Examining cancer resections after neoadjuvant chemotherapy

Neoadjuvant chemotherapy is now an established part of therapy for many tumours so as histopathologists we are receiving many more specimens after chemotherapy. This presents a few additional challenges including identifying the site of the original tumour and making some assessment of the tumour response to the chemotherapy. In breast cancer high grade larger tumours, especially those that have amplification of the HER2 gene, are often treated by neoadjuvant chemotherapy. In this month’s Histopathology Sarah Pinder et al., on behalf of the Translational Subgroup of the NCRI Breast Clinical Studies Group, have produced a very useful review article on the handling of breast cancer specimens after neoadjuvant chemotherapy. Their review shows that tumours often regress into small islands of cells scattered throughout the original tumour site so if no macroscopic tumour is present then multiple blocks should be taken from the tumour site (which has hopefully been marked with a clip or similar marker before the start of chemotherapy). They discuss the various definitions of complete pathological response and the different scoring systems that have been described to assess tumour response.