TAMOXIFEN vs. AROMATASE INHIBITORS FOR MALE BREAST CANCER
In a private conference hosted by the Male Breast Cancer Coalition, our NYCRANEWS editorial team met Dr. Jose Pablo Leone, medical oncologist and researcher at the Dana-Farber Cancer Institute. Discussions covered tamoxifen and aromatase inhibitors for the treatment of male breast cancer, and his research plans in this field.
BACKGROUND
According to the American Cancer Society, a variety of standardized chemotherapy drugs and drug classes are available for (female) breast cancer. These classes include: ANTHACYCLINES [extracted from Streptomyces bacterium used to treat a variety of cancers including leukemias, lymphomas, breast, stomach, uterine, ovarian, bladder cancer, and lung cancers]. In this class are drugs like doxorubicin (Adriamycin) and epirubicin (Ellence). Another class are TAXANES such as paclitaxel (Taxol) and docetaxel (Taxotere). The next are ANTIMETABOLITES like 5-fluorouracil (5-FU) or capecitabine (xeloda). Last are ANTINEOPLASTICS or ALKYLATING Agents like Cyclophosphamide (Cytoxan) and Carboplatin (Paraplatin).
Currently, Tamoxifen remains the only standard of care that is available for men with breast cancer.
Dr. Leone started his review on Tamoxifen vs AI in 2014 in the University of Iowa at the VA hospital where he encountered with many cases of men who had breast cancer undergoing treatment. His interest widely expanded due to the lack of data on how to successfully manage and treat male breast cancer.
INTERVIEW WITH Dr. LEONE: DIFFERING EFFECTS OF BREAST CANCER DRUGS ON MEN vs. WOMEN
There are so many other endocrine therapy options available that are available to women with breast cancer, but none apply for men prior to Tamoxifen. Tamoxifen is recognized as a very good drug and an effective drug for the treatment of breast cancer and both in men and in women. Current research on Tamoxifen for men is designed to collect reactive data to support the exploration of further options.
Tolerance levels vary between men, some showing minimal or no side effects, but others display significant and profound adverse effects. HOT FLASHES for both genders are common with this drug. But as opposed to women who may already have undergone menopause and are familiar with this experience, men have a tough time coping with this issue. In addition, other men-specific side effects appear in higher incidents like fatigue, erectile dysfunction and also the risk of blood clots or deep venous thrombosis or thromboembolic events. These appear higher in men than in women, causing the demand for investigation.
For women, other endocrine therapies exist beyond Tamoxifen. Aromatase inhibitors are a common option either prior to or instead of Tamoxifen. Postmenopausal women can use Tamoxifen for a couple of years and an Aromatase Inhibitor after within a five-year treatment schedule as part of a standard endocrine therapy. Meanwhile, others can use only AI inhibitors for the full five years.
While women have the benefits of switching to AI should they contract side effects from Tamoxifen, men are in a harder situation when making this decision because not enough data about the efficacy of aromatase inhibitors (AI) are available for men. Currently, only retrospective studies are available out there, which are prone to selection bias. We need to do more research to get scientific validity to dictate treatment for patients.
Due to the physiological differences in the endocrine system between men and women, there may be differences in the efficacy of aromatase inhibitors, leaving men with only Tamoxifen as their primary option. Tamoxifen for men is the standard recommended drug for men with metastatic breast cancer. If there is progression of disease after Tamoxifen, then other endocrine therapies can be used in the metastatic setting. This is why we need prospective studies evaluating AI in men.
We are working on a clinical trial of endocrine therapy for male breast cancer. The study will be done in collaboration with the TBCRC and the Male Breast Cancer Coalition. This trial comes from the essential question that we face every day when we take care of men with breast cancer as far as Tamoxifen and alternatives.
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