Distant organ metastasis patterns in lung cancer patients with pancreatic metastasis – a cluster analysis

Introduction
Pancreatic metastasis of lung cancer is rare, but the narrowing or obstruction of the biliary tract from pancreatic metastases limits the choice of antitumour agents. Lung cancer patients with pancreatic metastasis often have metastasis of other organs. For these patients, however, no studies have been conducted to evaluate distant metastasis sites as metastasis patterns. This study aims to assess whether these patients have specific metastasis patterns at the time of diagnosis of lung cancer.

Material and methods
Data were collected from consecutive lung cancer patients with pancreatic metastasis between April 2012 and March 2022. Metastatic patterns were analysed using cluster analysis in patients with lung cancer.

Results
During the study period, 33 (2.0%) of 1659 patients were diagnosed as having pancreatic metastasis. Of the 33 patients, 28 (84.8%) were male. Eighteen, 14, and one patient had small cell lung cancer (SCLC), lung adenocarcinoma, and large cell neuroendocrine carcinoma, respectively. They were divided into 3 groups by cluster analysis. A statistically significant difference in metastasis frequency was confirmed among these 3 groups (χ² test, p = 0.001).

Conclusions
In lung cancer patients with pancreatic metastasis, knowledge of the metastatic patterns might be useful for clinical practice in the foreseeable future because it enables more efficient detection of metastatic disease through imaging, and more effective treatment at predicted metastatic sites.