Focal Laser Ablation Effective for Prostate Cancer
International registry study highlights MRI’s role in detecting recurrence after focal laser ablation
Findings from an international registry study suggest that transperineal focal laser ablation may offer an effective treatment option for carefully selected men with localized prostate cancer, while helping patients avoid the side effects associated with more aggressive therapies.
One year after treatment, 83% of patients required no additional whole-gland therapies, and MRI proved highly accurate in identifying most clinically significant cancer recurrences.
“A lot of patients really would like to have focal treatment for prostate cancer rather than having a full prostatectomy, which can lead to incontinence and/or impotence,” said lead author Katelijne de Bie, MD, of the Department of Urology at Amsterdam University Medical Center.
According to Dr. de Bie, transperineal laser ablation (TPLA) is a minimally invasive treatment that can be used for focal treatment of localized prostate cancer. It involves inserting very thin laser fibers through the perineum into the prostate under US guidance, then heating the fibers with laser energy to induce cell damage, thereby destroying the malignancy.
Previous research suggests the potential pool of candidates for TPLA may be significant, although estimates vary substantially depending on patient-selection criteria.
“Because previous studies of TPLA outcomes only have included small numbers of patients at a single location, we wanted to gather all our data and knowledge about all our treated patients to see if we can do something about the quality of this treatment,” Dr. de Bie explained.
She and her team assessed the one-year outcomes of 195 patients who underwent TPLA at four sites (three in Europe and one in the U.S.) between May 2018 and June 2023. The treated tumors had a median length of 11 mm and had been identified as PI-RADS 3 or higher lesions on MRI and confirmed through biopsy.
A combination of prostate-specific antigen (PSA) testing, MRI and prostate biopsy was used to determine if cancer had recurred in the area where TPLA was performed.
The researchers found that 17% of the patients had a biopsy-confirmed, clinically significant recurrence of their cancer, requiring a repeat focal laser ablation or an additional treatment. “It shows this treatment is not perfect yet, but that it has great potential, because most of the patients do not have recurrence,” Dr. de Bie said.
Patients also experienced significantly lower rates of side effects than those associated with other treatments.
Preablation, postablation, and recurrence multiparametric MRI scans in a 63-year-old man treated with transperineal focal laser ablation (TPLA) for localized prostate cancer (PCa). Clinical parameters included an initial prostate-specific antigen (PSA) level of 7.2 ng/mL, a Prostate Imaging Reporting and Data System (PI-RADS) grade 4 lesion (red circles) in the right apical peripheral zone, and a maximum tumor length of 5 mm. MRI-guided targeted biopsy confirmed a Gleason score (GS) 3+4 prostate cancer tumor. (A) Preablation axial T2-weighted MRI scan and apparent diffusion coefficient (ADC) image shows the apical PI-RADS 4 lesion (circles). (B) Six-month postablation axial T2-weighted MRI scan and ADC image show cystic necrosis (arrows). There was no evidence of recurrence; the PSA level was 1.5 ng/mL. (C) One-year after ablation, the patient’s PSA level had increased to 4.3 ng/mL. Axial T2-weighted MRI scan and ADC image show a recurrent lesion (blue circles) in the right apical peripheral zone adjacent to the ablation scar. Targeted biopsy confirmed GS 3+4 prostate cancer, which was classified as in-field recurrence (IFR) of clinically significant PCa and subsequently re-treated with TPLA. In summary, serial multiplanar MRI demonstrates treatment response after TPLA with postablation necrosis, followed by MRI-detected IFR confirmed with biopsy at 12-month follow-up. Multiparametric MRI was performed with a 3.0-T MRI scanner (Skyra; Siemens Healthineers) using T2-weighted, diffusion-weighted, and ADC sequences, with gadobenate dimeglumine contrast material administration (Bracco Diagnostics).
https://doi.org/10.1148/radiol.251658 ©RSNA 2026The recurrence rate is a reasonable number, according to Aytekin Oto, MD, of the Department of Radiology at the University of Chicago. “Ideally, you want to make that number zero, but 17% is in line with what’s listed in the literature, and it’s closer to the lower end of that,” he said.
Both doctors note that focal therapy may sometimes undertreat part of the cancer, which can potentially lead to significant cancer residue or recurrence, requiring additional treatment. Dr. Oto cautioned that MRI has been shown to underestimate the extent of tumors, making complete tumor delineation vitally important. “There has to be an adequate margin around the MRI-detected lesion,” he advised.
“We found that MRI results at six- to 12-months after treatment were a good predictor of whether a targeted follow-up biopsy would confirm cancer recurrence in the treated area,” Dr. de Bie said.
MRI correctly identified 81% of clinically significant biopsy-confirmed recurrences, with 83% sensitivity and 89% specificity.
Experienced urologic radiologists at each center reviewed the MRI scans. MRI grades of PI-RADS 3 or higher after 12 months were considered positive and were chosen for biopsy. “There is a lot of discussion worldwide of the use of PI-RADS,” Dr. de Bie said. “If you see a PI-RADS 4 or 5 lesion, it’s quite predictive of clinically significant disease. Alternatively, if a patient’s MRI is negative but his PSA is rising, you must perform a biopsy.”
Dr. Oto said the study results are encouraging but cautioned that there’s still a need to specify which MR findings are more suggestive of recurrence. “In future studies prostate-specific membrane antigen (PSMA) PET/CT scan potentially could play a role in determining both recurrent and de novo cancer,” he said.
Dr. de Bie and her team note that PSMA PET may not always be useful due to inflammation and post ablation effects that can create false positive results and contribute to patient angst.
Multiple Modalities Needed for Accurate Tumor Location
Dr. de Bie and her colleagues call for developing standard treatment and follow-up protocols for TPLA. “It’s really important for this treatment to become more standardized, because you need large numbers to improve the efficacy and benefits of the treatment,” she said.
Dr. Oto believes that precisely identifying the location of the tumor being treated is crucial for this goal, and that it requires a combination of diagnostic techniques, with MRI continuing to play a key role.
“About 30% of time there’s discordance. One modality may show cancer that may be missed by another modality,” he observed. “Typically, we put together all three—biopsy, PET and MRI—to understand where the disease is and to determine whether the patient is appropriate for focal ablation or not.
“We need to make sure there’s no cancer elsewhere in the prostate,” he elaborated. “If we see the lesion on the right side but find more cancer growing on the left that we missed, it doesn’t help the patient’s prognosis.”
“When these intricacies are fully considered, focal ablation has a big advantage by decreasing the complications while still treating the cancer,” Dr. Oto said.
Both he and Dr. de Bie also pointed out that focal ablation provides the added advantage of allowing for another procedure if needed later.
“You could undergo it a second time if needed and avoid prostatectomy for a long time—even prevent it,” Dr. de Bie speculated. “It’s really helpful for patients who are sexually active and or fear the risk of incontinence.”
For More Information
Access the Radiology study, “One-year Follow-up after US-guided Transperineal Focal Laser Ablation of Localized Prostate Cancer: Worldwide Registry Study.”
Read previous RSNA News stories on prostate cancer: