A comparative study of proliferative activity and tumor stage of pregnancy-associated melanoma (PAM) and non-PAM in gestational age women.

BACKGROUND: The influence of pregnancy on the development, progression, and prognosis of melanoma is controversial. OBJECTIVE: We sought to compare clinical characteristics, histologic features, and proliferative activity in pregnancy-associated melanoma (PAM) and melanoma in nonpregnant women of reproductive age (non-PAM). METHODS: In this retrospective cohort study, we reviewed medical records and pathology reports from women given a diagnosis of melanoma between 2006 and 2015. We also examined tumor proliferation rates using mitotic count and 2 immunohistochemical markers of proliferation, phosphohistone H3 and Ki-67. RESULTS: In 50 PAM and 122 non-PAM cases, a diagnosis of melanoma in situ was associated with PAM. Among invasive melanomas, there was no difference in proliferative activity between groups. Pregnancy status was also not associated with age at diagnosis, tumor site, Breslow depth, Clark level, ulceration, or overall stage. LIMITATIONS: This was a retrospective study with a small sample size of mostly patients with early-stage melanoma. CONCLUSIONS: In our study of primarily early-stage melanoma, pregnancy did not have a significant impact on tumor proliferation. Particularly for patients given a diagnosis of stage I melanoma who are undergoing close surveillance, a history of PAM should not outweigh traditional factors, such as advanced maternal age, in planning future pregnancies.