title: A lack of significantly increased incidence of regression in second primary melanomas does not support an 'immunization effect'.
abstract: 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.
authors: Department of Dermatology, Rambam Medical Center, Rehov H'Aliya, Bat Galim, Haifa, Israel.
authors: Lilach
authors: L
authors: Zoller
authors: Elisa
authors: E
authors: Mayer
authors: Ofer Ben
authors: OB
authors: Itzhak
authors: Reuven
authors: R
authors: Bergman
mesh_terms: 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*