The idea of focal therapy is that it is possible to treat cancer cells in one location enough to control cancer while minimizing the damage that leads to urinary, sexual, and bowel side effects.1 Many doctors think this treatment approach is promising.2 However, focal therapy is still considered experimental. One reason is that there are no long-term studies that compare focal therapy with established treatments such as radiation therapy or radical prostatectomy.3
How does focal therapy work?
In most cases, prostate cancer is a “multifocal” disease.2 This term means that cancer cells are usually found in several different locations throughout the prostate. The idea behind focal therapy is that your doctor can find and treat the area with the most aggressive cancer.1,4 This area is called the “index lesion.” It may be the biggest lesion or the lesion with the most abnormal cells. The index lesion is most likely to cause the cancer to metastasize.4 Your doctor will identify the index lesion through biopsy and MRI.2,4
Once the target lesion has been identified, there are different ways to destroy the cancer cells. Cryotherapy uses freezing cold temperatures to kill cancer cells. HIFU uses high-intensity sound waves targeted at the tumor. Laser ablation destroys cancer cells using a focused beam of electromagnetic radiation.1
Focal therapy usually leaves some cancer untreated.2 The untreated cancer is monitored for changes, as it would be with active surveillance.4,5 For this reason, focal therapy has been used to treat low-risk cancer, as an alternative to active surveillance.5 More recently, it has been used to treat intermediate-risk prostate cancer as an alternative to radical treatment.2,4,5 The National Comprehensive Cancer Network recommends focal therapy (cryosurgery or HIFU) only if the cancer comes back (recurs but has not spread) after radiation therapy.3 The NCCN does not recommend focal therapies as a first line of treatment for prostate cancer.3
What does the research show?
A systematic review is a way of comparing and combining the results of several small studies. A systematic review of 43 short-term studies of focal therapy was published in 2014.5 This review included data from 2,232 men treated with focal therapy as a first line of treatment. Their results showed that after focal therapy:
83% to 100% of men no longer had “clinically significant” cancer. Clinically significant cancer is cancer that is likely to impact the quality or length of life. These results were seen in 202 men who had a routine post-treatment biopsy.
Up to one-third of men needed follow-up focal treatment.
Pad-free continence ranged from 95% to 100%, depending on the study. Leak-free rates were 83% to 100%.
Urinary complications were the most frequent treatment side effects. The frequency of urinary retention and urinary tract infections was 0% to 17%, depending on the study.
54% to 100% of patients reported having erectile function sufficient for penetration after focal therapy, with or without medication.
This review also included 115 men treated with focal therapy for cancer that returned after radiation therapy. It is hard to draw conclusions from this small number of men. However, their results showed that after focal therapy:5
90% to 92% of men no longer had clinically significant cancer. These results were seen in men who had a routine post-treatment transrectal ultrasound biopsy.
Up to 41% of men needed additional (salvage) treatment.
5% to 20% of men were diagnosed with metastatic cancer.
Pad-free continence ranged from 87.2% to 100%, depending on the study.
29% to 40% of patients reported potency after focal therapy.
Areas of future research
A large randomized clinical trial is one of the best ways to compare different treatment approaches. Randomized clinical trials have to be planned carefully, and it can take years to get the results. So far, this sort of study has not been done to compare focal therapy with radiation therapy, prostatectomy, or active surveillance.
Long-term studies will provide information about how well focal therapy controls cancer over time.5 It is also important to measure how focal therapy compares with whole gland therapy in terms of side effects and quality of life.
Other important questions for future research are:
Which patients should be treated with focal therapy?
How do the different focal therapies compare with each other?
What is the best way to monitor the untreated cancer after focal therapy?
Lee T, Mendhiratta N, Sperling D, Lepor H. Focal laser ablation for localized prostate cancer: principles, clinical trials, and our initial experience. Rev Urol. 2014;16:55-66.
Donaldson IA, Alonzi R, Barratt D, et al. Focal therapy: patients, interventions, and outcomes--a report from a consensus meeting. Eur Urol. 2015;67:771-777.
NCCN Clinical Practice Guidelines in Oncology. Prostate Cancer. Version 4.2018. August 15, 2018. Accessed February 4, 2019.
Zequi SC. Focal therapy will be the next step on prostate cancer management? Opinion: Yes. Int Braz J Urol. 2017;43:1013-1016.
Valerio M, Ahmed HU, Emberton M, et al. The role of focal therapy in the management of localised prostate cancer: a systematic review. Eur Urol. 2014;66:732-751.