Abstract
565 Background: Resection of liver metastases is now accepted as a potentially curative strategy in some pts with mCRC. Resection of lung metastases (LMs) may also be beneficial but this is not well established. We hypothesized that resection of LMs may lead to prolonged survival in highly selected pts with mCRC. Methods: In this IRB-approved retrospective cohort study, cases were defined as mCRC pts with LMs as their only site of disease who underwent metastatectomy. Controls consisted of mCRC pts who had LMs but did not undergo resection. Charts were reviewed for clinical characteristics; survival data was obtained from the institutional tumor registry. The primary endpoint was overall survival (OS) in the cases versus controls. The secondary endpoint was to determine prognostic factors associated with better survival. Results: We included 26 consecutive cases of mCRC undergoing resection of LMs and randomly selected 26 controls. All pts in the both groups were treated with contemporary chemotherapy, as well as bevacizumab and anti-EGFR monoclonals when appropriate. The median OS from the time of diagnosis with LMs was 29.8 months (95% CI 22.9-36.6) in the control group versus 56.6 months (95% CI 47.3-65.8) for the cases who underwent resection (log rank p=0.04). A number of baseline factors were significantly different between the cases and controls. The control group contained more pts with poorly differentiated tumors (p=0.016); had more pts with synchronous versus metachronous presentation of LM's (p=0.001); had more pts with multiple vs solitary LM's (p<0.001); and had more pts with bilateral vs unilateral LMs (p<0.001). The interval from initial diagnosis to the onset of LMs was significantly longer in the resection group vs controls (22.9 vs 2.9 months, p<0.001). Conclusions: In this retrospective study, pts with mCRC to the lung who were referred for resection were more likely to have well differentiated, solitary, unilateral tumors, with a long interval between the original diagnosis and the onset of LMs. Pts selected using these criteria may have a significant survival benefit from surgical resection of their LMs.
