18 | Surgical management of pregnancy-associated melanoma: a single institution experience with thirty-three pregnant patients

B. Taglione¹, I. Mattavelli¹, A. Maurichi¹, G. Gallino¹, D. Cortese¹, E. Tolomio¹, G. Spadola¹, C. Barbieri¹, S. Mercurio¹, B. Scoppio¹, B. Valeri², M. Cossa², M. Maccauro³, L. Di Guardo⁴, M. Del Vecchio⁴, M. Santinami¹, R. Patuzzo¹ | ¹IRCCS Istituto Nazionale Tumori Milano, Surgery, Milano; ²IRCCS Istituto Nazionale Tumori Milano, Pathology, Milano; ³IRCCS Istituto Nazionale Tumori Milano, Nuclear Medicine, Milano; ⁴IRCCS Istituto Nazionale Tumori Milano, Medical Oncology, Milano, Italy.

Background: Pregnancy-associated melanoma (PAM) has been associated with poorer outcomes, although the prognostic role of pregnancy remains controversial. Management of PAM is challenging, as no established guidelines are available. Delays in detection and treatment are common and may worsen prognosis. Safety of Sentinel Node Biopsy (SNB) in pregnant patients is debated. We report our institutional experience in managing PAM.

Methods: We retrospectively reviewed 33 pregnant women surgically treated for cutaneous melanoma at Istituto Nazionale Tumori, Milan, Italy, between 2007 and 2023.

Results: Diagnosis was made between 7^th and 32^nd week of gestation: 31 patients presented with primary invasive melanoma and 2 with regional nodal recurrence. Surgery was performed during pregnancy in 27 women (81.8%), while 6 (18.1%) underwent surgery after delivery due to diagnosis after the 30^th gestational week. Wide local excision with SNB was performed in 28 women (84.8%), 3 patients (9.1%) did not undergo SNB for concerns regarding fetal safety and presented with clinically evident nodal disease. At diagnosis, 11 women (33.3%) had advanced disease (10 stage III, 1 stage IV M1a), 22 (66.7%) had a negative SNB (7 stage IA, 9 stage IB, 3 stage IIA, 1 stage IIB, 2 stage IIC; according to AJCC VIII Edition). No fetal complications occurred. After a median follow-up of 59 months, 25 women (75.7%) were alive without evidence of disease, 1 (3.0%) was alive with metastatic disease, and 7 (21.2%) died of disease.

Conclusions: SNB can be safely performed after the first trimester without fetal complications and should be offered to pregnant patients. Surgery should not be delayed, as it allows accurate staging and higher prognostic chances. Consistent with previous reports, our cohort showed a higher rate of advanced disease at diagnosis, likely due to diagnostic and therapeutic delays. Larger series are needed to better define prognostic impact of pregnancy on melanoma outcomes.