Unknown primary tumors metastatic to liver.

PURPOSE

The objectives of this study were to identify prognostic factors for unknown primary tumor (UPT) patients with hepatic metastases, determine the common primary tumors identified, assess the yield of specific diagnostic studies, and evaluate the impact of therapy on survival.

PATIENTS AND METHODS

The 1,522 patients analyzed were referred from January 1, 1987 through June 30, 1995. Clinical data from these patients were entered into a computerized database for storage, retrieval, and analysis. Survival was measured from the time of diagnosis; survival distribution was estimated by the product limit method. Multivariate survival analyses were performed by proportional hazards regression.

RESULTS

Five hundred UPT patients had liver metastases. Primary tumors, usually lung, colorectal, or pancreatic neoplasms, were identified in 135 patients (27%). The remaining 365 unknown primary carcinoma (UPC) patients with liver involvement had a higher death rate than those without liver involvement (hazards ratio, 1.63; P < .0001). Neuroendocrine carcinoma patients had a lower death rate than patients without this histology (hazards ratio, 0.29; (P < .0001). Two hundred sixteen of 365 patients with UPC and liver metastases received chemotherapy. Chemotherapy-treated patients had a lower death rate than those who were not treated with chemotherapy (hazards ratio, 0.52; P < .0001). The effect of chemotherapy was most pronounced in patients with adenocarcinoma.

CONCLUSION

Hepatic metastases in UPC patients portend a generally poor prognosis. However, subsets of patients with more favorable outcomes can be identified by available clinical and pathologic data. Chemotherapy may be beneficial for the large subset of UPC patients with adenocarcinoma that involves the liver.