable/low tamoxifen levels did not declare they were not taking their tamoxifen as prescribed.
