Feedback thermotherapy for benign prostatic enlargement : A clinical and methodological evaluation

Abstract: The purpose of this thesis was to evaluate a new treatment strategy for symptomatic benign prostatic enlargement.The transurethral thermotherapy (TUMT) antenna design was studied. The design influences the heating-profile significantly and the absorbed energy in a target volume were only about 13-20% of the energy delivered.The temperature distribution in the prostate was modelled for a typical TUMT catheter at various blood-flow rates. The volume of tissue destroyed was simultaneously calculated from cell survival data after thermal exposure. Blood-flow rate is a key factor in the outcome of TUMT. Three patients were accrued for simultaneous feed-back thermotherapy and positron emission tomography (PET) to study the changesin intraprostatic blood-flow during the treatment. Large variations in blood-flow were seen during treatment.To evaluate whether the results after TUMT improve using high intraprostatic temperatures of 55° C or greater, 30 men were accrued for treatment with simultaneous intraprostatic temperature monitoring. High intraprostatic temperatures relieved bladder outlet obstruction in 60% of the patients and had a good effect on symptoms. To study the difference between patients with a favourable outcome after feedback thermotherapy with patients with less favourable outcome, 21 patients were enrolled for videourodynamics. Patients still suffering from bladder outlet obstruction had significantly smaller cross sectional area at the level of the bladderneck than unobstructed patients.Conclusions: Intraprostatic temperature control is mandatory to optimise the results after microwave thermotherapy. With intraprostatic temperature control the number of patients with favourable outcome increases. Patients with less favourable outcome might be under treated at the level of the bladderneck.