Excluding non-melanoma skin cancers, breast cancer is the most common form of cancer in women, with an estimated 178,489 new cases diagnosed in 2007, according to the American Cancer Society. Even after standard treatment with tamoxifen, there is a significant risk that the breast cancer will return within 5 years. A recent analysis published in the Journal of Clinical Oncology found that the risk of breast cancer recurrence might be reduced by starting treatment with a drug called letrozole anywhere from one to seven years after taking tamoxifen therapy.

Letrozole is a pill taken by mouth that belongs to a class of drugs called aromatase inhibitors. Analysis of results from a landmark clinical trial of breast cancer patients showed that women who initiated letrozole treatment within several years after completing the recommended five year course of tamoxifen reduced their risk of breast cancer recurrence by 63%. These women also displayed a 61% reduced risk of their breast cancer spreading to other parts of the body. In a separate analysis of results from this same clinical trial published in the Annals of Oncology, researchers found that there was significant benefit in starting letrozole treatment within three months of completing tamoxifen.

It seems that, even with delays, women diagnosed with early stage breast cancer may be able to do more to reduce their risk of disease recurrence after initial treatment with tamoxifen.