Surgery for gastrointestinal metastases of malignant melanoma - a retrospective exploratory study.

BACKGROUND: Cutaneous melanoma has a rapidly increasing incidence in Sweden, and it has more than doubled in the last two decades. In recent years, new systemic treatments for patients with metastatic disease have increased overall survival. The role of surgery in the metastatic setting has been unclear, and no randomized data exist. Many surgeons still perform metastasectomies; however, the exact role probably has to be redefined. The aim of this single-institution study was to retrospectively examine the safety and efficacy of surgery in abdominal melanoma metastases and to identify prognostic and predictive factors.

METHODS: Retrospective analysis of a consecutive series of all patients with stage IV melanoma with gastrointestinal metastases that underwent abdominal surgery at a single center between January 2010 and December 2018. Fifteen patients who underwent in total 18 abdominal procedures, both acute and elective, were identified and included in the study.

RESULTS: Out of 18 laparotomies, six (33%) were emergency procedures due to ileus (n = 4), small bowel perforation (n = 1), and abdominal abscess (n = 1). Twelve procedures (66%) were elective with the most common indication being persistent anemia (58%, n = 7), abdominal pain and anemia (33%, n = 4), and abdominal pain (8%, n = 1). All procedures were performed by laparotomy. There were 19 small bowel resections, 3 partial colon resections, and 2 omental resections. Radical resection was possible in 56% (n = 10) of cases and 67% (n = 8) when only considering elective procedures. In 17 of 18 procedures (94%), there were mild or no surgical complications (Clavien-Dindo grades 0-I). The median overall survival was 14 months with a 5-year survival of 23%.

CONCLUSIONS: Patients with abdominal melanoma metastases can safely undergo resection with a high grade of radical procedures when performed in the elective setting.

TRIAL REGISTRATION: ClinicalTrials.gov , NCT03879395 . Registered 15 March 2019.