The present invention relates to a Wnt5a protein or peptide thereof possessing Wnt5a signaling properties, such as Foxy5, for use in the treatment of prostate cancer, in particular in patients that have undergone or will undergo radical prosteatectomy. The invention also relates to a method for determining a prognosis for a patient having prostate cancer and a kit for performing said method. The method for determining a prognosis for a patient comprises the steps of: evaluating an amount of Wnt5a protein present in at least part of a sample earlier obtained from the patient and determining a sample value corresponding to the evaluated amount; comparing the sample value obtained in step a) with a reference value associated with a reference prognosis; and, if said sample value is higher than said reference value, concluding that the prognosis for said patient is better than said reference prognosis.