Incidence and predictive factors for pulmonary metastases after curative resection of colon cancer.

Purpose: To assess the actuarial incidence of pulmonary metastases as the first site of metastasis after R0 resection of colon cancer and to clarify predictive factors for pulmonary metastases as the first site of metastasis.

Methods: Data for 746 patients who underwent R0 resection for colon cancer from 2000 to 2006 were reviewed. The mean duration of follow-up was 56.9 months.

Results: Pulmonary metastases developed in 35 patients. Mean duration from colon surgery to identification of pulmonary metastases was 20.0 months. The overall occurrence rates of 5-year pulmonary metastasis according to Union for International Cancer Control (UICC) stage were 0.6 % (stage I), 2.2 % (stage II), 9.8 % (stage III), and 24.6 % (stage IV), respectively. Surgery for pulmonary metastases was performed first 18 patients (51.4 %), and 16 (88.9 %) of these 18 patients achieved R0 surgery. Multivariate analysis revealed that presence of regional lymph node involvement and preoperative serum carcinoembryonic antigen level (≥5 ng/ml) were significant independent risk factors for pulmonary metastases. Five-year actuarial incidence of pulmonary metastases increased significantly with increased number of risk factors (0 factors, 2.2 %; 1 factor, 6.6 %; 2 factors, 18.4 %).

Conclusions: The present study clearly demonstrated predictive factors for pulmonary metastases after R0 resection of colon cancer. Actuarial incidence of pulmonary metastases was significantly related to the number of risk factors present. The data should facilitate the establishment of novel algorithms for predicting pulmonary metastases after resection of colon cancer, which may lead to the appropriate surveillance strategies after colon surgery.