Premature Tamoxifen Withdrawal Is Common in Male Patients With Breast Cancer

“Clinicians need to be aware of the possible side effects that men may experience when receiving tamoxifen so that patients can be counseled appropriately.”

—Naveen Pemmaraju, MD

New data show that roughly one-fifth of tamoxifen-treated male patients with breast cancer stop treatment early because of side effects.

Naveen Pemmaraju, MD, with The University of Texas MD Anderson Cancer Center in Houston, and colleagues reviewed the records of 64 male patients with breast cancer who had been evaluated at their institution between 1999 and 2009.

The investigators said that, to their knowledge, theirs is the largest retrospective study to date to examine tamoxifen-related side effects in male patients with breast cancer.

Male breast cancer is a rare disease and accounts for <1% of all breast cancer diagnoses worldwide. In the United States, roughly 2000 new cases are diagnosed annually. Breast cancer in men is usually hormone-receptor-positive, and tamoxifen is the standard antihormonal treatment in this population.

Limited data are available on the selection of treatment regimens in male patients with breast cancer and the potential side effects of such treatments. As such, clinical decisions in male patients with breast cancer have been made based on data from female breast cancer studies.

The MD Anderson study included men who were aged ≥18 years and who had been diagnosed with breast cancer of any histological subtype, were stage I-II at diagnosis, and had been treated with tamoxifen with at least 1 follow-up clinic visit with a history and physical after the start of tamoxifen therapy. The median follow-up from the start of tamoxifen therapy was 3.9 years.

Overall, 34 patients (53%) experienced 1 or more tamoxifen-related side effects.

The most common toxicities were weight gain and sexual dysfunction/loss of libido, each of which occurred in 14 patients (22%).

Thirteen patients (20.3%) discontinued treatment because of toxicity. One patient stopped treatment because of ocular side effects, 1 for leg cramps, 2 for neurocognitive deficits, 2 for bone pain, 3 for sexual dysfunction, and 4 for thromboembolic events.

“The results of the study should not change the recommendation for prescribing tamoxifen for male breast cancer patients,” advised Pemmaraju in a news release. “However, clinicians need to be aware of the possible side effects that men may experience when receiving tamoxifen so that patients can be counseled appropriately.”

The researchers called for additional prospective studies to improve knowledge about antihormonal agents in male breast cancer.

Pemmaraju N, Munsell MF, Hortobagyi GN, Giordano SH. Retrospective review of male breast cancer patients: analysis of tamoxifen-related side effects [published online ahead of print November 15, 2011]. Ann Oncol. 2011. doi:10.1093/annonc/mdr459.