What is that evidence?
In the essay, Dr. Lebastchi and colleagues point to a number of single-arm studies with encouraging efficacy and safety results. They also highlight a phase 3, randomized trial that they were involved in: This compared focal therapy (partial gland ablation with vascular-targeted photodynamic therapy) with active surveillance in early-stage disease and uniformly showed better post-treatment biopsy (disease/no disease) and conversion-to-prostatectomy results with the focal therapy out to 4 years (J Urol. 2018;200:786-793).
However, that study did not have an active treatment comparator. For that gold standard, there is now anticipation for results from the CHRONOS trial in the United Kingdom, especially part A of the trial, which compares radical therapy to focal therapy (HIFU or cryotherapy), with 5-year progression-free survival as the primary outcome. That trial is slated for completion in 2027.
Until then, the lack of prospective randomized clinical trials and long-term follow-up “hinders acceptance [of focal therapy] in the urology community,” the essay authors comment.
Meanwhile, careful patient selection is very important, they say.
The latest relevant guidelines state that appropriate candidates are men with a solitary, well-defined index lesion; patients with bilateral multifocal lesions; or very advanced tumors that are not appropriate for the focal approach.
A multidisciplinary international expert panel recently convened to establish guidance for clinicians offering focal therapies and then published a consensus statement to advise practitioners and researchers.
UCSF’s Dr. Cooperberg sees plenty of room for improvement among focal therapy practitioners and investigators. “From an outcomes standpoint, follow-up protocols and definitions of success remain inconsistent. I believe we’re making progress in all these areas, but we’re not there yet,” he says.
To date, some patients have been managed poorly, Dr. Cooperberg added. “We certainly see many patients who have been inadequately counseled as to HIFU’s advantages and disadvantages, with sometimes disastrous results.”
Some of those unfortunate results may have arisen from the U.S. Food and Drug Administration’s initial approval of HIFU in 2015, which was for use in ablating prostate tissue in general and not cancer specifically. This approval generated confusion, one expert commented at the time: “The FDA doesn’t specify whether it’s for benign or malignant disease; it’s a bit vague, like saying you can drive this car, but we’re not going to tell you how to drive it,” said Manoj Monga, MD, from the Cleveland Clinic.
Dr. Lebastchi has disclosed no relevant financial relationships; co-author Inderbir Gill, MD, is an unpaid consultant for Steba Biotech, and co-author Andre Luis Abreu, MD, is a consultant for Koelis and was a proctor in training for Steba Biotech. Dr. Cooperberg is a consultant for Alessa Therapeutics.
A version of this article first appeared on Medscape.com.