To the Editor.—In their recent article on thin melanomas invasive to less than 0.76 mm (Archives 1983; 118:41-44), Paladugu and Yonemoto emphasized that the presence of histologic regression was a poor prognostic sign. In their series, five (45.5%) of 11 thin melanomas with regressive features metastasized. On the other hand, three (12%) of 25 thin melanomas without evidence of regression did so.
Paladugu and Yonemoto concentrated on the importance of regression as a prognostic indicator while failing to address the significance of the 12% (3/25) incidence of metastasis for melanomas that did not exhibit regression. Gromet et al1 found that two (2%) of 98 such melanomas metastasized within six years. Day et al,2 in the prospective New York University—Massachusetts General Hospital (Boston) study on melanoma, reported an eight-year survival rate of 99% for all patients with melanoma invasive to a depth of less than 0.85 mm. The