1) Around 60-70% of breast cancer patients have estrogen receptor positive tumors, making them candidates for hormonal therapy which has been shown to improve survival rates.
2) Tamoxifen is the standard adjuvant hormonal therapy and has been shown to reduce breast cancer recurrence rates by 24-43% and mortality by 14-23% depending on duration of therapy.
3) Aromatase inhibitors like letrozole and anastrazole are also used as adjuvant therapy and have been shown in trials to further reduce recurrence rates compared to tamoxifen alone.