The largest study to investigate the tolerability of the breast cancer drug tamoxifen in male breast cancer patients has shown that men stop taking their prescribed therapy early because of problems with side effects caused by the drug.
The authors of the research paper, published in the cancer journal Annals of Oncology, looked at records of 64 male breast cancer patients at their institution who had received tamoxifen for an average of four years and found that 53% (34) of the patients experienced one or more drug-related side effects.
Of these 64 patients, 20.3% (13) of the men discontinued taking their prescribed tamoxifen therapy early because of the side effects.
The research suggests that male breast cancer patients who discontinue tamoxifen therapy early may have an increased risk of the cancer recurring.
Tamoxifen is the standard of care for the hormone treatment of men with breast cancer and works by blocking the growth-promoting action of the hormone oestrogen on the cancer cells.
Almost all (90%) breast cancers in men are hormone-receptor-positive and drugs that target the hormone oestrogen are usually given after surgery.
“This is the largest study to specifically assess tamoxifen-related side effects in men because in our institution we treated a relatively large number of male breast cancer patients,” said Dr Naveen Pemmaraju from the Department of Breast Medical Oncology at the University of Texas MD Anderson Cancer Center, Houston, USA.
“We found that, after adjusting for patient age and stage of the disease, the prognosis for men with breast cancer is similar to that of women.
“Tamoxifen has been shown to improve survival rates for breast cancer patients, so early discontinuations may have the potential to increase the risk of the cancer recurring in this group of male breast cancer patients.
“As there are so few male breast cancer cases, clinical practice and optimal treatment strategies have been extrapolated from female breast cancer patients with very little published evidence to guide clinical decisions.
“In our institution, we noted that several of our male patients were having difficulty with taking tamoxifen therapy, and these side effects appeared to be a little bit different to those reported with women receiving the same drug.”