Evaluation of tumor extent by 18F-FDG-PET/CT in patients with squamous cell carcinoma of the esophagus: Correlation with pathologic specimen

Objectives Many patients with esophageal carcinoma receive radiation therapy and accurate evaluation of the primary tumor extent is crucial. Recently, many papers have shown that ¹⁸F-FDG-PET/CT played an important role in determining of the radiation field. The purpose of this study was to investigate whether the PET/CT image correctly evaluated the longitudinal length of primary tumor or not, in patients with esophageal carcinoma.

Methods Twenty-one patients with newly diagnosed esophageal squamous cell carcinoma who underwent preoperative PET/CT were enrolled in this study. All patients were received curative surgery after PET/CT. The longitudinal length of primary tumor on pathologic specimen, recorded as length(path), was compared with that on PET/CT image.On PET/CT image, we measured the longitudinal length of primary tumor in different three ways; visual interpretation, SUV2.5 and 40% of maximum SUV, recorded as length(vis), length(SUV2.5), and length(SUV40%), respectively.Regression analyses were performed by simple regression on pathologic specimen to PET/CT image.

Results In total 21 patients, the correlation efficient of length (path) with length (vis), length (SUV2.5) and length (SUV40%) were 0.73 ,0.45, and 0.07, respectively.

Conclusions The longitudinal length of primary esophageal tumor measured on PET/CT image was closely correlated to that on pathologic specimen. Our study indicates that PET/CT is the optimal method to estimate the length of primary esophageal tumor and measuring by visual evaluation on PET/CT image provides the closest estimation.