Number of primary melanomas is an independent predictor of survival in patients with metastatic melanoma.
BACKGROUND
A history of multiple primary melanomas (PMs) has been associated with improved survival in patients with early stage melanoma, but whether it also is correlated with survival in patients with metastatic melanoma is unknown. The authors sought to address the latter question in the current study.


METHODS
Patients with metastatic melanoma diagnosed at the Melanoma Institute Australia between 1983 and 2008 were identified. Overall survival (OS) was calculated from date of first distant metastasis. Survival analysis was performed using the Kaplan-Meier method, log-rank tests, and multivariate Cox proportional hazards models.


RESULTS
Of 2942 patients with metastatic melanoma, 2634 (89.5%) had 1 PM and 308 (10.5%) had >1 PM. Factors that were associated independently with shorter OS were site of metastasis, including the brain (hazard ratio [HR], 2.41; 95% confidence interval [CI], 2.07-2.81; P < .001) and non lung viscera (HR, 1.92; 95% CI, 1.67-2.22; P < .001, vs lymph node/subcutaneous/soft tissue), age >60 years (HR, 1.23; 95% CI, 1.12-1.36; P < .001), shorter disease-free interval from PM to first distant metastasis (≤ 12 months vs >36 months: HR, 1.62; 95% CI, 1.39-1.89; P < .001), and fewer PMs (1 vs >1; HR, 1.26; 95% CI, 1.08-1.47; P = .004).


CONCLUSIONS
A history of multiple PM was an independent predictor of improved survival for patients with metastatic melanoma. The results indicate that a history of multiple PMs should be incorporated into multivariate analyses of prognostic factors and treatment outcomes.
Melanoma Institute Australia, Sydney, New South Wales, Australia. muralir@mskcc.org
Rajmohan
R
Murali
Philip T
PT
Brown
Richard F
RF
Kefford
Richard A
RA
Scolyer
John F
JF
Thompson
Michael B
MB
Atkins
Georgina V
GV
Long
D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000401:mortality*; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009378:Neoplasms, Multiple Primary; D011379:Prognosis; D012878:Skin Neoplasms / Q000401:mortality*