Pregnancy-associated melanoma epidemiology: A multicentre European study

Melanoma is the most common malignancy during pregnancy, with incidence rates rising globally. While most studies focus on prognosis, limited data exist on melanoma in the early post-partum period.

This multicentre European study aimed to characterize the epidemiologic and clinicopathologic features of pregnancy-associated melanoma (PAM) and assess whether these tumours differ from melanomas not associated with pregnancy.

We identified 1,270 women of reproductive age (15-49 years) diagnosed with melanoma between 2012 and 2022 across six melanoma centres in five European countries.

Among them, 70 cases (5.5%) were classified as PAM (range: 1.2%-14.3%). Compared to non-PAM patients, women with PAM were younger (mean age 35.7 years; p < 0.001) and more likely to have a high nevus count (p = 0.031). The majority of PAMs (80.0%) were superficial spreading, and mean Breslow thickness was 1.16 mm; 12.9% were ulcerated. Notably, 57.1% developed on a pre-existing nevus. Histopathologic features were similar between groups, except for tumour-infiltrating lymphocytes (TILs): non-PAM tumours exhibited significantly more dense TILs (p = 0.012), possibly indicating a stronger immune response. Median follow-up was 5.5 years. Recurrence-free survival did not significantly differ between groups; the 5-year recurrence-free survival rate was 95%.

Although pregnancy does not appear to adversely impact melanoma prognosis, PAM demonstrates some distinct clinical features that warrant further investigation given the fact that it affects a substantial proportion of women of reproductive age diagnosed with melanoma. The frequent occurrence of PAM on pre-existing nevi highlights the importance of raising public awareness and promoting dermatologic evaluation of suspicious lesions during pregnancy.