420 Melanoma in pregnancy in California, 1994-2015: A population-based study

Abstract

Melanoma is the most common malignancy during pregnancy. There is continued debate regarding the impact of pregnancy on the prognosis of melanoma. Prior studies have shown mixed results and the number of recent large population-based studies are limited, especially from the United States. To address this question, we used the California Cancer Registry data linked with Patient Discharge Data and Ambulatory Surgery Center Data to identify female patients, ages 15-44 years, diagnosed with melanoma in 1994-2015, including those who were pregnant. Women with pregnancy-associated melanoma (PAM) were compared with age-matched, non-pregnant women with melanoma. Multivariable logistic regression and multivariable cox proportional hazards regression models were used. We identified 13108 female patients diagnosed with melanoma, of which 1431 had PAM. PAM was associated with tumor site (more likely on lower than upper limb), tumor thickness (more likely in situ than invasive melanoma ≤1.0 mm), and histologic type (more likely superficial spreading than lentigo maligna). Lower overall survival was associated with non-Hispanic white race/ethnicity, lower neighborhood socioeconomic status, tumor site (head/neck, trunk or upper limb vs lower limb), greater tumor thickness, lymph node involvement, and more than 90 days to surgery (vs <30), but not pregnancy. In summary, we report a population-based analysis of melanoma in pregnancy in California. Although there were no differences in overall survival, pregnancy status was associated with tumor site, thickness, and histologic type, suggesting possible biological differences. Future studies are required to better understand the biological and molecular characteristics of melanoma in pregnancy.