Chemotherapy Response Score Predicts Surgical Outcome and Prognosis in Tubo-Ovarian/Primary Peritoneal Cancers: A Retrospective Analysis in a Tertiary Care Centre in UK

Aims To assess whether chemotherapy response score (CRS) is associated with surgical end-result in interval debulking surgery (IDS) for tubo-ovarian cancer patients and determine its prognostic significance. Background CRS is a histopathological three-tier score for assessing tumour regression in omentectomy specimens after neoadjuvant chemotherapy (NACT), and original study concluded that prognostically, CRS is more important than completeness of cytoreduction (CC) in IDS. This has not been proved by other validation studies. There is a conflict in evidence regarding significance of improvement of overall survival (OS) with CRS-3 in available literature. Evidence of association of CRS with radiological and biochemical (CA-125 decline) response is lacking and conflicting. Methods Patients who underwent IDS between 2010 and 2017 were retrospectively analysed using omental CRS scoring. Surgical end-result and clinico-pathological data were collected and correlated with CRS. Recurrence was assessed radiologically, OS and progression-free survival (PFS) calculated in the three histopathological subgroups, and compared with clinical variables using Cox proportional hazard model and log-rank test. Results Among 201 patients who underwent IDS, 82 patients had minimal response (CRS-1), 65 moderate (CRS-2) and 54 had excellent response (CRS-3). Seventy-seven patients (38%) had CC and 100 patients had optimal cytoreduction. There was an association between CC and CRS-3 ( p < 0.0001). CRS, along with extent of cytoreduction, independently predicts PFS and OS after IDS. Biochemical response (CA-125 decline after NACT) and radiological response were predictors of chemotherapy response. Conclusion CRS is the most important independent prognostic factor after IDS for PFS, and a post-NACT pre-IDS omental biopsy may help predict completeness of surgery and overall good prognosis.