The third cause of cancer mortality in men, prostate cancer is known for its slow progression… “until it accelerates”underlines Professor Pascal Rischmann, urological surgeon and former president of the French Association of Urology and the National Academy of Surgery, during a press briefing. Medical interventions are limited to two extremes for localized cancers: active surveillance and radical therapies (radical prostatectomy, radiotherapy, brachytherapy). Although they are of interest, there remains a need for therapeutic de-escalation in this cancer to avoid overtreatment at intermediate stages.
This is where a new but still experimental technology comes in: high-intensity focused ultrasound (Hifu). This alternative fits between the two options for low or intermediate risk cancers. It makes it possible to save the organ and preserve healthy tissues by performing a focal treatment. The ultrasound wave passes through healthy tissue without aggression and then converges on the target location, heating it in a manner similar to a laser. The resulting coagulation necrosis destroys tissues, including cancerous tissue.
Better urinary continence
In 2014, the High Authority for Health authorized the technique for a French clinical study, the Hifi trial., aimed at validating the Hifu technique in prostate cancer. Some ten years later, the proof of its effectiveness is clear: ultrasound treatment of a prostate tumor improves survival without treatment and preserves urinary and sexual functions, one of the main concerns of patients. “We are fully out of the experimental phase, the technique is validated”rejoices Professor Rischmann, principal investigator of the trial.
The results of the study are published in the journal European Urology. Conducted between 2015 and 2019 among 3,300 patients with low or intermediate risk prostate cancer in 46 centers, the clinical trial demonstrates the non-inferiority of total or partial Hifu on the survival rate without salvage treatment at 30 months: 90% versus 86% in radical prostatectomy (Hazard Ratio = 0.71).
We are fully out of the experimental phase
Professor Pascal Rischmann, principal investigator of the Hifi trial
The strict urinary continence measurement score (no leak versus at least one leak per day) was significantly less degraded for the intervention group (29%) than for the control arm (44%) (relative risk = 0.66) . In terms of erectile function, its loss was less under Hifu.
A non-ionizing therapy in a single session
Minimally invasive therapy is customizable according to the sextants concerned and the tumor volume. The authorization issued by the HAS required treating at least 70% of the prostate to ensure patient safety in this experimental clinical trial. But ultimately, the goal is to treat the smallest area possible (with safety margins of 1 cm) to reduce side effects.
Ultrasound only takes one session, approximately one hour (variable depending on the volume treated) while radiotherapy requires 30 to 40 sessions. “It is possible to treat three to four patients in a single day”comments Professor Rischmann. In 10% of cases, patients need salvage treatment, including radiotherapy indicated beyond the age of 70. The advantage of initial therapy with Hifu is the reduction in toxicity compared to initial radiotherapy when salvage treatment is required (patient exposure after salvage treatment: respectively 74 Gray versus 78 to 93 Gy).
A culture to acquire
“The Academy welcomes the results which show that urological surgeons are not content with wielding the scalpel,” transmits Dr Hubert Johanet, permanent secretary of the National Academy of Surgery. He applauds “the culmination of the validation of a very long work, started in 2010”. The visceral surgeon describes the study as a “great success” but regrets that it takes fourteen years of evaluation process, too long compared to the speed of medical progress. “We need to think about ways to advance major innovations more quickly”while guaranteeing patient safety.
To develop Hifu in operating practice, “it’s not a question of training: it’s a culture”defends Professor Rischmann. For him, this culture is based on three pillars: good patient selection; the quality of the treatment carried out by the surgeon and the follow-up of the patient who is at a slightly higher risk of seeing another cancer appear in an untreated prostate area (20%) and could require a second session. “With 1,500 urologists in the region, the use of the technique will spread very quickly”.
The urological surgeon also emphasizes the role of the general practitioner. He notes that the practice of rectal examination is declining despite its importance in screening. It also warns about the level of information of doctors regarding technical developments: “They have not yet realized the importance of the contribution of technology by Hifu. They must have clear information, and their knowledge of the technique must not be based on rumors. General practitioners are on the front line, they are the ones patients come to see, with their questions and concerns.”
