Metabolic parameters with different thresholds for evaluating tumor recurrence and their correlations with hematological parameters in locally advanced squamous cell cervical carcinoma: an observational F-FDG PET/CT study.

BACKGROUND

Positron emission tomography (PET) parameters for a combination of the primary tumor and suspicious metastatic lymph nodes (SMLNs) appear to be more potential than those for the primary tumor alone for evaluating tumor recurrence in locally advanced cervical carcinoma (LACC), while the optimal threshold has not been determined. This study investigated the optimal PET parameters and percentage of SUV (%SUV) thresholds for tumor recurrence evaluation, and the relationship with hematological parameters in patients with LACC treated with concurrent chemoradiotherapy (CCRT).

METHODS

Eighty-nine patients with advanced squamous cell cervical carcinoma (SCCC) scheduled for CCRT underwent pretreatment whole body PET/CT scans. We analyzed PET parameters including maximum standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor (SUV-P, MTV-P, TLG-P) and the combination of the primary tumor and SMLNs (SUV-C, MTV-C, TLG-C). The association between PET parameters with different %SUV threshold and recurrence-free survival (RFS), and the correlations between PET parameters and hematological parameters including squamous cell carcinoma antigen (SCC-ag), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and hemoglobin (Hb) were evaluated.

RESULTS

The optimal threshold for evaluating tumor recurrence was 50%SUV, and the optimal PET parameter was MTV-C with the 50%SUV threshold (MTV-C) (c-index =0.752). Multivariate analysis indicated that MTV-C [hazard ratio (HR), 1.065; P<0.001], NLR (HR, 1.195; P=0.045) and SMLNs (HR, 2.225; P=0.003) were independent risk factors for RFS. MTV and TLG with most of %SUV thresholds had slight-to-moderate correlations with SCC-ag, NLR and PLR. For SCC-ag, MTV-C55% (r=0.500; P<0.001) had the highest correlation coefficient among all parameters. For NLR and PLR, MTV-C (r=0.637 and r=0.515, respectively; P<0.001 for both correlations) received the highest correlation coefficient.

CONCLUSIONS

The MTV-C estimated by using a 50%SUV threshold, which is related to systemic inflammatory response biomarker (NLR and PLR), can be used as an optimal PET parameter associated with tumor recurrence of LACC.