Intratumoral Metabolic Heterogeneity and Other Quantitative 18F-FDG PET/CT Parameters for Prognosis Prediction in Esophageal Cancer

Abstract

Purpose: To evaluate the impact of intratumoral metabolic heterogeneity (IMH) and other quantitative fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT parameters for predicting progression-free survival (PFS) and overall survival (OS) in patients with esophageal cancer.

Materials and methods: In this retrospective study, an automated gradient-based segmentation method was used to assess the maximum standardized uptake value, mean standardized uptake value, metabolic tumor volume (MTV), and IMH index of the primary tumor in patients with biopsy-proven adenocarcinoma or squamous cell carcinoma of the esophagus with an initial staging ¹⁸F-FDG PET/CT. Data were collected between July 2006 and February 2016. OS and PFS were calculated using multivariable Cox proportional hazards regression with the adjustment (as covariates) of age, sex, weight, stage, tumor type, tumor grade, and treatment. All PET parameters were standardized before analysis. Log-rank tests were performed, and corresponding Kaplan-Meier survival plots were generated.

Results: A total of 71 patients (mean age, 64 years ± 10 [standard deviation], 62:9 men:women) were included. Median follow-up time was 28.2 months (range, 4-38 months), and median survival was 16.1 months (range, 0.1-60.3 months). Higher MTV was associated with reduced PFS for every standard deviation increase (hazard ratio [HR], 0.193; 95% CI: 0.052, 0.711; P = .01). Higher IMH was associated with reduced PFS for every standard deviation decrease in the area under the curve (HR, 10.78; 95% CI: 1.31, 88.96; P = .03).

Conclusion: PFS for patients with esophageal cancer was associated with MTV and with IMH.Keywords: Esophagus, Neoplasms-Primary, PET/CT, Tumor Response © RSNA, 2020.

Figure 1:

Progression-free survival curve based on median cutoff points for area under the curve of cumulative standardized uptake value volume histogram (P = .03). AUC-CSH = area under the curve of a cumulative standardized uptake-volume histogram.

Figure 2:

A, Axial ¹⁸F fluorodeoxyglucose (¹⁸F-FDG) PET/CT images in a 55-year-old man with stage III moderately differentiated adenocarcinoma (outlined in purple), with maximum standardized uptake value (SUVmax) of 9.54, metabolic tumor volume (MTV) of 19.12 mL, area under the curve of cumulative standardized uptake value volume histogram (AUC-CSH) of 6458, and a large area under the curve, corresponding to low IMH, B. This patient survived for 91 months after diagnosis. C, Axial ¹⁸F-FDG PET/CT images in an 80-year-old man with stage III moderately differentiated adenocarcinoma, with a higher SUVmax of 20.4 and slightly higher MTV of 22.45 mL (compared with the patient in A and B), D, but a lower AUC-CSH of 4805 (significantly smaller area under the curve), corresponding to high IMH. This patient survived for 60 months after diagnosis.