Since ultraviolet light exposure figures in the pathogenesis of both of these serious skin cancers, one leading theory regarding the explanation for the left-sided predominance of Merkel cell carcinoma and melanoma involves increased driver-side UV exposure while operating motor vehicles. Dr. Kluger finds this explanation unlikely. Although steering wheels are placed on the left side of vehicles in Finland, as in the United States, left-side predominance of these skin cancers also has been reported in countries such as Scotland, where drivers stick to the left side of the road and the steering wheel is on the right, he noted.
In Finland, there was a significant excess of Merkel cell carcinomas on the left side in nearly every year of the 20-year study. That means if the skewed lateral distribution of the tumors is due to some as-yet-unidentified environmental factor, it’s a factor that hasn’t changed in 20 years, Dr. Kluger observed.
"For now it’s an interesting curiosity," he commented.
Both Dr. Kluger and Dr. Samimi reported having no financial conflicts.