Prognostic factors in pulmonary metastasectomy and efficacy of repeat pulmonary metastasectomy from colorectal cancer

BACKGROUND: The rate of pulmonary metastasectomy from colorectal cancer (CRC) has increased with recent advances in chemotherapy, diagnostic techniques, and surgical procedures. The purpose of this study was to investigate the prognostic factors for response to pulmonary metastasectomy and the efficacy of repeat pulmonary metastasectomy. METHODS: This study was a retrospective, single-institution study of 126 CRC patients who underwent pulmonary metastasectomy between 2000 and 2019 at the Gifu University Hospital. RESULTS: The 3- and 5-year survival rates were 84.9% and 60.8%, respectively. Among the 126 patients, 26 (20.6%) underwent a second pulmonary metastasectomy for pulmonary recurrence after initial pulmonary metastasectomy. Univariate analysis of survival identified seven significant factors: (1) gender (p = 0.04), (2) past history of extra-thoracic metastasis (p = 0.04), (3) maximum tumor size (p = 0.002), (4) mediastinal lymph node metastasis (p = 0.02), (5) preoperative carcinoembryonic antigen (CEA) level (p = 0.01), (6) preoperative carbohydrate antigen 19-9 (CA19-9) level (p = 0.03), and (7) repeat pulmonary metastasectomy for pulmonary recurrence (p < 0.001). On multivariate analysis, only mediastinal lymph node metastasis (p = 0.02, risk ratio 8.206, 95% confidence interval (CI) 1.566–34.962) and repeat pulmonary metastasectomy for pulmonary recurrence (p < 0.001, risk ratio 0.054, 95% CI 0.010–0.202) were significant. Furthermore, in the evaluation of surgical outcomes, the safety of second pulmonary metastasectomy was almost the same as that of initial pulmonary metastasectomy. CONCLUSIONS: Repeat pulmonary metastasectomy is likely to be safe and effective for recurrent cases that meet the surgical criteria. However, mediastinal lymph node metastasis was a significant independent prognostic factor for worse overall survival.