Prognostic significance of lymph node ratio in patients with Merkel cell carcinoma.

Merkel cell carcinoma is a rare and aggressive metastasizing tumor of the skin. Lymph node metastasis is a significant clinical prognostic factor for overall and disease-free survival in patients with Merkel cell carcinoma. A retrospective medical chart review of 12 Merkel cell carcinoma patients was performed. All patients received treatment at the Medical University of Vienna and underwent lymph node dissection between 1994 and 2013. The lymph node ratio was determined by dividing the total number of positive lymph nodes by the entire number of dissected lymph nodes. A positive lymph node ratio was defined as a number >0 and the negative lymph node ratio was defined by zero. The median follow-up was 44 months (range 4-92). A positive lymph node ratio (range 1.00-0.04) was found in 7 (58%) out of 12 patients of whom 5 (71%) died of disease. A negative lymph node ratio was found in 5 (42%) out of 12 patients of whom 2 (40%) patients died of disease. The disease-specific death rate was higher in patients diagnosed with a positive lymph node ratio compared to patients diagnosed with a negative lymph node ratio. Based on these preliminary findings, there might be a prognostic impact of lymph node ratio in patients suffering from Merkel cell carcinoma.