Clinicopathological features and outcome of gastric metastases from primary lung cancer: A case report and systematic review.

Primary lung cancer is the fourth most frequently diagnosed cancer, but gastric metastasis from lung cancer is extremely rare. Little is known about its clinicopathological features, prognosis and optimal treatment strategy. The present study reports a case of primary lung cancer that metastasized to the stomach and to the best of our knowledge, is the first to identify discordance in epidermal growth factor receptor (EGFR) mutation status between the primary tumor and gastric metastasis. The study also systematically searched the Medline database for similar cases to provide a literature review. Data concerning the clinicopathological features, treatment strategies and outcomes were extracted and analyzed. In total, 22 eligible cases were identified from 16 studies. The average age at presentation was 67.3 years and there was a male predominance of 90.9%. Epigastric pain (45.5%) was the most common chief complaint, followed by melena (22.7%), nausea/vomiting (13.6%) and hematemesis (9.1%). Three patients were asymptomatic. Five patients sought the initial consultation for gastrointestinal symptoms. The median time between the primary lung cancer diagnosis and the confirmation of gastric metastasis was five months. Endoscopically, gastric lesions were described as polypoid masses or volcano-like ulcers, mostly involving the gastric corpus, which were identified in 62.5% of the 16 cases in which information regarding the site of metastasis was available. Gastric metastases were reported from adenocarcinoma, squamous cell carcinoma, small cell lung cancer and pleomorphic carcinoma of the lung. The median survival following comprehensive treatment strategies was four months, and the one-year post-metastasis survival rate was 35.3%. In conclusion, although primary lung cancer metastasis to the stomach is rare, clinicians should be aware of the possibility of its occurrence. Comprehensive and personalized treatment may be beneficial to patients. EGFR tyrosine-kinase inhibitor therapy may be the treatment of choice for non-small cell lung carcinoma patients harboring an activating EGFR mutation in the metastatic lesion.