Survival Outcomes in Patients Undergoing Pelvic Exenteration for Pelvic Mucosal Melanomas: Retrospective Single Institution Australian Study.

Background: Pelvic mucosal melanomas, including anorectal and urogenital melanomas, are rare and aggressive with a median overall survival of up to 20 months. Pelvic mucosal melanomas behave differently to its cutaneous counterparts and presents late with locoregional disease, making pelvic exenteration its only curative surgical option.

Objective: This study aimed to evaluate the survival outcomes post pelvic exenteration in pelvic mucosal melanomas at Royal Prince Alfred Hospital.

Design: Retrospective case series from a prospectively collected pelvic exenteration database from October 1994 to November 2023.

Setting: Royal Prince Alfred Hospital (quaternary institution), Camperdown, New South Wales, Australia.

Patients: Seven patients undergoing pelvic exenteration for pelvic mucosal melanoma.

Main outcome measures: Overall survival, disease-free survival, and complication rates.

Results: Of the seven patients, most were female (n = 5, 71.4%) and had a median age of 65 years (range, 36-79). Five patients (71.4%) underwent pelvic exenteration for primary pelvic mucosal melanoma; 3 of which were anorectal and 2 vaginal melanomas. Two patients (28.6%) had recurrent anorectal melanoma and received neoadjuvant radiotherapy following an initial wide local excision. Three patients (42.9%) required total pelvic exenteration, while 2 required a central pelvic exenteration (28.6%). The remaining procedures were a central and lateral pelvic exenteration; along with anterior, central and lateral pelvic exenteration. Median length of hospital stay was 19.7 days. Five patients had postoperative complications with one major complication (Clavien-Dindo IIIa). At the study's completion, there were 4 mortalities. Mean survival was 23.6 months (range, 2-100) with a recurrence rate of 83%. Median time to recurrence was 3 months, despite 6 patients (85.7%) having R0 resections. Distant recurrence, i.e. to bone, lung and liver was most common.

Limitations: Small study cohort due to rarity of disease, limiting generalizability.

Conclusion: Pelvic exenteration for pelvic mucosal melanoma appears to help control local disease as recurrence is most commonly distant or regional. See Video Abstract.