Serial positron-emission tomography after induction therapy as a predictor of prognostic outcomes for patients with thymic carcinoma.

Purpose: To investigate the role of ¹⁸F-fluorodeoxy glucose-positron emission tomography/computed tomography (FDG-PET/CT) to assess pathological response and prognosis after induction therapy in patients with thymic carcinoma.

Methods: The subjects of this retrospective study were 18 patients with thymic carcinoma who underwent FDG-PET, before and after induction therapy. We measured the maximum standardized uptake value (SUVmax) of the tumor and analyzed the correlation between the change in SUVmax and pathological response or recurrence.

Results: Induction therapy led to a reduction in both the tumor size and SUVmax in most patients. A strong correlation (Pearson coefficient = 0.90, p < 0.0001) was observed between the changes in tumor size and SUVmax. Although the SUVmax and tumor size showed no association with the pathological response, an SUVmax change > 50% predicted lower recurrence rates (p = 0.03).

Conclusion: Changes in the SUVmax following induction therapy may serve as a valuable predictor of recurrence in patients with thymic carcinoma. This finding highlights the potential of FDG-PET as a tool for patient monitoring and prognostication of this rare subset of carcinomas. Further studies are warranted to validate these results and standardize the FDG-PET protocols for optimal clinical use.