Background: Cancer of unknown primary (CUP) origin is a very aggressive disease with a poor prognosis. Most of the literature reports of CUP are generated from tertiary cancer centers.
Methods: A retrospective chart review of all patients with a diagnosis of CUP was performed between January 1995 and January 2005. Age, gender, diagnostic evaluation, histologic diagnosis, location of metastases, treatment, and survival were recorded.
Results: Ninety-one patients met the inclusion criteria. The pathologic diagnoses included adenocarcinoma (42.8%), undifferentiated carcinoma (34.5%), squamous cell carcinoma (9.8%), neuroendocrine cancer (6.5%), sarcoma (3.2%), and nonspecific malignant neoplasm (3.2%). The overall mean survival was 9.2 months (95% confidence interval, 6.1-12.4 mo), and for squamous cell carcinoma was 26.9 months (standard error, 5.7; P = .007).
Conclusions: CUP encompasses a variety of different pathologic entities with an overall dismal 5-year survival. Nonetheless, squamous cell and neuroendocrine CUP are associated with a significantly better early prognosis than the other malignancies.