Aromatase inhibitors as adjuvant treatment of breast cancer

The development of the novel, third-generation aromatase inhibitors and inactivators represents a major improvement of endocrine therapy in breast cancer. Subsequent to phase III studies revealing clinical superiority of these drugs compared to conventional therapy as second- and first-line treatment for advanced disease, several randomised studies have found these compounds, administered either as monotherapy or in sequence with tamoxifen, to improve relapse-free survival compared to tamoxifen monotherapy in the adjuvant setting. Notably, we lack data on long-term follow-up with respect to efficacy as well as side effects, and there are currently no data on head to head comparisons between the different aromatase inhibitors. Several critical issues, like influences of treatment on bone and blood lipid profiles underline the need for long-term follow-up with respect to clinical events like bone fractures and cardiovascular events. Finally, we need data on cost-utility with respect to the different strategies as well as with respect to patient age and risk profile.