Metastatic adeno or XXXX from an unknown primary site--natural history and guidelines for identification of treatable subsets.

@entity1 @entity43 @entity263 @entity0 @entity706 @entity5 @entity843 @entity2 @entity189 @entity259 @entity420 @entity44
Two hundred and eighty-six @entity1 presenting with metastatic @entity420 or @entity189 whose primary site was not identified by clinical history, physical examination and chest radiograph have been studied. Median survival from presentation was 22 weeks. Factors independently predicting improved survival were lymph node presentations, good performance status and body weight loss of less than 10 per cent. In 88 (31 per cent) @entity1 the primary @entity5 site was subsequently identified, in 58 (20 per cent) during life. @entity2 was the most frequently identified primary @entity5 , and in only 32 (11 per cent) of the @entity1 was a 'treatable' primary @entity5 (i.e. germ cell, breast, ovarian, prostate, @entity259 or @entity706 ) identified. Among the treatable primary @entity5 were those in eight out of 16 female @entity1 presenting with axillary metastases who were subsequently shown to have primary @entity0 and four of 13 females presenting with @entity843 who were found to have primary @entity43 . @entity263 was confirmed in five out of 13 @entity1 with raised serum acid phosphatase. Of 22 @entity1 with elevated serum alphafoetoprotein (AFP) or beta- @entity1 chorionic gonadotrophin levels (beta HCG) 18 had some features of the 'atypical @entity44 '. Of the total of 32 @entity1 with treatable @entity5 types, 29 (90 per cent) were identified during life. Median survival for @entity1 with treatable @entity5 types identified during life was 104 weeks, compared with 22 weeks for the group as a whole. Retrospective immunocytochemical staining of the original biopsy showed that prostatic specific antigen and antibodies to beta HCG and AFP were diagnostically useful, but a series of organ site non-specific markers of histogenesis or cellular differentiation (carcinoembryonic antigen, secretory component for IgA, peanut lectin binding, epithelial membrane antigen and keratin) showed no significant correlations with identified primary sites, responsiveness to empirical chemotherapy or survival. Metastatic @entity189 or @entity420 from an unknown primary site represents 6.5 per cent of all referrals to the medical oncology unit, Royal Prince Alfred Hospital, Sydney. We offer guidelines for the rapid identification of the limited number of primary sites for which effective and specific forms of systemic treatment are available.
