A 12-month study of the placebo effect in transurethral microwave thermotherapy

To determine the placebo effect of transurethral microwave thermotherapy (TUMT) in the treatment of benign prostatic enlargement (BPE).

A prospective, randomized sham-controlled study in 93 patients (mean age 65, range 50-88) was conducted at two centres comparing TUMT or a sham treatment. Patients randomized to receive sham treatment underwent the same initial procedure as for TUMT, but the complete procedure was simulated on the visual display with no application of microwave energy. If the patient's condition had not improved after 3 months, a second genuine TUMT treatment was given at the patient's request.

After 3 months there were significant clinical and statistical differences in efficacy between the groups; 62% and 18% of patients had a > 50% improvement in symptom score in the treated and sham groups, respectively (P = 0.001). The corresponding changes in flow rate were 36% and 11% (P = 0.002), respectively. After 1 year, 63 patients were divided into those that had TUMT initially, those that had sham initially but subsequently had TUMT and those whose sham procedure had led to sufficient clinical improvement to require no further treatment. The two treated groups had a significant improvement over the sham group.

The benefit from TUMT cannot be due to a placebo effect alone.