Letrozole Schedules Compared in Postmenopausal Women With Breast Cancer
There appear to be no disease-free survival benefits for extended intermittent use of letrozole, compared with continuous use in postmenopausal women with breast cancer, according to a study published in The Lancet Oncology. The phase III trial, authored by Marco Colleoni, MD, of the European Institute of Oncology in Milan, and colleagues, supports the “safety of temporary treatment breaks in selected patients who might require them.”
The randomized, open-label SOLE trial (conducted in 22 countries) included 4851 postmenopausal women who had completed 4 to 6 years of endocrine therapy for hormone receptor–positive, lymph node–positive, and operable breast cancer. They were randomized to receive either extended intermittent or continuous letrozole over a 5-year period. Because resistance to continuous use of letrozole may be reversed by the withdrawal and reintroduction of the drug, the researchers theorized that extended use might improve breast cancer outcomes.
After a median 60-month follow-up, estimated 5-year disease-free survival rate for intermittent users was 85.8% compared with 87.5% for continuous users. Intermittent users had 5-year freedom from breast cancer rates of 90.9% (vs. 91.2%) and an overall survival rate of 94.3% (vs. 93.7%). The most common grade ≥ 3 adverse events—hypertension and arthralgia—were similar between the two groups.