Melanoma thickness associated with decreased survival

Melanoma thickness has a progressive relationship with decreasing survival, however that relationship is lost in patients with melanomas 15 mm or thicker, according to a study.

“Most thick melanomas exceed 4 mm in thickness by just a few millimeters. However, little is known about the prognostic value of Breslow thickness in patients with melanomas greater than 8 mm,” Mary-Ann El Sharouni, MD, of the Melanoma Institute Australia at the University of Sydney, and colleagues wrote. “Our clinical impression has been that long-term survival occurs more often in patients with ‘ultra-thick’ melanomas (which we defined as 15 mm or greater) than in some patients with melanomas in the 4 mm to 8 mm range.”

A cohort study analyzed melanomas 4 mm and thicker in of 5,595 patients in the Netherlands and Australia.

Five-year overall survival was 52.9% for patients with melanomas between 4 mm and less than 10 mm (95% CI, 51.4-54.4), 35.9% for melanomas between 10 mm and less than 15 mm (95% CI, 31.2-41.3), 34.5% for 15 mm to less than 20 mm melanomas (95% CI, 25.9-46) and 47.9% for those 20 mm and thicker (95% CI, 37.3-61.6).

Five-year recurrence-free survival rates were s 38.2% (95% CI, 36.7-39.7), 25% (95% CI, 21-29.9), 19.3% (95% CI, 12.7-29.4) and 32% (95% CI, 22.8-45.1), respectively.

For both outcomes the continuous hazard ratio increased in patients with melanomas up to 15 mm, then stabilized up to 20 mm and decreased in those with melanomas greater than 20 mm.

“While increasing Breslow thickness is strongly associated with worse survival outcomes in patients with cutaneous melanoma, its progressive prognostic value is lost in patients with ‘ultra-thick’ melanomas (15 mm or greater in thickness),” the researchers wrote.