A post-menopausal woman with hormone receptor-positive, HER2-negative early breast cancer completes 5 years of tamoxifen. The MA.17 trial informs the decision to extend endocrine therapy. What did MA.17 demonstrate?
- A Continuing tamoxifen for 10 total years has no benefit over stopping at 5 years
- B Switching to an aromatase inhibitor after 5 years of tamoxifen improves disease-free survival compared to stopping treatment ✓
- C Ovarian suppression added to tamoxifen reduces recurrence in pre-menopausal women
- D Letrozole started at diagnosis is superior to tamoxifen for post-menopausal patients
Correct answer: B. Switching to an aromatase inhibitor after 5 years of tamoxifen improves disease-free survival compared to stopping treatment
Explanation
The MA.17 trial showed that letrozole (an aromatase inhibitor) given for 5 years after completion of 5 years of tamoxifen significantly improved disease-free and distant disease-free survival in post-menopausal women with hormone receptor-positive early breast cancer. This established the paradigm of extended endocrine therapy. The ATLAS and aTTom trials separately addressed extended tamoxifen, while SOFT/TEXT addressed ovarian suppression.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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