JCO long term follow up of Tamoxifen

In the JCO:

A very interesting article on the long term benefits of tamoxifen for breast cancer patients, emphasizing the curative nature of adjuvant hormone modulation in breast cancer patients. Also of interest is the reduction in CV events with longer term tamoxifen and the stability of the endometrial cancer risk at ~1.5% for both.

Link and Abstract:

Long-Term Benefits of 5 Years of Tamoxifen: 10-Year Follow-Up of a Large Randomized Trial in Women at Least 50 Years of Age With Early Breast Cancer [Breast Cancer]: "Purpose

The Cancer Research UK 'Over 50s' trial compared 5 and 2 years of tamoxifen in women with early breast cancer. Results are reported after median follow-up of 10 years.

Patients and Methods

Between 1987 and 1997, 3,449 patients age 50 to 81 years with operable breast cancer who had been taking 20 mg of tamoxifen for 2 years were randomly assigned to either stop or continue for an additional 3 years, if they were alive and recurrence free. Data on recurrences, new tumors, deaths, and cardiovascular events were obtained (April 2010).

Results

There were 1,103 recurrences, 755 deaths as a result of breast cancer, 621 cardiovascular (CV) events, and 236 deaths as a result of CV events. Fifteen years after starting treatment, for every 100 women who received tamoxifen for 5 years, 5.8 fewer experienced recurrence, compared with those who received tamoxifen for 2 years. The risk of contralateral breast cancer was significantly reduced (hazard ratio, 0.70; 95% CI, 0.48 to 1.00). Among women age 50 to 59 years, there was a 35% reduction in CV events (P = .005) and 59% reduction in death as a result of a CV event (P = .02); in older women, the effect was much smaller and not statistically significant.

Conclusion

Taking tamoxifen for the recommended 5 years reduces the risk of recurrence or contralateral breast cancer 15 years after starting treatment. It also lowers the risk of CV disease and death as a result of a CV event, particularly among those age 50 to 59 years. Women should therefore be encouraged to complete the full course. Although aromatase inhibitors improve disease-free survival, tamoxifen remains a cheap and highly effective alternative, particularly in developing countries.

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