INCREASED THICKNESS OF PREGNANCY-ASSOCIATED MELANOMA

The effects of pregnancy on the pathophysiology of melanoma remain unc lear, Although a gender-specific advantage for women vs. men is seen f or characteristics such as stage at presentation, site of primary tumo ur, and survival time, an adverse effect of pregnancy on melanoma deve lopment and progression has been reported. In a retrospective study, w e investigated the tumour characteristics of women who developed pregn ancy-associated melanoma, and compared them with melanomas arising in non-pregnant women of child-bearing age. The patient records of the Ma ssachusetts General Hospital Pigmented Lesion Clinic were reviewed, an d 465 women of reproductive age (16-45 years) who developed melanoma w ere identified. Of these, in 45 women (age 21-42 years) there was a cl ose temporal relationship between diagnosis of the tumour and pregnanc y. Clinical and histological characteristics of the primary tumours we re recorded. Differences in tumour thickness, site and histological ty pe were analysed. The mean thickness of pregnancy-associated melanomas was significantly greater than that of non-pregnancy-associated tumou rs (2.28 vs, 1.22 mm, respectively; P < 0.007). No differences in hist ological type (P = 0.64) or site (P = 0.74) of the primary tumours wer e found between the two patient groups. Not surprisingly, multivariate analysis revealed that tumour thickness was a statistically significa nt variable in determining prognosis (P = 0.001). An unexpected findin g, on multivariate analysis, was a possible pregnancy-associated progn ostic advantage (P = 0.08). Melanomas arising during pregnancy are thi cker, but are not necessarily associated with a less favourable progno sis than tumours arising in non-pregnant women of child-bearing age. T he mechanisms by which pregnancy may lead to increased thickness of me lanoma have yet to be elucidated, and merit further study.