How long do you give adjuvant hormonal therapy for women over 70 with breast cancer treated with lumpectomy only?

It is always difficult to make a recommendation for endocrine therapy duration when optimal duration is unknown. Looking at CALGB 9343 (Hughes et al, JCO 2013), in which women with stage I cancers were randomly assigned to either tamoxifen plus radiation or tamoxifen alone, we know that the risk of local recurrence is low regardless of radiation receipt (10% without radiation, 2% with radiation after ten years). Per that protocol, additional hormone therapy beyond 5 years was at the discretion of the treating physician. These women received tamoxifen, not an AI, and we know that AIs are superior, so presumably the risk of local recurrence is even lower with just 5 years of treatment.

The issue of distant recurrence is also interesting; for ...