Indeterminate Pulmonary Nodules in Resected Liver Metastases from Colorectal Cancer: A Comparison of Patient Outcomes

Hepatic metastasectomy remains the only potentially curative treatment for colorectal liver metastases (CRLM). Some of these patients develop indeterminate pulmonary nodules (IPNs). This study aimed to compare outcomes of patients with and without IPN undergoing resection of CRLM to ascertain whether their presence is clinically significant.

Cases and controls were identified from a prospectively maintained database of CRLM resections. Patients with staging radiology demonstrating IPNs were included as cases. Controls were matched to the cases by four primary factors: age, type of resection (primary or redo), clinical risk score (CRS) and chemotherapy.

The median disease-free survival (DFS) and overall survival (OS) for the cases were 7.0 months (95% CI 4.8-9.2) and 28.6 months (95% CI 21.2-36.0), respectively, and 12.0 months (95% CI 10.7-13.2) and 30.5 months (95% CI 19.4-41.6) for the controls. The 1-, 3- and 5-year survival rates were 92.7, 39.7 and 0.0% for the IPN group, and 92.4, 32.9 and 21.9% for those without. In total, 60.7% of IPN patients progressed to lung metastases, of which 39.3% underwent pulmonary resections. DFS was significantly shorter in the IPN group (p = 0.022), but OS was not significantly different (p = 0.421). The presence of IPN was independently associated with a shortened DFS (p = 0.027), as was a CRS of 3 or greater (p = 0.007).

This study suggests that IPN does not significantly affect OS, but may predict earlier disease recurrence. IPN presence alone should not preclude radical resection but could be used to prompt more careful post-operative surveillance to detect lung metastases at a potentially operable stage.