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External-beam radiotherapy (EBRT) is a curative treatment of localised prostate cancer. The local recurrence rate is between 25 and 32% but might apparently be much higher. The prognosis for patients with a biochemical recurrence following radiotherapy is poor: D’Amico in 2003 reported a biochemical recurrence rate of 39% after radiotherapy and five years after biochemical recurrence 23% of patients had died. The risk of death was correlated with the patient initial Gleason score.
It therefore appears logical to propose curative salvage treatment for patients with a local recurrence after radiotherapy whose life expectancy is ?5 years. The standard curative treatment is radical surgery; more recently, cryotherapy and brachytherapy have been proposed. Highintensity focused ultrasound (HIFU) represents a new alternative. The objectives of the study were to evaluate the efficacy and toxicity of treatment by HIFU and to define the criteria of selection of patients.
Materials and Methods
One hundred and eighteen patients were selected for HIFU treatment of a histologically documented local recurrence after radiotherapy. All patients showed a biochemical recurrence according to the American Society for Therapeutic Radiology and Oncology (ASTRO) criteria. No patients had metastases on bone scan, abdominal computed tomography (CT) scan and/or pelvic magnetic resonance imaging (MRI).
The mean radiotherapy dose was known in 89 patients: 68.8 Grays (range 56–88 Grays). The mean interval between radiotherapy and HIFU treatment was 56.5 months (4.1 years).
Fifty-nine patients received hormone therapy in combination with external radiotherapy or because of biochemical recurrence following radiotherapy. All hormone therapies were discontinued at the time of HIFU treatment.
Treatment with High-intensity Focused Ultrasound
Treatments with HIFU were performed using the ABLATHERM® device manufactured by EDAP-TMS (France). From October 1995 to March 2002, treatments were given using standard parameters. From September 2002 onwards, specific treatment parameters were defined to take account of the poor vascularisation of the prostate gland and peri-prostatic tissue as a result of the fibrosis induced by irradiation. These parameters were calculated using the mathematical model developed by INSERM. The principal objective was to eliminate the risk of rectal lesions caused by an excessive thermal dose delivered to the gland. Sixty-three patients were treated with these specific parameters.
Treatments were performed under spinal anaesthesia, except in the case of contraindications requiring general anaesthesia.
HIFU treatment was given by adjusting the volume treated as precisely as possible to the volume of the gland. In general, treatment was administered in four successive blocks (two per prostate lobe). The catheter replaced at the end of treatment was withdrawn on the fourth day post-operatively. The integrity of the rectal wall was monitored in all patients by MRI with gadolinium injection (and by rectoscopy in the event of abnormalities detected on MRI).