KLK3 and cancer: Patients receiving prior treatment with other ARSIs showed a significantly lower PSA response (PSA 50% decline, 88.4% vs. 18.8%; PSA 90% decline, 60.5% vs. 6.2%, P < .001, respectively) and significantly shorter progression-free survival (median: 37 months vs. 4 months; log-rank P < .001) than those without prior ARSI treatment, although cancer status did not differ between the groups.