Tamoxifen in the treatment of patients with breast cancer: Results of the latest meta-analysis of prospective randomized clinical trials

A meta-analysis of 55 prospective randomized clinical trials including more than 37,000 patients has analyzed the effectiveness of tamoxifen in the treatment of breast cancer. Standard treatment consists of 20 mg tamoxifen daily for 5 years in patients with either a positive estrogen receptor or a positive progesterone receptor status. This treatment achieves a 50% improvement of the 5-year relapse-free survival and a 28% improvement of the overall survival. Tamoxifen is effective in lymphnode-negative and lymphnode-positive patients as well as in premenopausal and postmenopausal women. The combination of chemotherapy with hormonal treatment is even more effective and brings a further improvement of survival of 50%. In addition, tamoxifen reduces the number of contralateral breast cancer cases to 50%, but increase the occurrence of endometrial cancers from 1.2/1,000 breast cancer patients within 10 years to 4.4/1,000 women. In conclusion, tamoxifen 20 mg daily for 5 years is the standard treatment of hormone receptor-positive breast cancer patients.