Clinical characteristics and survival analysis in patients with isolated pulmonary metastases from colorectal cancer (CRC).

Abstract

60 Background: Recent studies seem to indicate that patients with metastatic colorectal cancer (mCRC) with exclusive pulmonary metastatic disease have better outcomes than those with other metastatic sites. The aim of this study is to identify differences in clinical and survival characteristics between the two groups in a cohort of a third level hospital. Methods: We retrospectively analyzed a sample of 569 patients with mCRC in a tumor registry from 2015 to 2021, studying clinical and molecular characteristics, as well as overall survival data of patients with isolated pulmonary metastases, versus the rest of patients. Results: Of the total sample analyzed, 61 patients (10.7%) had isolated pulmonary metastases. In these patients, several clinical characteristics were more frequent: primary rectal tumor (52.5% vs 23.4%, p < 0.000), resected primary tumor (95.1% vs 78.9%, p = 0.0026), metachronous metastatic disease (62.3% vs 42%, p = 0.0025) and complete response rate to the first line of treatment (19.3% vs 9.9%, p = 0.026). Furthermore, analytically, these patients were more likely to have normal CEA (75% vs 38.3%, p < 0.000), CA 19.9 (84.3% vs 57.7%, p = 0.0002) and LDH (91.1% vs 66.5%, p = 0.0007) levels. In our cohort, we found no statistically significant differences in tumor mutational status (KRAS, NRAS, BRAF, PI3K and HER2). There were no patients with exclusive pulmonary metastatic disease and microsatellite instability (MSI). 70.3% of patients with isolated pulmonary metastases received lung metastasectomy, and up to 58.3% received a second metastases surgery. We also found a numerical benefit in terms of overall survival (OS) in patients with exclusive metastatic lung disease, although it did not reach statistical signification (median OS 77.3 vs 58.1 months, HR for death 0.70, 95% CI, 0.49 – 1.01, p = 0.083). Conclusions: In our cohort, patients with isolated pulmonary metastases were more likely to have rectal tumors, primary tumor resection, metachronous metastatic disease, higher rate of complete responses and normal CEA, CA 19.9 and LDH levels, with a possible benefit in terms of OS.