We were interested to read the research letter by Bulliard et al1 published in the April 2008 issue of the Archives. Their observation of a left-sided excess of cutaneous melanoma in 5 regions of Switzerland is consistent with the results of our group's own study spanning 6 different countries, which was published in the European Journal of Cancer last year.2 Like Bulliard et al, we did not appreciate that the laterality of melanoma had been studied before, but after our study results were published, we became aware of a previously published study, based on US Surveillance Epidemiology and End Results (SEER) data (1973-1987), concluding that no substantial or consistent laterality bias existed in melanoma.3 However, the results of our own study,2 including more recent US SEER data (1998-2003), combined with the findings of Bulliard et al,1 represent data from 7 countries and suggest that the consistent observation of a left-sided excess of cutaneous melanoma is unlikely to be a chance finding. Analysis of more recent US SEER white population data4 (covering the years of incidence 2004-20055) reveals a persistently elevated overall left to right ratio of 1.09 (95% confidence interval, 1.06-1.12).
Brewster DH, de Vries E. Left-Sided Excess in the Laterality of Cutaneous Melanoma. Arch Dermatol. 2008;144(9):1235. doi:10.1001/archderm.144.9.1235-a