Outcomes of resected colorectal cancer lung metastases in routine clinical practice: a population-based study

Background — Previous reports on the outcome of surgery for colorectal cancer lung metastases (CRCLM) have come from high-volume centers. This report describes the outcomes achieved in the general population of Ontario.

Methods — All patients in Ontario who underwent resection of CRCLM between 1994 and 2009 were identified using the population-based Ontario Cancer Registry. Electronic treatment records identified surgical procedures and chemotherapy delivery. This report describes the volume of resections for CRCLM in relation to the incidence of colorectal cancer (CRC). Temporal trends in practice are described during three periods: 1994-1999, 2000-2004, and 2005-2009. Overall survival (OS) and cancer-specific survival (CSS) were measured from the time of lung resection.

Results — A total of 709 patients underwent resection of CRCLM. Between 1994 and 2009, surgical volume increased 190%, from 1 resection for every 282 incident cases to 1 resection for every 97 incident cases (p < 0.001). The use surgery for CRCLM varied considerably between regions, from 1 resection per 95 incident cases to 1 resection per 212 incident cases (p = 0.021). Use of perioperative chemotherapy increased during study periods, from 22% (28/130) to 34% (73/217) to 40% (146/362; p < 0.001). Utilization rates varied across geographic regions (range 21-59%; p = 0.005). The OS rate was 40% [95% confidence interval (CI) 36-44%] at 5 years and 27% (95% CI 23-31%) at 10 years. The CSS rate was 42% (95% CI 38-46%) at 5 years and 32% (95% CI 27-37%) at 10 years.

Conclusions — A proportion of patients with resected CRCLM will achieve long-term survival. Outcomes in routine practice are comparable with those reported for high-volume centers. The use of surgery varies considerably across Ontario.