Tolerability and Adherence to Hormonal Therapy Difficult to Asses in Patients with Early Breast Cancer

Although hormonal therapy with aromatase inhibitors (AI) is highly effective at preventing recurrence in menopausal women with breast cancer, several studies have shown that adherence leaves something to be desired. In a study presented at SABCS, patients reported a variety of bothersome symptoms that may have compromised adherence, but physicians often did not record these symptoms in medical records.

“The study suggests that physicians have a hard time accurately determining a patient’s tolerance to AI treatment, and consequently, whether they are adherent,” said Anne Meunier, MD, Centre Léon-Bérard-Clinique Charcot, in Lyon, France, who presented results of a prospective, single-center study of patients with early breast cancer on AI treatment. “Physicians need to spend time to explain what to expect from the treatment and benefit versus risk, but the final decision belongs to the patient,” she said.

The study was based on patients’ self-reported answers to written questionnaires about tolerance and adherence. If a patient discontinued therapy, she was asked to specify reasons for discontinuing treatment in her response to the questionnaire. Patients completed questionnaires at the end of each medical visit without the physician present.

Of 450 post-menopausal women included between December 2005 and December 2007, 300 were eligible for the adherence study. Median age was 59 years (range, 40-82 years). Cancer stage was I in 40.5%, II in 46.8%, and III in 12.7%. Two percent of the population was non-menopausal, and these women received gonadotropin-releasing hormone analogs. AIs used were anastrozole (71.3% of cases), letrozole (17.3% of cases), and exemestane (11.3%). Tamoxifen had been initially prescribed to 30.8% of patients.

At a median follow-up of 23.1 months (range, 2.1 to 58.8 months), the median number of questionnaires per women was 1.46 (range, 1 to 5). The women reported a variety of side effects. Insomnia was almost universal (98.7%), and other common side effects included arthralgia (85.3%), fatigue (72%), memory troubles (59.7%), concentration difficulties (55.3%), hot flushes (63.3%), decreased libido (56.7%), ocular complaints (50%), and fracture (5%). Although most of these complaints are commonly accepted side effects of AIs, others are not typically mentioned in the literature, such as ocular complaints.

A significant disparity was observed between patients’ reports of symptoms/complaints and physicians’ records of their complaints. “The side effects reported by the women are either not told to their doctor or not considered significant by the doctors,” Dr. Meunier said. For example, 98.7% of patients reported insomnia, whereas medical reports listed insomnia in only 3.6%; 59.7% reported memory troubles, compared with 1.3% according to medical reports; and 56.7% of patients reported decreased libido, compared with only 0.7% in medical reports.

Adherence rates were higher in this study than in several previous studies of AIs, Dr. Meunier said, “but the way information was collected is questionable, because self-reported adherence underestimates non-adherence.” At first visit, adherence was high (>3 months after initiation), 81.4% of patients said they were taking their medication daily. At the second medical visit, 82.3% said they were fully compliant. However, 6.1% interrupted treatment at visit 1 and 8.8% by visit 2. The main reasons for discontinuation at visit 1 and 2, respectively, was poor tolerance/side effects (41.2% and 25%.