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.
Limitations 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.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF- 2013R1A2A2A04015894 ).
© 2014 American Academy of Dermatology, Inc.
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