Approximately half of male breast cancer patients treated with tamoxifen report side effects including weight gain and sexual dysfunction. These adverse effects influence more than 20% of male patients to discontinue treatment, according to researchers at The University of Texas MD Anderson Cancer Center. The study, published recently in Annals of Oncology, is the largest to date of how men with breast cancer tolerate the estrogen-blocking drug.
“While tamoxifen is effective in treating breast cancer in men, little is known about its toxicity,” said Sharon Giordano, MD, associate professor of medicine in MD Anderson’s Department of Breast Medical Oncology and senior author of the study. “This research will help doctors and patients better understand the side effects men experience. With this information, patients can make more informed decisions about treatment risks and benefits.”
Researchers studied the medical records of 64 male breast cancer patients with diagnoses including stages I, II, and III. Patients were treated with tamoxifen for an average of 4 years.
Study results included:
- More than half of the patients (53%) had 1 or more drug-related side effect
- Weight gain (22%) and sexual dysfunction (22%) were the top 2 patient complaints
- Due to adverse effects, 20% of men discontinued the drug prematurely
- Four of 13 men who stopped taking tamoxifen early were directed by physicians to discontinue for medical reasons
Lead author Naveen Pemmaraju, MD, saw a number of these patients. According to him, men and women seem to suffer different side effects, and that may be due to the differences in hormonal environment.
However, further study showed that the outlook for men with breast cancer taking tamoxifen is comparable to that of women.
Pemmaraju suggests doctors counsel patients regarding the drug’s side effects and the benefits of continuing the medication.
“I hope this study will help raise awareness in patients and physicians, generate discussion about the side effects and begin to tease out details of why treatment is discontinued,” he said.