Pulmonary metastases from pancreatic cancer have different clinico-radiological features compared with those from colorectal cancer.

[BACKGROUND] Although pulmonary metastasectomy is a commonly-performed procedure, data are lacking on the feasibility and oncological efficacy of removal of pulmonary metastases from pancreatic cancer. In this study, we retrospectively compared features of pulmonary metastases from pancreatic cancer versus colorectal cancer (CRC, patients with CRC being common candidates for pulmonary metastasectomy) and outcomes of removing such metastases, with our aim being to identify specific features of the former.

[METHODS] Data on removal of 182 pulmonary metastases (29 from pancreatic and 153 from CRC) performed from January 2013 to April 2024 were included in this analysis. Radio-pathological findings were compared between these groups. The study cohort comprised 139 pulmonary metastasectomies in 119 patients (24 with pancreatic cancer and 95 with CRC) in whom R0 resection was achieved and follow-up data were available.

[RESULTS] Atypical radiological findings of pulmonary metastases, including polygonal-shape (P < 0.001), spiculae (P < 0.001), air bronchogram (P = 0.012), peripheral ground-glass opacities (P < 0.001), and pleural tags (P < 0.001) were present more frequently in metastases from pancreatic cancer than from CRC. Furthermore, pleural lavage cytology was more frequently positive in pulmonary metastases from pancreatic cancer than in those from CRC (P < 0.001). Disease-free survival was significantly shorter after the removal of metastases from pancreatic than from CRC (P < 0.001).

[CONCLUSIONS] Some pulmonary metastases from pancreatic cancer have atypical radiological features. Surgical interventions for these may enable diagnosis. The prognosis is significantly poorer after removing metastases from pancreatic cancer than from CRC. The therapeutic significance of our findings requires further investigation.