The Search for Better SERMs Continues

BUFFALO, NY—Breast cancer offers a paradigm for cancer prevention issues. It has been shown that lower exposure to estrogen results in a lower risk of breast cancer. However, a decrease in overall estrogen may pose health risks for women such as increased risk for heart disease. Thus, patients and physicians must evaluate all options available, said Richard M. Elledge, MD, medical director of the Breast Care Center at Baylor College of Medicine-The Methodist Hospital, Houston.

“Selective estrogen receptor modulators (SERMs) offer a potential method to interrupt the transformation of normal breast tissue into cancer. But the currently available SERMs such as tamoxifen [Nolvadex] do not meet all of our needs. There is still work to be done to create the ‘ideal’ preventive agent,” Dr. Elledge said at the New Horizons in Cancer Prevention Symposium, hosted by Roswell Park Cancer Institute.

An ideal SERM would be antiestrogenic in both the breast and uterus, maintain bone density, decrease cholesterol levels, be estrogenic in the brain, have no effect on clotting, and sustain this profile over time.

“The SERM currently approved for prevention, tamoxifen, only meets part of the criteria for an ideal SERM. Its negative effect in the uterus and its inability to remain antiestrogenic after long-term use make it useful for now, but it is not the answer we need,” Dr. Elledge said.

Newer SERMs, such as raloxifene (Evista), may be closer to the ideal profile, but only long-term clinical trials such as STAR (Study of Tamoxifen and Raloxifene) will answer this question, he said. There is also a real need for validated biomarkers to better identify effective agents in a faster period of time, he said.

“The possibility of side effects limits the general use of SERMs. We need better methods of identifying patients who need to consider the use of preventive SERM therapy; we need to deal with the other obstacles to the widespread use of these drugs; and we need to find a way to get these answers faster so we can help women make the best choice for their care,” Dr. Elledge said.