Pathological response of ovarian cancer to neoadjuvant chemotherapy.

There is only a few of studies devoted to evaluation of pathologic response of ovarian cancer (OC) to neoadjuvant chemotherapy (NACT). Pathologic complete responses (pCR), which are characterized by the lack of viable tumor cells in surgical specimens, are rarely observed in ovarian carcinomas. Multiple reports demonstrate that pCR is associated with evidently improved disease outcomes. Recommendations of the International Collaboration on Cancer Reporting suggest to use recently developed Chemotherapy Response Scoring (CRS) system, which is based on the pathological analysis of surgically removed omental masses. CRS3 (complete or near-complete response) is characterized by the lack of residual tumor cells in the omentum or presence of tumor foci up to 2 mm maximum size. It is observed after NACT in approximately 30-40% patients with high-grade serous ovarian cancer (HGSOC) and is reproducibly associated with the improvement of the disease prognosis.