Comparison of uptake characteristics and prognostic value of 201Tl and 18F-FDG in esophageal cancer.

BACKGROUND

Patients with esophageal cancer often undergo (201)Tl myocardial imaging for preoperative risk evaluation, thereby providing an excellent opportunity to assess tumor handling of (201)Tl. We thus compared the characteristics of (201)Tl and (18)F-FDG uptake by esophageal cancer and further investigated their prognostic values.

METHODS

The study included 100 newly diagnosed esophageal cancer patients who underwent preoperative (201)Tl SPECT and (18)F-FDG PET exams. Tumor to mediastinal uptake (T/M) ratio and retention index (RI) of (201)Tl, tumor (18)F-FDG pSUV, tumor size, location, and stage were assessed. Survival analysis was performed for disease-free survival using the Kaplan-Meier method. Cox proportional hazard models were used to determine independent risk factors.

RESULTS

(201)Tl SPECT and (18)F-FDG PET visualized the primary tumor in 85/100 (85.0%) and 91/100 (91.0%) patients, respectively (p = 0.03). There were close correlations between early and delayed (201)Tl T/M ratios (r = 0.83, p < 0.0001) and between T/M ratios and (18)F-FDG pSUV (r = 0.56 and 0.57, respectively, both p < 0.0001). Both T/M ratios and (18)F-FDG pSUV correlated significantly with tumor stage (rho = 0.45, 0.40, and 0.59, respectively, all p < 0.0001). Survival analysis revealed tumor size, (201)Tl negative tumors, (18)F-FDG negative tumors, delayed (201)Tl T/M ratio, RI, stage, and (18)F-FDG pSUV to be significant univariate predictors for disease-free survival. Multivariate survival analysis showed stage (p = 0.02) to be a significant independent prognostic predictor.

CONCLUSIONS

In patients with esophageal cancer, assessment of tumor (201)Tl uptake, as with (18)F-FDG, may provide potentially useful information regarding tumor characteristics.