Pulmonary Metastasectomy for Colorectal Cancer: Predictors of Survival in Routine Surgical Practice

Background. Resection of lung metastases is considered standard treatment for patients with metastatic colorectal cancer. We describe surgical management, prognostic factors, and outcomes in routine clinical practice. Methods. All cases of colorectal cancer lung metastases in Ontario, Canada, resected during 2002 to 2009 were identified using the Ontario Cancer Registry and linked electronic records. Pathology reports were reviewed to identify extent of disease. Results. The study population included 420 patients (60% male). Median age was 64 years. A solitary metastasis was present in 61% (256 of 420). Mean size of the largest metastasis was 2.4 cm. Lymph nodes were resected in 63% (263 of 420) of patients. The 5-year cancer-specific survival (CSS) and overall survival (OS) was 42% (95% confidence interval [CI], 37% to 47%) and 40% (95% CI, 35% to 45%), respectively. On adjusted analyses, greater number (p < 0.001) and size (p = 0.001) of lesions and lymph node involvement (p < 0.001) were associated with inferior CSS and OS. Lymph node positivity was strongly associated with survival (adjusted CSS hazard ratio, 2.19 [95% CI, 1.48 to 3.25]; adjusted OS hazard ratio, 2.08 [95% CI, 1.41 to 3.07]). Unadjusted 5-year CSS/OS was 49%/47% for node-negative disease and 19%/19% for node-positive disease. The negative prognostic effect of size (>-2 cm) and number (> 1) of lesions was additive: 5-year CSS/OS ranged from 57%/55% (single lesion < 2 cm) to 24%/20% (multiple lesions, largest lesion > 2 cm). Conclusions. Long-term survival of patients with resected colorectal cancer lung metastases in routine practice is comparable to outcomes reported in institutional case series. Lymph node positivity is strongly associated with reduced survival. Combining size and number of metastatic lesions in advance of the operation may facilitate treatment decision making. (C) 2018 by The Society of Thoracic Surgeons