Adenocarcinoma of unknown primary site. The Brooke Army Medical Center experience

A retrospective analysis of 56 tumor board records carrying the diagnosis of adenocarcinoma of unknown primary site (ACUPS) was completed. The cohort represents 1.7% of the registrations during the period from 1971-1981. The liver was the most common site from which a biopsy specimen was taken for diagnosis. The lung and pancreas were the most frequent proven primary sites. Eighteen cases went to autopsy. Primaries remained undetected in five (27%). Three of 37 patients treated with chemotherapy responded (8%). All cases to survive for longer than 24 months were well-differentiated adenocarcinomas (median survival, 6 months). The median survival of the entire cohort was 4 months. The survival difference between well-differentiated histology and less-differentiated histology was not significant (P = 0.076). The search for the primary includes investigation of the patients' signs and symptoms and limited screening tests. Treatment has not been proven to alter the natural history of ACUPS and must be weighed against toxicity.