Relevance of Pathological Complete Response after Neoadjuvant Therapy for Breast Cancer

Breast cancer is a heterogeneous disease, and the different biological subtypes have different prognostic impacts. Neoadjuvant trials have recently become popular as they offer several advantages compared to traditional adjuvant trials. Studies have shown that patients who achieve pathological complete response (pCR) after neoadjuvant treatment have a better long-term outcome. Consequently, increasing the rate of pCR became the end point of neoadjuvant trials with the expectation of translation into improved survival. However, the definition of pCR has lacked uniformity, and the prognostic impact of achievement of pCR on survival in different breast cancer subtypes is uncertain. In this review, we present the controversies associated with the use of pCR as an end point in neoadjuvant trials.