Value of intratumoral metabolic heterogeneity and quantitative ¹⁸F-FDG PET/CT parameters in predicting prognosis for patients with cervical cancer

Objective. The purpose of this study is to evaluate the prognostic value of quantitative metabolic parameters from pretreatment PET/CT scans of patients with squamous cell cervical cancer. Materials and Methods. This retrospective study included 120 patients with biopsy-proven squamous cell carcinoma of the cervix who underwent FDG PET/CT for initial tumor staging. The primary tumor maximum standardized uptake value (SUV_max) and mean standardized uptake value (SUV_mean), tumor glycolytic activity, metabolic tumor volume (MTV), and metabolic intratumoral heterogeneity index (calculated as the AUC for the cumulative standardized uptake value [SUV]-volume histogram [CSH] index) were obtained. Information on patient demographic characteristics and tumor staging were collected. Median follow-up was 27.5 months. Overall survival (OS) and progression-free survival (PFS) were calculated using a multivariate Cox proportional hazards regression model and log-rank (Mantel-Cox) test to generate Kaplan-Meier survival plots. Results. The mean (± SD) age of the patients was 54.4 ± 13.1 years. Twenty-two patients had stage I disease; 58, stage II; 23, stage III; and 17, stage IV. Thirty-three patients died, 82 were living, and five were lost to follow-up and were censored; 29 patients had disease progression. The median survival was 74.9 months (95% CI, 63.6-86.9 months). A higher MTV was significantly associated with reduced OS in multivariate analysis (hazard ratio, 1.085; 95% CI, 1.036-1.136; p = 0.0005). A higher AUC-CSH index (denoting lower tumor heterogeneity) was significantly associated with increased OS (hazard ratio, 0.662; 95% CI, 0.448-0.979; p = 0.04) and PFS (hazard ratio, 0.683; 95% CI, 0.471-0.991; p = 0.045) in multivariate analysis. Kaplan-Meier survival analysis using the median value for MTV (61 mL) significantly predicted OS (p = 0.0009). Conclusion. Tumor heterogeneity on pretreatment PET/CT is associated with OS and PFS in patients with cervical cancer. MTV is significantly associated with OS.