Influence of lung metastases on outcomes of curative management of peritoneal metastases from colorectal cancer

Background: Traditionally there has been a nihilistic approach towards patients with pulmonary metastases arising from colorectal cancer. However, emerging evidence highlights the benefit of curative intent treatment. Given the established individual roles of pulmonary metastectomy and CRS/HIPEC in the treatment of colorectal pulmonary and peritoneal metastases, respectively, we decided to combine these modalities and determine whether pulmonary metastases really influence the outcomes of curative intent treatment in CRC patients with peritoneal metastases. Methods: This was a retrospective study of a prospectively maintained database of CRC patients with peritoneal metastases undergoing CRS and HIPEC with curative intent from Jan 1, 2005 to Aug 1, 2018. Patients were divided into two groups of without pulmonary metastases and with pulmonary metastases. Patients were followed up for a median 40.8 months. Results: Of total 455 patients 19 had pulmonary metastases. The median RFS and OS of all patients was 14.26 months (95 % CI:12.71-16.2) and 56.96 months (95 % CI: 47.73-77.79) respectively. Median RFS and OS of patients with and without pulmonary metastases was 12 & 49.8 months and 14.4 & 57.9 months, respectively. On multivariate analysis, PCI, CC-0 rate, CEA, signet ring histology and retroperitoneal lymph node metastases significantly affected the OS. Presence of pulmonary metastases did not significantly affect the RFS or OS. Conclusion: There has always been a skepticism in the management CRC with PM and extraperitoneal disease, especially pulmonary metastases with curative intent. Our study demonstrates that CRS and HIPEC improves OS in such patients and pulmonary metastases per se do not influence the outcomes of disease. Nevertheless, further prospective and multi centric studies are required to validate these findings.