Source: DGNews  |  Posted 4 years ago

By Jill Stein

BARCELONA, SPAIN -- September 27, 2007 -- New data confirm that tamoxifen use and increased duration of tamoxifen therapy reduce the likelihood of death from breast cancer, according to findings reported here at the 14th European Cancer Conference (ECCO).

Colin McCowan, MD, Research Fellow, Division of Community Health Sciences, University of Dundee, Scotland, and colleagues conducted a retrospective cohort study of all women with incident breast cancer in the Tayside Region of Scotland between 1993 and 2002.

"Nonadherence to prescribed medication for patients with chronic conditions is a major public health issue and many studies have shown worse clinical outcomes associated with low adherence," Dr. McCowan noted in his presentation on September 27th. "Little is known about adherence to tamoxifen in a community setting and the potential effect of a lack of adherence on outcomes."

Tamoxifen at a dose of 20 mg once daily is recommended for 5 years to decrease the risk of breast cancer recurrence and mortality.

Of the 2,080 women in the entire cohort, 1,633 (79%) had been prescribed tamoxifen as adjuvant therapy. Median duration of tamoxifen use was 2.42 years.

Patients were generally adherent to their medication during treatment (median 93%). However, 599 (37%) patients who were prescribed tamoxifen over the study period stopped taking the medication. In fact, for women who were followed for 5 years or more, adherence with tamoxifen therapy was modest (49%).

The study also showed that increased duration of tamoxifen use was associated with improved survival. In a survival model for all-cause mortality, patients who did not use tamoxifen had a higher risk of death after the researchers adjusted for all other covariates (HR = 1.50).

"Compliance with tamoxifen prescribing may not reflect national recommendations, and failure to take tamoxifen may result in a greater risk of death," Dr. McCowan said.

He added that the study also carries implications for compliance with other oral anticancer agents.

[Presentation title: Tamoxifen Adherence and Its Relationship to Mortality in Women With Breast Cancer. Abstract 1213]