OBJECTIVETo explore the risk factors for pulmonary metastasis after curative resection of colorectal cancer in order to improve the effectiveness of follow-up and the rate of early diagnosis for the high-risk patients.

METHODSThe clinicopathological and follow-up data of 268 patients with colorectal cancer undergoing radical resection from January 2004 to December 2006 in the Beijing Cancer Hospital were analyzed retrospectively. Patients were divided into study group including 16(6.0%) patients who developed lung metastasis and control group without lung metastasis. The high-risk variables associated with lung metastasis were reviewed by univariate analysis and multivariate analysis.

RESULTSLung metastasis developed in 16 patients, including 10 cases with unilateral lung metastasis and 6 with bilateral. The median duration from colorectal surgery to identification of lung metastasis was 13.9 months. The diagnosis rate of pulmonary metastasis by enhanced chest CT was 81.3%(13/16). Univariate analysis identified the following associated with significant factors associated with pulmonary metastasis: primary tumor location(P=0.003), adjuvant chemotherapy(P=0.034), TNM stage(P=0.005) and preoperative serum carcinoembryonic antigen(CEA) level (P=0.001). Multivariate analysis revealed that primary tumor location(rectum) and preoperative serum CEA level(≥5 μg/L) were independent risk factors for pulmonary metastasis(both P<0.05).

CONCLUSIONSPrimary tumor location and elevated preoperative CEA level are independent risk factors for pulmonary metastasis. Strict postoperative follow-up and routine chest enhanced CT examination is necessary for this particular patient population.