title: Metastatic melanomas of unknown primary show better prognosis than those of known primary: a systematic review and meta-analysis of observational studies.
abstract: BACKGROUND
  Melanoma of unknown primary (MUP) is a condition of metastatic melanoma without a primary lesion.
  
  
  OBJECTIVE
  We sought to identify the prognosis of MUP compared with melanoma of known primary (MKP).
  
  
  METHODS
  We searched for observational studies containing at least 10 patients with MUP from MEDLINE and EMBASE from inception to December 22, 2012. The outcomes of interest were overall and disease-free survival; meta-analyses of hazard ratio stratified by stage using a random effects model were performed. In addition, second systematic review identified risk factors influencing the survival of patients with MUP.
  
  
  RESULTS
  Eighteen studies including 2084 patients with MUP and 5894 with MKP were included. MUP had a better overall survival compared with MKP in stage III (15 studies; hazard ratio 0.83, 95% confidence interval 0.73-0.96, P = .010) and stage IV (6 studies; hazard ratio 0.85, 95% confidence interval 0.75-0.96, P = .008). Secondly, 22 studies including 3312 patients with MUP were reviewed, and increased stage and old age were the risk factors in patients with MUP.
  
  
  CONCLUSIONS
  Diverse observational studies were reviewed, and selection and reporting biases are possible.
  
  
  CONCLUSIONS
  The current meta-analyses suggest better survival outcomes in patients with MUP than those in patients with MKP with the same corresponding tumor stage.
authors.affiliation: Department of Dermatology, St Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea; Department of Dermatology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Bae
authors.affiliation: Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yoon Young
authors.initials: YY
authors.lastname: Choi
authors.affiliation: Department of Dermatology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dae Suk
authors.initials: DS
authors.lastname: Kim
authors.affiliation: Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea; Department of Dermatology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hong Sun
authors.initials: HS
authors.lastname: Jang
authors.affiliation: Department of Dermatology, St Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Joo Hee
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea; Department of Dermatology, International St Mary's Hospital, Catholic Kwandong University College of Medicine, Seoul, Korea.
authors.forename: Heesu
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Dermatology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Byung Ho
authors.initials: BH
authors.lastname: Oh
authors.affiliation: Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea; Department of Dermatology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Mi Ryung
authors.initials: MR
authors.lastname: Roh
authors.affiliation: Department of Dermatology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyoung Ae
authors.initials: KA
authors.lastname: Nam
authors.affiliation: Department of Dermatology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea; Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea. Electronic address: kychung@yuhs.ac.
authors.forename: Kee Yang
authors.initials: KY
authors.lastname: Chung
mesh_terms: D006801:Humans; D008545:Melanoma / Q000401:mortality* / Q000556:secondary*; D009382:Neoplasms, Unknown Primary / Q000401:mortality*; D064887:Observational Studies as Topic; D011379:Prognosis; D012307:Risk Factors; D012878:Skin Neoplasms / Q000401:mortality* / Q000473:pathology*; D015996:Survival Rate
keywords: malignant melanoma; melanoma; melanoma, unknown primary; meta-analysis; prognosis; systematic review