AUA2022: REFLECTIONS Focal Therapy for Prostate Cancer: Should It Replace the Standard of Care?
By: Michael O. Koch, MD; Kelly Stratton, MD; Scott Eggener, MD | Posted on: 01 Sep 2022
Prostate cancer is and has been for many years the most diagnosed cancer in men. Unlike many other cancers, 97.5% of newly diagnosed men with prostate cancer survive at least 5 years and of men with localized prostate cancer, 100% survive at least 5 years. Consequently, treated men will experience the potential side effects of therapy for many years to come. While there has been a gradual adoption of active surveillance in men with low-risk prostate cancer and an increased use of aggressive surgical management in men with high-risk prostate cancer, there has been very little change in intermediate-risk prostate cancer with about 40% of patients being treated with radiation and another 40% being treated with surgery. Apart from technological advancements in surgery and radiation, men with intermediate-risk prostate cancer are treated today in essentially the same way that they were 20–30 years ago.
SEER (Surveillance, Epidemiology, and End Results) data suggest that many men have major decisional regret occurring in 15.0% managed surgically and 16.2% managed with radiation.1 Sexual function and bowel bother were the major drivers of this dissatisfaction depending on the approach used. The awareness of patient unhappiness with standard therapy drives many patients to seek out alternative approaches.
The concept of focal therapy or the “male lumpectomy” was originally proposed by Onik et al in 2008, and favorable results were reported in 48 patients over the short term.2 This prompted a consensus conference led by experts in the field to propose that focal therapy should be explored as an alternative for small incidental tumors that same year. Most were dismissive of focal therapy for larger or intermediate grade tumors because of the known multifocality of most prostate cancers and the concern that we could be leaving untreated areas that harbored small foci of cancer, even with careful screening of patients. Today, we recognize that these small foci of well differentiated cancers harbor very little biological risk and can be safely followed. Since the original proposals for adoption of focal therapy, we have had major advances in prostate cancer imaging with multiparametric MRI and prostate-specific membrane antigen scans and we now have multiple technologies to ablate prostate tissue.
The largest cohort of men treated with focal therapy comes from the United Kingdom, with 1,379 patients treated in a multi-institutional cohort with focal high-intensity focused ultrasound.3 Depending on the risk group, 70%–80% of patient had avoided whole gland therapy at 7 years. Functional results are excellent, exceeding those of surgery or radiation with International Index of Erectile Function scores returning to near baseline within 6 months.
Today, we should very carefully consider patients for focal therapy if they have significant enough disease to warrant treatment, the disease is confined to 1 portion of the prostate and not involving the sphincter, optimally but not necessarily seen on MRI, and not judged to be high risk enough to warrant wide resection or pelvic lymph node dissection.
Table. Focal therapy options with advantages and disadvantages
|Cryotherapy||Most ablative, widely available||Very large (>80 ml) or small prostates (<20 ml), post-transurethral resection of the prostate, median lobes|
|High-intensity focused ultrasound||Precise and easy to follow prostate contour||Large prostates (>40 ml), anterior and apical tumors, calcifications|
|Laser ablation||Magnetic resonance guided, magnetic resonance confirmation of ablation||Large lesions|
|Transurethral Ultrasound ablation||Magnetic resonance guided, No significant prostate size limitations, Magnetic resonance confirmation of ablation||Prostate calcifications|
Fortunately, today we have multiple modalities available to focally ablate prostate tissue and a growing experience with the advantages and disadvantages of each approach. Several of the more developed technologies are listed below (see Table). Each of these technologies has aspects that make it a favorable approach or an unfavorable approach in certain patients. While there are advocates of all these approaches touting their advantages, limitations such as tumor location, prostate size and calcifications mean that the successful focal therapist will be familiar and able to offer at least 2 of these technologies so that they can effectively treat all appropriate patients. We do not have the data or followup today to conclude that these techniques should become the standard of care. We do have enough data, however, to conclude that side effects of treatment compared to conventional approaches is relatively minimal and, in the intermediate term, these technologies allow most men to avoid whole gland therapy and continue active surveillance protocols. Many men will choose these approaches even knowing that some will eventually require retreatment or whole gland therapy. Side effects of sexual dysfunction and loss of urinary or bowel function are major dissatisfiers and, in the view of many well-educated patients, this approach will be considered a very valuable trade-off.
- Hoffman RM, Lo M, Clark, et al. Treatment decision regret among long-term survivors of localized prostate cancer: results from the prostate cancer outcomes study. J Clin Oncol. 2017;35(20):2306-2314.
- Onik G, Vaughn D, Lotenfoe R, et al. “Male lumpectomy”: focal therapy for prostate using cryoablation. Urology. 2007;70(6):16-21.
- Reddy D, Peters M, Shah T, et al. Cancer control outcomes following focal therapy using high-intensity focused ultrasound in 1379 men with non-metastatic prostate cancer: a multi-institutional 15 year experience. Eur Urol. 2022;81:407-413.