The Role of Surgical Methods in the Treatment of Anorectal Malignant Melanoma (AMM)

Purpose : Anorectal malignant melanoma (AMM) is a rare tumor with a poor prognosis. The aim of this study was to investigate the clinicopathological characteristics and treatment outcomes in patients with AMM. Methods : The study included 21 patients diagnosed with AMM between 2000 and 2010 that were evaluated with regard to age, sex, disease stage, treatment modality, and survival. Stage I, II, and III were defined as localized primary malignant melanoma, regional lymph node metastasis, and distant metastasis, respectively.

Results : In all, 12 (57%) patients were female and 9 (43%) were male; median age was 61 years (range: 30–84 years). Among the 21 patients, 7 (47%) underwent abdominoperineal resection and 8 (53%) were treated using wide local excision. Four (19%) patients were classified as stage I, 10 (48%) as stage II, and 7 (33%) patients as stage III. In total, 10 patients received adjuvant therapy. Median overall and progression-free survival was 12 and 9 months, respectively. The 1-year and 5-year overall survival estimates were 59% and 42%, and progression free survival were 49% and 7%, respectively. Patients aged > 60 years (P = 0.145), female patients (P = 0.076), patients with localized disease (P = 0.045), patients that underwent wide local excision (P = 0.619), and patients that received adjuvant therapy (P = 0.962) had longer survival.

Conclusions : The prognosis of AMM remains very poor and disease stage is the only predictor of survival. Abdomino-perineal resection does not confer an advantage, in terms of survival, in patients with AMM.