They identified five risk factors (LDH > upper limit of normal (ULN), number of bone metastases ≥10, PSA >39 ng/ml, presence of lymph node metastasis and hemoglobin ≤ lower limit of normal (LLN)) and the c-index for this model was 0.83, which is marginally better than the c-index of our scoring system [c-index: 0.80; (IQR: 0.79–0.82)]. This evidence concerns the gene KLK3 and metastatic malignant neoplasm in the lymph nodes.