The blogwaves were buzzing recently with the news that tamoxifen (nolvadex), the once (and perhaps future) king of breast cancer prevention drugs, is showing legs as the years go by and studies of its long-term effects become clearer. A recent article in the British Journal of the National Cancer Institute reveals that tamoxifen reduced the incidence of breast cancer in the study group by 32% after 4 years; by 27% after 8 years; and by 39% after 13 years, a full eight years after the women in the study had stopped taking the drug. All of these reductions occurred in women with estrogen-receptive cancer; for those with non-estrogen-receptive cancer, tamoxifen doesn’t appear to be lower risk.
One interesting result of the study was the fact that tamoxifen has a greater protective effect in women aged 50 or younger, as well as in pre-menopausal women of any age. The study’s authors proposed that for women identified as having an elevated breast cancer risk, due to family history or other predictors, tamoxifen could be a viable prevention tool. (Some of the predictors mentioned in the study included age of first period, age of first birth and, interestingly, height.) Although there’s no way of knowing if a woman will develop estrogen-receptive (vs. non-receptive) breast cancer, they suggest that, because of the fairly low risk of harmful side effects in younger women, tamoxifen should be strongly considered.
In addition, the authors suggest a successful strategy might include lowered doses of tamoxifen, or taking it in cycles (2 years on, 2 years off); as well as following tamoxifen with an aromatase inhibitor, post-menopause.
In addition, the success of therapy using a tamoxifen/chemotherapy combination was revealed in the April 4 issue of the Journal of the National Cancer Institute. An English study involving nearly 4,000 women with early-stage breast cancer found that patients who took tamoxifen for 5 years, AND had chemotherapy as well, showed “modest yet sustained improvement in both relapse-free and overall survival,” compared to those who took tamoxifen alone. The effect was especially marked in women younger than 50. The study also showed that tamoxifen combined with “ovarian suppression” (surgery, radiation therapy, or drug treatment to stop the functioning of the ovaries) was beneficial to women under 40 with ER-receptive tumors. Seems like tamoxifen is becoming an all-purpose breast cancer wonder drug.
It’s surprising, then, that tamoxifen, though so many of us are taking or have taken it, seems to be losing its preeminent position as the breast cancer prevention drug of choice. Aromatase inhibitors are being prescribed by many doctors, particularly American doctors, to post-menopausal women as part of their initial treatment. Where tamoxifen was regularly prescribed for 5 years in the past, many women have cut their course short and switched to an AI over the last several years. AIs have suddenly become the sexy drug du jour, despite information, such as that in the British study, that tamoxifen has long-term, very positive benefits. What’s going on here?