Our group performed a comprehensive meta-analysis looking at the association of achievement of pathologic complete response following neoadjuvant chemotherapy with long-term survival outcomes. Our study included 52 studies and over 27,000 patients and we confirmed what has been reported in the past through prior studies that the achievement of pathologic complete response on an individual level is associated with significantly improved event free survival and overall survival.

It was a meta-analysis, we did a search of PubMed to identify eligible studies. Our key criteria were that the studies had to have 25 patients or more, they had to be focused on localised breast cancer and they had to feature neoadjuvant chemotherapy. They had to, in addition to reporting the pathologic complete response rates, they had to report long-term outcomes by pCR status.
We performed a specific analysis looking at the subgroup of patients who achieved a pathologic complete response and then went on to either receive additional cytotoxic chemotherapy following surgery or did not receive additional cytotoxic chemotherapy following surgery. We found that those groups did equally well and that shows that the achievement of pathologic complete response is prognostic and that perhaps this can help support the de-escalation strategies that are ongoing.

Overall our study results support clinical trials looking at escalation and de-escalation strategies. The hope is that if more patients can achieve a pathologic complete response perhaps with less cytotoxic chemotherapy that we can then spare them unnecessary therapies.