title: Patients with cancer of unknown primary: a retrospective analysis of 223 patients with adenocarcinoma or undifferentiated carcinoma.
abstract: BACKGROUND
  Cancer of unknown primary (CUP) now accounts for 2-3% of all fatal cases of cancer in Germany. Histologically, most of these tumors are either adenocarcinoma or undifferentiated carcinoma. Scant data on their clinical features and prognosis are now available, and the published survival times are highly variable. In this article, we document and analyze our own experience with CUP to date.
  
  
  METHODS
  We took all 223 patients with CUP (adenocarcinoma or undifferentiated carcinoma) whom we saw in our CUP clinic from 2006 to 2010 as an unaltered sample for retrospective analysis of clinical data and overall survival. We performed the analysis with Kaplan-Meier plotting, log-rank testing, and Cox regression.
  
  
  RESULTS
  With a median follow-up time of 32.9 months, the median survival from the time of diagnosis was 16.5 months. Metastases were most commonly found in the lymph nodes, followed by the liver, bones, and lungs. The main pre-treatment prognostic variables that remained significant after adjustment for multiple testing were the Eastern Cooperative Oncology Group (ECOG) score for overall state of health and the number of organ systems involved. These variables were used to construct a practice-oriented risk stratification.
  
  
  CONCLUSIONS
  In patients with adeno- or undifferentiated CUP syndrome, the ECOG score and the number of organ systems involved are important risk factors.
authors.affiliation: Department of Internal Medicine V: Hematology, Oncology and Rheumatology, Heidelberg University Hospital.
authors.forename: Harald
authors.initials: H
authors.lastname: Löffler
authors.affiliation: Department of Internal Medicine V: Hematology, Oncology and Rheumatology, Heidelberg University Hospital.
authors.forename: Joe
authors.initials: J
authors.lastname: Puthenparambil
authors.affiliation: German Cancer Research Center, Department of Biostatistics, Heidelberg.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hielscher
authors.affiliation: Medical Clinic 2, Baden-Baden City Hospital, Klinikum Mittelbaden, Baden-Baden.
authors.forename: Kai
authors.initials: K
authors.lastname: Neben
authors.affiliation: Department of Internal Medicine V: Hematology, Oncology and Rheumatology, Heidelberg University Hospital.
authors.forename: Alwin
authors.initials: A
authors.lastname: Krämer
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000556:secondary*; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000401:mortality*; D015995:Prevalence; D016016:Proportional Hazards Models; D012307:Risk Factors; D017678:Sex Distribution; D015996:Survival Rate