Treatment for patients with unknown primary carcinoma and unfavorable prognostic factors.

The treatment for patients with unknown primary carcinoma, particularly those with unfavorable prognosis factors, has changed in the last decade, and continues to evolve. Empiric chemotherapy trials reported since 2000 with the newer drugs have improved the overall survival compared to retrospective historical data and prospective clinical trials reported from 1967 to 2000. Long-term survival (1, 2, 3 years and beyond) has been documented for a small minority of patients by several recent clinical trials. The survival of patients with a number of other advanced adenocarcinomas of known primary sites (colon, rectum, lung, pancreas) has been improved by the use of chemotherapy alone or combined with targeted drugs (bevacizumab, erlotinib), and about 60% of the patients with unknown primary adenocarcinomas harbor occult lesions of the colon, rectum, lung, or pancreas. Many of these patients have benefited from the newer broad-spectrum chemotherapy regimens. Several of these regimens appear about the same and currently represent the treatment of choice for the majority of these patients. Improvements in diagnostic pathology and molecular characterization of these carcinomas are likely to soon help select more appropriate and tailored therapies for many of these patients.