Tailoring treatment strategy for stage IV colorectal cancer: assessing the impact of lung metastasis on multi-organ management

Background Resection of distant metastatic foci can improve the survival for stage IV colorectal cancer (CRC). However, surgical strategy for multiple organ metastases (MOM) is complicated and chemotherapy is often prioritized over surgical resection. This study analyzed the clinicopathological features of stage IV CRC with MOM to identify strategies for improving prognosis. Methods Among 281 stage IV CRC patients who were treated at our hospital from 2008 to 2022, 89 patients with MOM were included. Results The number of metastatic organs was 2 in 60 (67%) patients and 3 or more in 29 (33%). The most common metastatic site was liver (n=76, 85%), followed by lung (n=54, 61%), peritoneum (n=37, 42%), distant lymph node (n=31, 35%). Thirteen (15%) patients underwent curative-intended resection during the median follow-up of 52.8 months. Overall survival for patients with lung metastasis had significantly better than that for patients without (median 2.23 vs. 1.37 years, P = 0.007). In 49 patients with both liver and lung metastases, the overall survival rates at 3 years were 100% in 8 patients who underwent resections of the both and 64.8% in 9 patients who underwent resection of liver alone, which was significantly higher than 5.1% in 32 patients who received chemotherapy alone (P < 0.001 and P = 0.001, respectively). Conclusion In patients with MOM, lung metastasis was associated with a favorable survival probability even when being left in situ. This finding suggests that survival benefit of aggressive resection would depend on the metastatic site.