ObjectivesTo evaluate the durability of benefit associated with cooled high-energy thermotherapy (cooled thermotherapy) using the Targis System with data extending to 5 years after treatment. MethodsAt three centers in Canada and the United Kingdom, 150 patients with benign prostatic hyperplasia underwent cooled thermotherapy with the Targis System. This was an outpatient procedure performed without general or regional anesthesia. Patients were followed up at 1 and 6 weeks, 3, 6, and 12 months, and yearly to 5 years. ResultsPatients were evaluated at 1, 2, 3, 4, and 5 years after treatment (n = 132, 111, 90, 77, and 59, respectively). At these intervals, the American Urological Association symptom scores improved by 11.7 (57%), 12.1 (58%), 11.5 (53%), 10.1 (47%), and 10.6 (47%) points (P <0.0001 for each), the peak flow rates improved by a mean of 4.0 (57%), 4.0 (56%), 3.4 (48%), 3.3 (47%) and 2.4 (37%) mL/s (P <0.0001 for each), and quality-of-life scores improved by 2.6, 2.6, 2.5, 2.3, and 2.3 points (P <0.0001 for each). At least a 50% improvement in the American Urological Association symptom score was observed in 63% to 68% of patients available for follow-up at years 1, 2, and 3 and 50% and 51% of patients available for follow-up at years 4 and 5, respectively. Four patients required repeated microwave thermotherapy, 27 required subsequent invasive treatments, 1 permanent catheterization, 11 required alpha-blockers, and 1 antiandrogen therapy. ConclusionsCooled thermotherapy with the Targis System produces durable improvements in symptoms, quality of life, and flow rates to at least 5 years after treatment.