The prognostic value of the chemotherapy response score in tubo-ovarian or primary peritoneal high-grade serous carcinoma (466)

Abstract

<b>Objectives:</b> The purpose of the study was to evaluate the prognostic value of a two-tiered chemotherapy response score (CRS) system on progression-free and overall survival in high-grade serous ovarian cancer patients using traditional survival type analysis. <b>Methods:</b> Retrospective chart data were collected from all patients aged 18 and older with FIGO stage III or IV tubo-ovarian high-grade serous carcinoma undergoing neoadjuvant chemotherapy (NACT) at a single institution from January 2017 to January 2021. A two-tier scoring system was used in which patients were stratified to either CRS 1-2 (no or minimal response to neoadjuvant chemotherapy) or CRS 3 (appreciable or near-complete response). These data were used to compare progression-free and overall survival between the patients in each subgroup using survival analysis (log-rank test). Survival data were adjusted for covariates as appropriate with a Cox regression model. <b>Results:</b> We identified 80 women who met the inclusion criteria above; 97% (<i>n</i>=78) were Caucasian, and the mean age was 66 years (range: 25-87). Baseline demographic data were similar between patients with CRS 1-2 (<i>n</i>=58) and patients with CRS 3 (<i>n</i>=22). More women with CRS 3 underwent an aborted attempt at cytoreduction or surgery for bowel obstruction at the time of diagnosis (<i>n</i>=3 compared to none in the CRS 1-2 cohort). Overall, 74% (<i>n</i>=58) of patients achieved a partial response on platinum-based NACT. About 23% (<i>n</i>=5) of patients with CRS 3 had a complete response compared to only 12.5% (<i>n</i>=7) of CRS 1-2. Overall a greater percentage of patients in the CRS 3 group (95%, <i>n</i>=21) achieved optimal cytoreduction compared with patients in CRS 1-2 (74%, <i>n</i>=43). <i>BRCA1</i> or <i>2</i> mutation frequencies were similar in both CRS subgroups. The majority of women recurred (73%, <i>n</i>=59) regardless of the CRS subgroup. Ultimately five patients were excluded from the analysis of progression-free and overall survival due to pertinent missing information such as documented CRS or missing vital statistics. The mean time from diagnosis to recurrence was 16 months versus 19 months for CRS 1-2 compared to CRS 3, but this difference was not significant. Median time from interval debulking to recurrence was not different between groups (11 months for CRS 1-2 vs 13 months for CRS 3, p=0.21). There was no difference in overall survival between the two groups; mean survival was 35 months in CRS 1-2 versus 34 months in CRS 3 (p=0.86). <b>Conclusions:</b> Previous studies have suggested a difference in progression-free survival for women who had CRS 1-2 versus CRS 3, indicating that this scoring system can inform disease prognosis and may help to guide adjuvant treatment strategies. Our preliminary analysis revealed no statistically significant difference in progression-free or overall survival for patients with CRS 1-2 versus CRS 3 and did not replicate the findings of other studies, a discrepancy that warrants further investigation.