A lack of significantly increased incidence of regression in second primary melanomas does not support an 'immunization effect'.
OBJECTIVE
To compare the incidence of regression in first and second primary melanomas as a possible indication of an 'immunization effect'.


METHODS
The first and second primary melanomas of 18 patients were studied histopathologically for signs of regression. At least 1 month elapsed between the removal of the two primary lesions.


RESULTS
Histopathological evidence of regression was found in 7 of the 18 (38.8%) first melanomas and in 8 of the 18 (44.4%) second melanomas [p = non-significant (N.S.)]. Among the nine patients in whom the removal of the second primary melanoma was >6 months after the removal of the first primary melanoma, one (11%) first melanoma and three (33%) second melanomas showed regression, respectively, but this difference did not reach statistical significance. Among the nine patients in whom the removal of the second primary melanoma was ≤ 6 months after the removal of the first primary melanoma, six (67%) first melanoma and five (56%) second melanomas showed regression (p = N.S.).


CONCLUSIONS
Our study does not provide evidence for a statistically significant increased rate of regression in second primary melanomas compared to the first primary melanomas, but larger groups of studied cases may be needed.
Zoller
Lilach
L
Department of Dermatology, Rambam Medical Center, Rehov H'Aliya, Bat Galim, Haifa, Israel.
Mayer
Elisa
E
Itzhak
Ofer Ben
OB
Bergman
Reuven
R
D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D009365:Neoplasm Regression, Spontaneous / Q000473:pathology*; D009367:Neoplasm Staging; D016609:Neoplasms, Second Primary / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*