Adjuvant endocrine therapy for postmenopausal breast cancer in the era of aromatase inhibitors: an update.

There is overwhelming evidence that optimal adjuvant endocrine therapy for hormone sensitive breast cancer in postmenopausal women should include a third generation aromatase inhibitor (AI). On current evidence, adjuvant anstrozole or letrozole should be used upfront in such patients especially in those with high risk disease (node positive and/or tumours > 2 cm). The sequential approach of tamoxifen for 2-3 years followed by exemestane or anastrozole for 2-3 years is a reasonable alternative to 5 years of AI monotherapy in patients with low risk disease (node negative and tumour smaller than 2 cm) especially if the tumour is positive for estrogen and progesterone receptors.Node-positive patients completing 5 years of adjuvant tamoxifen should be offered letrozole for up 48 months. Further research is required to establish the long-term cardiovascular safety of AIs especially that of letrozole and exmestane, the optimal AI to use, duration of AI therapy and whether monotherapy with an AI for 5 years is superior to sequencing an AI after 2-3 years of tamoxifen. The bone mineral density (BMD) should be measured at baseline and monitored during therapy in women being treated with AIs. Anti-osteoporosis agents should such as bisphosphonates should be considered in patients at high risk of bone fractures.