Is ulceration in cutaneous melanoma just a prognostic and predictive factor or is ulcerated melanoma a distinct biologic entity?
Ulceration of a primary cutaneous melanoma has for many years been recognized as a very important prognostic factor associated with increased risk for recurrence and mortality. Patients with an ulcerated melanoma do much worse than patients with a nonulcerated melanoma with the same breslow thickness. Ulceration may indicate a separate biologic entity. Gene profiling studies of fresh frozen melanoma samples indicated that ulcerated melanomas have a very different profile. Analysis of the results of the two largest adjuvant interferon (IFN) trials ever conducted in 2644 patients [European Organization for Research and Treatment of Cancer (EORTC) 18952 and 18991], which used ulceration of the primary as a stratification factor, indicated that ulceration was not only a very strong prognostic factor, but more importantly a significant predictive factor for outcome of adjuvant IFN treatment. Only in patients with an ulcerated primary, was a similar and significant impact on disease-free survival, distant metastasis-free survival and overall survival observed. As a more general finding, in trials independent of ulceration used as a stratification factor, this IFN sensitivity of ulcerated melanomas has been reported in a meta-analysis in more than 3000 patients. It was also identified as a predictive factor of outcome in the Sunbelt adjuvant IFN trial in the USA. These important findings regarding ulceration need biologic studies to identify the differences between ulcerated and nonulcerated melanoma at the molecular level. Moreover, the importance of ulceration will be assessed prospectively in the EORTC 18081 trial in patients with primary ulcerated melanomas more than 1 mm.