Objective To investigate the value of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT metabolic volume parameters metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in predicting the survival and prognosis prediction of patients with recurrent cervical cancer and their relationship with peripheral blood neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR).

Methods The clinical and imaging data of 50 patients (the median age was 52 (45, 66) years) with recurrent cervical cancer who underwent ¹⁸F-FDG PET/CT whole body imaging at the First Affiliated Hospital of Bengbu Medical College from January 2014 to December 2020 were retrospectively analyzed. The volume parameters with maximum standard uptake value (SUV_max) and SUV_max thresholds of 40% and 50% were obtained: whole body MTV40% (wbMTV40%), wbMTV50% and whole body TLG40% (wbTLG40%), wbTLG50%. To evaluate the relationship between these ¹⁸F-FDG PET/CT metabolic volume parameters and progression free survival (PFS) and overall survival (OS), as well as the correlation with peripheral blood NLR and PLR. Patients were divided into three groups based on whether they had recurrence and the risk of death: non recurrence, recurrence, and death. For survival analysis, the patients were divided into risk groups based on their FIGO stage (Ⅰ+Ⅱ vs. Ⅲ+Ⅳ), pathological type (squamous cell carcinoma vs. adenocarcinoma), location of recurrence (pelvic recurrence vs. distant recurrence), initial treatment with radiotherapy (Yes vs. No), postoperative treatment (surgery vs. non surgery), and age at the time of recurrence (≥ 60.0 years vs. <60.0 years). The continuous variables of patients (NLR, PLR, and ¹⁸F-FDG PET/CT metabolic volume parameters) were divided into high and low groups based on the optimal threshold. Chi-square test was used to analyze the differences between groups of categorical variables. Receiver operating characteristic curve was used to evaluate the predictive effect of ¹⁸F-FDG PET/CT metabolic volume parameters on PFS and OS and determine the optimal critical value. Youden index method was used to determine the optimal critical value, and the optimal ¹⁸F-FDG PET/CT metabolic parameters were then determined. Kaplan-Meier method was used to draw the survival curves of PFS and OS, and Log-rank method was used to test the inter-group survival curve. Cox regression model was used to conduct univariate and multivariate analysis of various possible prognostic factors in patients with recurrent cervical cancer. The independent predictors of PFS and OS were obtained by incorporating P<0.05 variables from a single factor analysis into a multivariate regression analysis. The correlation between ¹⁸F-FDG PET/CT metabolic parameters and peripheral blood NLR and PLR was analyzed by Spearman correlation analysis.

Results There was a statistically significant difference between the groups with or without relapse and the risk of death in the initial treatment of all patients (χ²=26.386, P=0.003). Compared with patients in the non recurrence group, patients in the recurrence and death groups had a significant increase in PLR, and the difference was statistically significant (χ²=29.528, P=0.001). WbMTV50% had higher predictive power for PFS and OS than other metabolic parameters, with a critical value of 25.24 cm³ and an area under curve (AUC) of 0.753 (95%CI: 0.611 to 0.864, P=0.009) for PFS prediction. The critical value of wbMTV50% for predicting OS was 27.36 cm³, AUC=0.780 (95%CI: 0.640 to 0.885, P<0.001). The critical value of PLR for predicting PFS was 188.2, AUC=0.708 (95%CI: 0.562 to 0.868, P=0.037), sensitivity was 87.5%, and specificity was 50.5%. The critical value of PLR for predicting OS was 213.5, AUC=0.678 (95%CI: 0.531 to 0.803, P=0.021), sensitivity was 62.1%, and specificity was 76.0%. Cox multivariate analysis showed that wbMTV50% (HR=0.260, P=0.003), PLR (HR=0.380, P=0.031) and radiotherapy at initial treatment (HR=0.209, P=0.014) were independent predictors of PFS, whereas wbMTV50% (HR=0.103, P<0.001) and PLR (HR=0.240, P=0.012) were also independent predictors of OS. SUV_max, wbTLG40% and wbTLG50% were moderately correlated with NLR and PLR (r=0.475, 0.542, 0.548, 0.532, 0.599, 0.606; all P<0.001), whereas wbMTV40% and wbMTV50% were moderately to highly correlated with NLR and PLR (r=0.715, 0.629, 0.766, 0.642; all P<0.001). Under the same threshold, the correlation coefficient of wbMTV with NLR and PLR is greater than that of wbTLG.

Conclusions ¹⁸F-FDG PET/CT metabolic volume parameter wbMTV50% is an independent predictor of PFS and OS in patients with recurrent cervical cancer, which is related to peripheral blood NLR and PLR. It can be used as a predictor of the prognosis of recurrent cervical cancer and provide valuable information for the individualized treatment of recurrent cervical cancer.