title: Poorly differentiated carcinoma and poorly differentiated adenocarcinoma of unknown origin: favorable subsets of patients with unknown-primary carcinoma?
abstract: OBJECTIVE
  The objectives of this study were to assess clinical outcomes and prognostic factors in unselected, consecutive patients with poorly differentiated carcinoma (PDC) or poorly differentiated adenocarcinoma (PDA).
  
  
  METHODS
  The 1,400 patients analyzed were referred to our unknown-primary tumor (UPT) clinic from January 1, 1987 through July 31, 1994. Clinical data from these patients were entered into a computerized data base for storage, retrieval, and analysis. Survival was measured from the time of diagnosis; survival distribution was estimated using the product-limit method. Multivariate survival analyses were performed using proportional hazards regression and by recursive partitioning.
  
  
  RESULTS
  Nine hundred seventy-seven patients were diagnosed with unknown-primary carcinoma (UPC) and 337 of these patients had PDC or PDA. No clinical differences were identified among patients with PDC, PDA, or UPC patients with other carcinoma or adenocarcinoma subtypes. PDC patients enjoyed better survival than PDA patients. Poor cellular differentiation was not an important prognostic variable. Variables predictive of survival included lymph node metastases, sex, number of metastatic sites, histology (PDC v PDA), and age. Although chemotherapy did not appear to influence survival for the entire group of PDC or PDA patients, a subset of patients with good prognostic features experienced median survival durations of up to 40 months.
  
  
  CONCLUSIONS
  The long median survival and chemotherapy responsiveness of UPC patients with PDC and PDA could not be confirmed. However, subpopulations with prolonged median survival durations could be defined, and the value of chemotherapy in this group remains to be determined. Identification and exclusion of treatable or slow-growing malignancies may account for the poor survival of the PDC and PDA patients reported in this study.
authors.affiliation: Department of Clinical Investigation, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: R
authors.initials: R
authors.lastname: Lenzi
authors.forename: K R
authors.initials: KR
authors.lastname: Hess
authors.forename: M C
authors.initials: MC
authors.lastname: Abbruzzese
authors.forename: M N
authors.initials: MN
authors.lastname: Raber
authors.forename: N G
authors.initials: NG
authors.lastname: Ordoñez
authors.forename: J L
authors.initials: JL
authors.lastname: Abbruzzese
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology; D002277:Carcinoma / Q000097:blood / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009363:Neoplasm Proteins / Q000097:blood; D009382:Neoplasms, Unknown Primary / Q000097:blood / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology; D011379:Prognosis; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D009363:Neoplasm Proteins