After neoadjuvant chemotherapy of breast cancer pathologic complete response (pCR) indicates a favorable prognosis. Among non-selected patients, pCR is, however, achieved in only 10–30%. Early evaluation of tumour response to treatment would facilitate individualized therapy, with ineffective chemotherapy interrupted or changed. | Early prediction of pathologic response to neoadjuvant treatment of breast cancer Use of a cell-loss metric based on serum thymidine kinase 1 and tumour volume