Preoperative extent of peritoneal metastases affects overall survival in ovarian cancer despite complete interval cytoreductive surgery

Abstract

Objectives: We investigated whether the extent of peritoneal metastases, as expressed by the 7 Region Count (7RC), and other surgical findings are predictive of the completeness of interval cytoreductive surgery (CRS) and overall survival in patients with advanced ovarian cancer. Methods: This single center retrospective cohort study included consecutive patients with FIGO stage III-IV epithelial ovarian, fallopian tube, or primary peritoneal cancer who had received neoadjuvant chemotherapy and were planned for interval CRS between January 2013 to April 2019. The gynecological oncologists routinely recorded the 7RC during surgical exploration to systematically quantify the extent of peritoneal metastases. Baseline, treatment and follow-up data were extracted from the local electronic patient database. Logistic regression analysis was performed to predict surgical outcome and cox regression analysis for survival. Results: 317 patients were included for analysis. At exploratory laparotomy with intent to perform interval CRS, the median 7RC was 4 (interquartile range: 2-6). Complete CRS was achieved in 58% of patients and optimal CRS was achieved in 30% of patients. The 7RC showed an AUC 0.81 (95% CI: 0.74-0.88) for predicting at least optimal CRS. After multivariate logistic regression, non-bowel abdominal organ involvement, preoperative CA-125 levels, and involvement of the small bowel or mesentery were shown predictive of complete or optimal CRS additionally to the 7RC. From this model an AUC was achieved of 0.902 (95% CI: 0.85-0.95), which was significantly higher than the 7RC alone (p<0.001). The most effective model of overall survival included the 7RC with a hazard radio of 1.14 (95% confidence interval: 1.05-1.24) as well as surgical outcome with a hazard radio of 1.78 (95% confidence interval: 1.40- 2.27). Other important factors that were included were FIGO stage, age, involvement of the colon, involvement of the small bowel or mesentery and ASA physical status. The median follow-up was 21 months (interquartile range: 12-34 months). Conclusions: The extent of peritoneal metastases, as expressed by the 7RC, is not only a strong predictor for complete or optimal interval CRS but also has an independent prognostic value regardless of the completeness of cytoreduction. Currently, the 7RC is being evaluated on preoperative imaging to incorporate in preoperative decision making. We investigated whether the extent of peritoneal metastases, as expressed by the 7 Region Count (7RC), and other surgical findings are predictive of the completeness of interval cytoreductive surgery (CRS) and overall survival in patients with advanced ovarian cancer. This single center retrospective cohort study included consecutive patients with FIGO stage III-IV epithelial ovarian, fallopian tube, or primary peritoneal cancer who had received neoadjuvant chemotherapy and were planned for interval CRS between January 2013 to April 2019. The gynecological oncologists routinely recorded the 7RC during surgical exploration to systematically quantify the extent of peritoneal metastases. Baseline, treatment and follow-up data were extracted from the local electronic patient database. Logistic regression analysis was performed to predict surgical outcome and cox regression analysis for survival. 317 patients were included for analysis. At exploratory laparotomy with intent to perform interval CRS, the median 7RC was 4 (interquartile range: 2-6). Complete CRS was achieved in 58% of patients and optimal CRS was achieved in 30% of patients. The 7RC showed an AUC 0.81 (95% CI: 0.74-0.88) for predicting at least optimal CRS. After multivariate logistic regression, non-bowel abdominal organ involvement, preoperative CA-125 levels, and involvement of the small bowel or mesentery were shown predictive of complete or optimal CRS additionally to the 7RC. From this model an AUC was achieved of 0.902 (95% CI: 0.85-0.95), which was significantly higher than the 7RC alone (p<0.001). The most effective model of overall survival included the 7RC with a hazard radio of 1.14 (95% confidence interval: 1.05-1.24) as well as surgical outcome with a hazard radio of 1.78 (95% confidence interval: 1.40- 2.27). Other important factors that were included were FIGO stage, age, involvement of the colon, involvement of the small bowel or mesentery and ASA physical status. The median follow-up was 21 months (interquartile range: 12-34 months). The extent of peritoneal metastases, as expressed by the 7RC, is not only a strong predictor for complete or optimal interval CRS but also has an independent prognostic value regardless of the completeness of cytoreduction. Currently, the 7RC is being evaluated on preoperative imaging to incorporate in preoperative decision making.