Indeterminate Pulmonary Nodules Represent Lung Metastases in a Significant Portion of Patients Undergoing Liver Resection for Malignancy

Despite detection on imaging before resection of hepatic malignancies, the natural history of indeterminate pulmonary nodules (IPN) is unknown. The objective of this study is to determine how often IPN detected on imaging before surgery for hepatic malignancies represent lung metastases. Demographics, comorbidities, tumor characteristics, and surgical treatments of patients with pre-operative IPN who underwent liver resection and/or radiofrequency ablation for malignant diagnoses were reviewed. From 2000 to 2010, 90 patients with at least one IPN underwent liver resection or radiofrequency ablation for malignancy. Of these, 44 (48.9 %), 32 (35.6 %), and 14 (15.6 %) patients had colorectal cancer liver metastases (CRCLM), primary hepatobiliary malignancies (HB), and other cancers, respectively. The median number of IPN was 1. The median size was 4 mm. Twenty (22 %) patients had isolated lung recurrence after hepatic surgical therapy. Eighty percent occurred in the exact location of the pre-operative IPN. Isolated lung recurrence was more common among patients with CRCLM compared to those with HB and other cancers (42.9 vs. 9.4 vs. 14.3 %, p = 0.004). Pre-operatively detected IPN represent lung metastases in a substantial portion of patients undergoing surgery for hepatic malignancy. IPN are more likely to represent lung metastases in patients with CRCLM compared to those with primary HB and other cancers.