Small bowel metastases from primary carcinoma of the lung.

Although about half of all patients with carcinoma of the lung have metastases at initial presentation, only nine with metastases to the small bowel have been previously reported. This study was performed to determine the incidence of occult and clinically apparent metastases of lung cancer to the small intestine. Small bowel metastases were present in 46 of 431 patients with primary lung cancer who underwent autopsy during an 11-year period. These patients had an average of 4.8 metastatic sites. Small bowel metastases were present in 12 of 31 (39.0%) patients with large cell carcinoma, 13 of 108 (12.3%) with adenocarcinoma, six of 73 (8.0%) with small cell carcinoma, 15 of 199 (7.5%) with squamous cell carcinoma, and none of 20 with undifferentiated carcinoma. During the same interval, six of 78 patients undergoing small bowel resection for metastatic tumor had lung cancer primaries. Among the nine previously reported clinical cases of small bowel metastases and the six in this series, 14 were operated upon for small bowel perforation and one for obstruction. Nine patients died perioperatively, and no patient survived longer than 16 weeks. These data demonstrate that the incidence of lung cancer metastases to the small bowel is higher than is clinically apparent. Lung cancer metastases to the small bowel often present as intestinal perforation and indicate a poor prognosis; surgery is indicated for palliation.