Size of metastatic deposits affects prognosis in patients undergoing pulmonary metastectomy for colorectal cancer

INTRODUCTION Pulmonary metastectomy for colorectal cancer (CRC) is a well accepted procedure although data regarding indications and prognostic outcomes are inconsistent. This study aimed to analyse our experience with resection of pulmonary CRC metastases to evaluate clinically relevant prognostic factors affecting survival. METHODS A retrospective analysis was undertaken of the records of all patients with pulmonary metastases from CRC who underwent a thoracotomy between 2004 and 2010 at a single surgical centre. RESULTS Sixty-six patients with pulmonary metastases from the colon (n=34) and the rectum (n=32) were identified. The 30-day hospital mortality rate was 0%, with 63 patients undergoing a R0 resection and 3 having a R1 resection. The median survival was 45 months and the cumulative 3-year survival rate was 61%. Size of pulmonary metastasis and ASA (American Society of Anesthesiologists) grade were statistically significant prognostic factors (p=0.047 and p=0.009 respectively) with lesions over 20mm associated with a worse prognosis. Sex, age, site, disease free interval (cut-off 36 months), primary tumour stage, hepatic metastases, number of metastases (solitary vs multiple), type of operation (wedge vs lobe resection), hilar lymph node involvement and administration of adjuvant chemotherapy were not found to be statistically significant prognostic factors. CONCLUSIONS Pulmonary metastectomy has a potential survival benefit for patients with metastatic CRC. Improved survival even in the presence of hepatic metastases or multiple pulmonary lesions justifies aggressive surgical management in carefully selected patients. In our cohort, size of metastatic deposit was a statistically significant poor prognostic factor.