P-0149 - Anorectal malignant melanoma – experience of a single Portuguese institution
|Date||28 June 2014|
|Event||World GI 2014|
|Topics|| Melanoma and other Skin Tumours
|Citation||Annals of Oncology (2014) 25 (suppl_2): ii14-ii104. 10.1093/annonc/mdu165|
I. Miguel1, M. Passos2
Anorectal melanoma is an uncommon type of cancer with a poor prognosis. Although it comprises only 0.4 – 1.6% of all melanomas, it is the third most common location after cutaneous and ocular melanoma. It represents 1% of anal canal cancers. The disease is usually diagnosed between the age of 60 and 80, and has a female predominance. Patients usually complain of rectal bleeding and/or pain and a mass sensation. Surgery is the treatment of choice. Chemotherapy, radiotherapy and immunotherapy should be taken into account in order to influence survival.
Retrospective review of 15 patients treated for malignant anorectal melanoma at a Cancer center in Lisbon between 2000-2011. Data on clinical presentation, diagnosis and management was reviewed. Primary endpoint was 1 and 3-year survival.
Of the 15 patients identified, five were excluded because they had been transferred from or to other centers and were lost to follow-up or had incomplete data. Ten patients had complete data and follow-up at our center. Eight patients were females (80%) with a median age of 70.5 years (32-79). Clinical complaints were haematochezia (8), anal pain (4), mass sensation (3) and rectal tenesmus (1). Tumor location was: anal (7), rectal (1), anorectal transition (1) and both rectal and transitional (1). Three patients had distant metastasis at diagnosis (30%) and surgery was not performed, one case had adjuvant chemotherapy (dacarbazine) and two patients best supportive care. Abdominal-pelvic resection (APR) was performed in 5 patients, local resection in one case, and another patient was diagnosed on the histology of a previous hemorrhoid surgical procedure. Six patients relapsed at a median time of 5,4 months. Local relapse occurred in 3 patients (two of them had previous local resection and one APR): one case was treated with a new local resection + radiotherapy, another had local resection + dacarbazine, and the APR patient only had radiotherapy. Distant metastasis occurred in 5 patients (liver – 3, lung – 2, bone – 1, peritoneum – 1). One-year survival was 30%, 3-year survival was 20%.
Anorectal melanoma is an aggressive cancer that in our case series presented with metastatic disease in 30%, while 50% developed metastasis. Surgery is the cornerstone of treatment but the best technique is still in discussion since only small case series have been published, nevertheless the two patients in our sample that had local resection relapsed locally. Locoregional radiotherapy in addition to surgery could be a viable option in local recurrence control. No systemic therapy is considered standard of care for advanced anorectal melanoma and regimens used are extrapolated from the experience for advanced skin melanoma.