Half of women fail to finish tamoxifen course

A British study has revealed that half of women prescribed tamoxifen fail to finish the recommended 5-year-long course of treatment.

Professor Alastair Thompson and colleagues at the University of Dundee studied prescription records of 2080 women prescribed tamoxifen after undergoing surgery for breast cancer to examine adherence rates and to determine whether adherence influenced survival.

Results showed that 10% of women stopped taking tamoxifen after just one year, by two years that figure had risen to 19%, and by three-and-a-half years 32% had stopped taking the drug. In total, 51% of women failed to finish the five-year-long course of treatment recommended to them in order to maximize their chances of survival.

The results also showed that 20% of women regularly forget to take their medication, a finding which is also worrying as research has shown that women who miss one tablet in five are 10% more likely to die than women who do not forget to take the drug.

The researchers concluded: “Increased duration of tamoxifen reduces the risk of death, although one in two women do not complete the recommended 5-year course of treatment. A significant proportion of women have low adherence to tamoxifen and are at increased risk of death.”

McCowan C, Shearer J, Donnan PT, Dewar JA, Crilly M, Thompson AM, Fahey TP. Cohort study examining tamoxifen adherence and its relationship to mortality in women with breast cancer. British Journal of Cancer. Advance online publication 4 November 2008; doi: 10.1038/sj.bjc.6604758