Predictive Role of Preoperative Whole-Body 18F-FDG PET/CT for Risk Stratification of Early-Stage (FIGO I-IIA)...

The aim of the present study was to investigate the predictive value of maximum standardized uptake value (SUV_max) measured on preoperative ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in International Federation of Gynecology and Obstetrics (FIGO 2009) stage I-IIA cervical cancer patients who were treated with radical hysterectomy.

A total of 47 patients with FIGO stage I-IIA cervical cancer who were evaluated preoperatively with biopsy and ¹⁸F-FDG PET/CT followed by radical hysterectomy were included in the study. Correlation between SUV_max and pathological risk factors or survival was studied.

The mean SUV_max was significantly higher in patients with large tumor size (≥4 cm), advanced stage (IIA>IB>IA) and depth of invasion >50%. No significant difference was noted in SUV_max between patients with and without pelvic lymph node involvement (P=0.639). SUV_max of the primary tumor with and without lymph-vascular invasion were 12.95 and 10.35, respectively (P=0.5). No significant difference was noted between patients with high SUV_max and low SUV_max with regards to overall survival (OS) and disease-free survival (DFS), using an optimal cut-off value of 7.65 for OS and DFS obtained from receiver operating characteristic (ROC) curve analysis. Patient with tumor size >4cm had 5.9 times more probability of mortality compared to tumor size <4cm (P=0.09).

The present study observations showed that although SUV_max is associated with pathological variables, it does not independently predict oncological outcomes in FIGO stage IA-IIA cervical cancer patients who were treated with radical hysterectomy. These findings suggest that SUV_max of primary tumor may be used for risk stratification, but not for prognostication in surgically treated early-stage cervical cancer patients. Not using other parameters of ¹⁸F-FDG PET/CT like metabolic tumor volume (MTV), tumor lysis glycolysis (TLG), small sample size, variation in calculation of SUV_max, histopathologic heterogeneity, inclusion of stage IA patients in the study were constraints of present study. Further studies with large sample size using multi metabolic parameters of ¹⁸F-FDG PET/CT, including the SUV_max,SUV_mean,SUV_peak, MTV and TLG are needed.