By Mark Emberton, MDJuan Gómez Rivas, MD

Focal therapy is a treatment option for men with specific types of localized disease. This treatment attempts to ablate areas of the prostate that contain cancer, while sparing healthy tissue. This article covers both technical and practical information about HIFU.

WHAT IS HIFU?

High-intensity focused ultrasound (HIFU) is a non-invasive, radiation-free technique that uses heat to destroy the area of the prostate gland affected with cancer, by means of a probe that emits a beam of high-intensity focused ultrasound. It can heat small amounts of tissue to within a few millimetres of accuracy, destroying tissue only in this area. This is known as focal therapy. More than 50,000 men around the world have been treated with focused ultrasound for prostate cancer. It is the leading clinical application of the technology. There are two focused ultrasound systems approved in the US for the ablation (destruction) of prostate tissue: SonaCare’s Sonablate and EDAP’s Focal One.

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF HIFU?

Advantages

  • You only need a short hospital stay: you can usually go home on the same day as your treatment.
  • The recovery time is short: usually one week.
  • HIFU doesn’t involve any major surgery.
  • You may be able to have HIFU again if your cancer comes back after your first HIFU treatment.
  • You may also be able to have other treatments after HIFU if your cancer comes back, such as surgery or radiotherapy.

HIFU may be able to treat only the part of the prostate that contains significant areas of cancer, and therefore eliminate any active cancer tissue. These major benefits can reduce the risk of disease progression, causing fewer side effects and improving quality of life compared to radical treatments (radical prostatectomy or radiotherapy), especially regarding sexual and urinary aspects.

Disadvantages

  • HIFU is only available in specialist centers or as part of a clinical trial. It might not be available in a hospital near you.
  • Compared with other treatments, we don’t know as much about the risk of side effects or how well it works in the long term (after 10 years).
  • As with other treatments, you may get side effects which are explained later in this article.

AM I ELIGIBLE FOR HIFU?

Criteria are different depending on patents characteristics, centers, and clinical trial involved. HIFU might be suitable for you if your cancer is contained inside your prostate (localized). It’s sometimes an option if your prostate cancer has started to break out of your prostate, or has spread to the surrounding area (locally advanced prostate cancer). It’s not an option if your cancer has spread outside your prostate to other parts of your body (advanced prostate cancer). HIFU can also be used to treat cancer that has come back after radiotherapy (recurrent prostate cancer). This is called salvage HIFU. 

BEFORE YOUR TREATMENT

If you’re having focal HIFU, you will usually go to a screening appointment first. You’ll have a magnetic resonance imaging (MRI) scan, which produces detailed images of the prostate and shows the location of the cancer. You may also have a prostate biopsy, which shows the location of the cancer and how likely the cancer is to grow and spread outside the prostate. These tests will help your surgeon target the area of the prostate that needs to be treated.

TREATMENT STRATEGIES

Courtesy of: V. Kasivisvanathan, M. Emberton, H.U. Ahmed. Focal Therapy for Prostate Cancer: Rationale and Treatment Opportunities. Clinical Oncology 25 (2013) 461e473

Courtesy of: V. Kasivisvanathan, M. Emberton, H.U. Ahmed. Focal Therapy for Prostate Cancer: Rationale and Treatment Opportunities. Clinical Oncology 25 (2013) 461e473

Figure 1: Diagrammatic representation of focal therapy strategies. The red lesion represents clinically significant prostate cancer, and the green lesion represents clinically insignificant prostate cancer. The yellow circles represent the neurovascular bundles, and the blue rectangle represents the ablation zone. Lesion-targeted therapy is represented by (a)–(c). In (a), unifocal ablation preserves the contralateral neurovascular bundle. In (b), although clinically significant cancer is present bilaterally, one neurovascular bundle is still spared. In (c), clinically insignificant cancer near the second neurovascular bundle is not treated. Only the index lesion is treated, allowing preservation of one neurovascular bundle. In (d), an example of region-targeted therapy, hemi-ablation, is presented.

AFTER YOUR TREATMENT

You should be able to go home on the same day as your treatment. Your doctor or nurse will check that you’ve recovered from the anesthetic and are fit to go home. You may have pain in the area between your testicles and back passage, but you’ll be given pain-relieving drugs to take at home. You will also get antibiotics to prevent any possible infection, and may be given a medicine called a laxative to help you empty your bowels. HIFU usually causes the prostate to swell initially, which can make it difficult to urinate. You’ll have a catheter to drain urine from your bladder until the swelling goes away, usually for up to a week after treatment.

WHAT ARE THE SIDE EFFECTS?

Like all treatments, HIFU can cause side effects. These will affect each man differently, and you might not get all of them. The most common side effects are urinary problems. You’re more likely to get side effects if you have more than one HIFU treatment or if you’ve had other treatments for prostate cancer before HIFU. This is because your first treatment may have already damaged the area around your prostate. Less of the healthy tissue is damaged during focal HIFU than whole-prostate HIFU, so some experts believe it may cause fewer side effects than whole-prostate HIFU. But we need more research before we know if there is a difference in the risk of side effects. These can develop soon after your treatment and may include:

  • Blood or tissue in your urine
  • Urinary infections
  • Urinary retention
  • Testicle infections
  • An opening between the back passage and the urethra (rectal fistula), This is uncommon, (occurs in 1/800 cases).

You will have check-ups with your doctor or nurse at the hospital. This is often called follow-up. The aim is to:

  • Check how your cancer has responded to treatment
  • Deal with any side effects of treatment
  • Give you a chance to raise any concerns or ask any questions

You will have PSA tests every three to six months for the first few years to check how well the HIFU has worked. You may also have a prostate biopsy or MRI scan after treatment to ensure your prostate cancer has been treated. If you have focal HIFU, you might have low-risk cancer in another area of the prostate that is not treated on purpose. You will have regular tests to monitor the cancer that is not treated. These might include PSA tests, MRI scans, and prostate biopsies. A continuous rise in your PSA level can be a sign that the cancer has come back. If your cancer does come back, your doctor or nurse will talk with you about further treatment options. You might also have other tests, such as a CT scan, MRI scan, or bone scan, to see if the cancer has spread to other parts of your body. ▲

 Mark Emberton, MD, presenting at the 2016 Prostate Cancer Conference

 Mark Emberton, MD, presenting at the 2016 Prostate Cancer Conference


Comment