Early recurrence risk: aromatase inhibitors versus tamoxifen

Abstract

Aromatase inhibitors (AIs) are becoming the hormonal treatment of choice for postmenopausal women with early breast cancer. Large, well-controlled clinical studies have established the efficacy and safety of initial adjuvant therapy with letrozole or anastrozole versus the previous standard of 5 years of adjuvant tamoxifen and support using an AI (exemestane, anastrozole or letrozole) following tamoxifen for 2-3 years (early 'switch' treatment) or 5 years (extended adjuvant treatment). Reducing recurrence risk is a primary goal of adjuvant hormonal therapy. There is an early peak of recurrences 2 years after surgery; most are distant metastases rather than local or regional events. Therefore, treatment strategies such as initial therapy with AIs, which reduce early distant recurrence events, can be expected to improve long-term survival outcomes. Switching to an AI following 2-3 years of initial adjuvant tamoxifen is an effective option for patients unable to begin treatment with an AI.

Pathways to Breast Cancer Recurrence

“…Data from clinical studies have suggested a usefulness of aromatase inhibitors in preventing early stage distant metastases, and, therefore, it has been proposed that initial therapy involving adjuvant use of aromatase inhibitors can be beneficial against tumor recurrence [160, 161]. For many years, a five-year administration of tamoxifen has been the gold standard for endocrine therapy in ER-responsive breast cancer patients, and this notion is increasingly being challenged with the inclusion of aromatase inhibitors in the initial years of therapy [162].…”

Deregulation of the EGFR/PI3K/PTEN/Akt/mTORC1 pathway in breast cancer: possibilities for therapeutic intervention

“…Another common treatment option for breast cancer consists of a hormonal-based approach [ 255 ]. Many early stage breast cancers overexpress various isoforms of the ER, making their growth dependent on estrogen.…”

FDG Avidity at PET/CT During Adjuvant Hormonal Therapy in Patients With Breast Cancer

“…Therefore, treatment strategies such as initial therapy with AIs, which reduce early distant recurrence events, can be expected to improve long-term survival outcomes. 8 Prompt and appropriate use of hormonal or cytotoxic drugs can reduce or delay tumor-related syndromes.…”