Clinical and Radiological Discrimination of Solitary Pulmonary Lesions in Colorectal Cancer Patients

Abstract

The lung is one of the most common organs of metastasis from colorectal cancer (CRC), and we have encountered lung cancer patients with a history of CRC. There have been few studies regarding methods used to discriminate between primary lung cancer (PLC) and pulmonary metastasis from CRC (PM-CRC) based only on preoperative findings. We retrospectively investigated predictive factors discriminating between these lesions in patients with a history of CRC. Between 2006 and 2015, 117 patients with a history of CRC (44 patients with 47 PLC and 73 patients with 102 PM-CRC) underwent subsequent or concurrent resection of pulmonary lesions. We compared the clinical and radiological characteristics of 100 patients with solitary lesions (43 PLC and 57 PM-CRC). Using univariate and multivariate analyses, we examined predictive factors for discrimination of these two lesions. All tumors with findings of ground-glass opacity (GGO) were PLC (n=19). In a multivariate analysis of 81 radiologically solid tumors, two factors were found to be significant independent predictors of PLC: a history of stage I CRC and presence of pleural indentation. All tumors in 26 patients with either GGO or both a stage I CRC history and pleural indentation were PLC, while most tumors in patients without all three factors were PM-CRC (43/44; 97.7%). The presence or absence of GGO, pathological CRC stage, and pleural indentation could be useful factors to distinguish between PLC and PM-CRC.