There were no significant differences between those who returned the questionnaire and those who did not regarding; age (U = 716, p = 0.620), PSA-values (U = 982, p = 0.170), time since primary diagnosis and time since metastatic disease (U = 798, p = 0.842, U = 698, p = 0.631), analgesic use (χ2 = 0.697, p = 0.325) or tumor status (T, N, M, and Gleason score) (ranging between χ2 = 0.319˗5.062, p = 0.653˗0.989). The gene discussed is KLK3; the disease is metastatic neoplasm.