Small bowel metastases in non-small cell lung cancer.

A case report of stage I adenocarcinoma of the lung in a 43-year-old female with recurrence in the small bowel and liver 11 months after pneumonectomy is presented. In addition, a cohort of 733 patients with non-small cell lung cancer (NSCLC) in all pretreatment stages (stages I-IV) with a total of 218 autopsies are evaluated, and the literature on the topic is reviewed, in order to define the frequency of metastases from NSCLC to the small bowel. There were 10 cases with and 208 cases without small bowel involvement among 218 consecutive autopsies (autopsy rate, 30%,). The frequency of small bowel involvement was 4.6% (95%, confidence interval, 2.2-8.3%), and all were in patients with adenocarcinoma of the lung. All patients with small bowel involvement at autopsy had also other concurrent metastatic sites as well and the following were the most frequent: adrenals (90%, of cases), mediastinal lymph nodes (80%), liver (70%), pleura (60%), contralateral lung (60%), bones (60%), and brain (50%). Significantly more metastatic sites were observed in patients with than without small bowel involvement, both totally (P = 0.0001) and with respect to number of extrathoracic (P = 0.0001) and intrathoracic (P = 0.01) metastatic sites. In conclusion, small bowel involvement in NSCLC is relatively infrequent. As a unique finding, over-representation of patients with poorly differentiated tumors (P = 0.03) and patients having solid carcinoma with mucus formation after histologic subtyping (P = 0.04) among cases with small bowel involvement was observed. This indicates, that small bowel metastases is an epiphenomonen of NSCLC tumors with certain biological characteristics, although as yet undiscovered, which leads to a high metastatic potential. If such biological characteristics could be identified, they may be used in the selection of treatment options for individual patients, e.g. indicating a need for adjuvant or neoadjuvant chemotherapy in addition to surgery in resectable or marginally resectable NCSLC patients.