Lung metastases in metastatic gastric cancer: pattern of lung metastases and clinical outcome

There are only limited data regarding pulmonary metastasis from gastric cancer. Therefore, we analyzed large series of gastric cancer with pulmonary metastasis and analyzed their clinical characteristics and treatment outcome to enhance perception of metastatic gastric cancer. Of 20,187 advanced gastric cancer patients treated between 1995 and 2007, 193 (0.96%) were identified to have pulmonary metastasis from gastric cancer. The pulmonary lesions were detected at chest computed tomography (CT) scan or plain chest X-ray and/or abdominal pelvic CT scan covering the lower part of the lungs, and were divided into three patterns: lymphangitic, hematogenous, and pleural. The most frequently observed pattern of lung metastasis was hematogenous metastasis (52.3%) followed by pleural (35.2%) and lymphangitic (26.4%). Patients who had hematogenous pulmonary metastasis were significantly associated with hepatic metastasis (p = 0.004) and male sex (p = 0.012). Patients with lymphangitic metastasis were significantly associated with concomitant bone (p = 0.010) and bone marrow (p = 0.029) metastasis. In case of pleural metastasis, it was positively correlated with gastrectomy history (p = 0.015) and the presence of peritoneal metastasis (p = 0.020). After a median follow-up duration of 87 (9-162) months, the median survival after diagnosis of pulmonary metastasis was 4 (0-67) months. The most frequently observed pattern of lung metastasis was hematogenous metastasis (52.3%) followed by pleural (35.2%) and lymphangitic (26.4%) in gastric cancer patients. Among gastric cancer patients with lung metastases, patients with pleural metastasis or lymphangitic metastasis had shorter survival with 1.5-2-fold increased risk of deaths.