Gastrointestinal metastasis of primary lung cancer: An analysis of 366 cases.

The gastrointestinal (GI) tract is not a common site of metastasis in primary lung cancer. The aim of the present study was to reveal the clinical and prognostic characteristics of gastrointestinal metastases of lung cancer (GMLC). Information on 366 cases of GMLC was collected and factors that affect severe GI complications were analyzed. Univariate and multivariate survival analyses were performed using the Cox proportional hazards model. Of the cases analyzed, the small intestine (59.6%) and colorectum (25.6%) were the two organs where lung cancer was most likely to metastasize in the GI tract. Squamous cell carcinoma (28.5%), adenocarcinoma (27.6%) and large cell carcinoma (20.9%) were the three most common histological types. However, compared with the histological distributions of primary lung cancer, patients with large cell carcinoma exhibited the highest elevated risk of GMLC [relative risk (RR), 4.07; P<0.001] and those with adenocarcinoma exhibited the lowest risk (RR, 0.58; P<0.001). Differences in organ involvement and in histological type led to varying GI complications. It was also indicated that chemotherapy was associated with a decreased risk of hemorrhage (P=0.006), but there was no reduction in the risk of hemorrhage associated with perforation and obstruction (P>0.05). The median overall survival time of GMLC patients was 2.8 months (range, 0-108 months). The survival analyses revealed that perforation and extra-GI metastasis were negative prognostic factors but abdominal surgery was identified a positive prognostic factor. In conclusion, the histological distribution of GMLC differed from that of primary lung cancer. Sufficient and careful patient evaluation, targeted surgeries and systemic therapies for specific patients are able to increase patient survival rate and improve the quality of life.