18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) predictive score for complete resection in primary cytoreductive surgery

Objective To assess the value of preoperative 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) scan, combined with clinical variables, in predicting complete cytoreduction in selected patients with advanced ovarian cancer. Methods We carried out a multicenter, observational, retrospective study evaluating patients who underwent primary cytoreductive surgery for advanced ovarian cancer in two Spanish centers between January 2017 and January 2022. Inclusion criteria were histological confirmation of invasive epithelial ovarian carcinoma; preoperative International Federation of Gynecology and Obstetrics (FIGO) stage III or IV; upfront cytoreductive surgery; and 18 F-FDG PET/CT performed 1 month prior to surgery. A modified 18 F-FDG PET/CT peritoneal cancer index score was calculated for all patients. Clinical variables and preoperative 18 F-FDG PET/CT findings were analyzed and a multivariate model was constructed. A predictive score based on the odds ratio of the variables was calculated to determine patient selection. Results A total of 45 patients underwent primary cytoreductive surgery. Complete resection was achieved in 36 (80%) patients. On multivariate analysis, two clinical variables (age ≥58 years and American Society of Anesthesiology score ≥3) and two preoperative 18 F-FDG PET/CT scan findings (presence of extra-abdominal lymph node involvement and modified peritoneal cancer index value of 6 or more) were associated with gross residual disease. For this multivariate model predictive of non-complete cytoreduction, the area under the curve was 0.881. A predictive value of ≥5 was the most predictive cut-off for gross residual disease. Complete resection rate was 91.7% in patients with a score of ≤4 and 33.3% in patients with a score of ≥5 points on the predictive score. Conclusions In selected patients, a predictive score value ≥5 may be consider as a cut-off point for triaging patients to diagnostic laparoscopy before the primary surgery or neoadjuvant chemotherapy.