Introduction: The development of resistance to therapy is a concern in all three subtypes of breast cancer (BC). Yet, outcomes of patients with BC have improved in the past few years thanks to a molecularly targeted approach and a greater understanding of the many mechanisms through which cancer cells adapt to evade drug therapies. Indeed, there have been a number of different and active treatment strategies for hormone receptor positive (HR+ and Her2 positive BC although triple-negative breast cancer treatment remains problematical because of the early onset of resistance to treatments and the limited availability of targeted treatment options.
Areas covered: Herein, the authors present the various pharmacotherapeutic options for refractory breast cancer including their perspectives on these options.
Expert opinion: In recent years, there has been significant progress in our understanding of the biological mechanisms that cause resistance to BC treatments. The targeted therapeutic approach particularly has improved patient outcomes for those with refractory BC, but some unresolved issues still remain. In particular, we need to identify biomarkers of resistance to better tailor treatments, toxicities, and costs. Moreover, we need to determine the best sequence of treatments in refractory BC patients.
Keywords: antiHer2 therapy; breast cancer; de novo resistance; endocrine therapy; immunotherapy; secondary resistance; targeted therapies.