Ringed fluorodeoxyglucose uptake predicted poor prognosis after resection of pulmonary pleomorphic carcinoma.

Background: Pulmonary pleomorphic carcinoma (PPC) is a relatively rare and poorly differentiated non-small cell carcinoma. This study aimed to investigate the clinicopathological features including programmed cell death ligand 1 (PD-L1) expression status in patients with PPC who underwent curative resection.

Methods: We retrospectively studied 29 consecutive patients who had undergone anatomical lung resections for PPC. Perioperative and pathological variables, including radiological findings, were investigated to define prognostic factors.

Results: Overall survival (OS) rates were 71.8% at 1 year and 60.0% at 5 years. Disease-free survival (DFS) rates were 54.8% at 1 year and 43.6% at 5 years. Univariate analysis revealed that ringed fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) (p = 0.003), a cavity in the tumor on CT (p = 0.004), and tumor size (> 40 mm) (p = 0.014) were poor prognostic factors for OS. Regarding DFS, ringed FDG uptake (p = 0.002), a cavity on CT (p < 0.001), tumor size (p = 0.007), and pleural invasion (p = 0.014) were poor prognostic factors. PD-L1 expression was not a prognostic factor.

Conclusion: This study showed for the first time that ringed FDG uptake on PET/CT is a poor prognostic factor of PPC. PD-L1 expression status was not related to the prognosis. Trial registration The study was approved by the Kobe City Medical Center General Hospital's ethics board (No. 20112) on August 20, 2020.