Park JS, et al. - For patients with large bowel melanoma metastases, the incidence, clinical characteristics, and survival were determined. Findings revealed an incidence of 0.3% for melanoma metastatic to the colon, rectum, and anus. Between diagnosis of primary melanoma and large bowel metastasis, there could potentially be a long interval. While some patients were asymptomatic, rectal bleeding was the most commonly observed symptom in these patients.

Methods

• All patients with melanoma treated over a 50-year period (1964–2014) at a tertiary referral center were reviewed.
• Cases diagnosed with melanoma metastases in the colon, rectum, and anus were selected for this study.
• Researchers excluded primary colorectal and anal melanomas.
• Patient demographics, clinical features, and survival data was collected.

Results

• Researchers identified 38,279 patients with primary melanoma; large bowel metastases was noted in 106 of these patients (0.3%, mean age 51.0 years [standard deviation 16.3], 64 males).
• Findings revealed a median interval of 62.8 months (range 1–476) between diagnosis of primary melanoma and large bowel metastasis.
• Rectal bleeding (29.2%) was identified as the most common symptom, and the large bowel was the sole site of metastasis in 47.2% of patients.
• From diagnosis of large bowel metastasis, median survival was 31.7 months (range 1–315), and overall survival at 1, 2, and 5 years was 68.1, 45.9, and 26.5%, respectively.