MRI-guided focal cryotherapy for treating prostate cancer

Cryotherapy involves destruction of the tumor by extreme temperature reduction in the prostate. This is a focal treatment‒it treats only the portion of the prostate affected by cancer.

The focal nature of the treatment significantly reduces the adverse effects of the usual treatments of prostate cancer (radiation and surgery), in particular urinary incontinence and erectile dysfunction.

It is also an attractive option because it has minimal impact on quality of life. The treatment is only possible for certain intermediate-risk tumors. These cases must be discussed in a meeting of the various physicians involved in the prostate cancer care.

• The procedure is usually performed in a half-day on an outpatient basis, or in the hospital for one night.
• The procedure is performed under local anesthesia or with sedation (a state of drowsiness induced by an anesthesiologist).
• In the first step, the radiologist uses combined ultrasound/MRI guidance to insert a cryotherapy needle very precisely into the tumor.
• Once the needle is in place, treatment can begin. The end of the needle will be chilled to -40°C, allowing the formation of ice that will completely cover the tumor and cause its destruction.
• When the ice area completely covers the tumor, the freezing is stopped, the needle is withdrawn and the procedure ends.
• In some cases, when the tumor is near the urethra, an indwelling catheter may be necessary from the outset. This can usually be removed within 24 hours after the procedure.

The functional results of various studies confirm the advantages of this technique, especially compared to the usual standard treatments (radiation and surgery):

• Cryotherapy makes it possible to preserve urinary continence in more than 95% of cases
• Cryotherapy makes it possible to preserve erectile function in more than 70% of cases, according to the studies (this depends in particular on the size of the tumor and its proximity to the nerve structures responsible for erection).

Oncological results:

• Around 70% of patients maintain negative biopsies three years after the procedure
• Between 50 and 75% of patients do not require radical treatment (radiation or prostatectomy surgery) five years after cryotherapy.

In the event of focal recurrence, a second cryotherapy session can certainly be considered.

In the event of a more aggressive recurrence that is not accessible by focal treatment, a more aggressive treatment (radiation or surgery) must be considered.

The following are some recent publications on focal cryotherapy for treating prostate cancer:

• Marra and al.  European Urology April 2021 (10 years of follow-up): 96.5% preservation of continence at 10 years; 50% of patients did not need radical treatment
• Oishi and al. American Journal of Urology, December 2019: 97% preservation of continence; 73% preservation of erectile function
• Shah and al. European Urology March 2021: 100% preservation of continence; 84% preservation of erectile function

Before you can receive any focal cryotherapy treatment, you must undergo a specific prostate cancer evaluation, with at least one dose of PSA, an MRI and targeted biopsies.

All of these items allow prostate cancers to be classified as low-risk, intermediate-risk or high-risk (D’Amico classification). Only intermediate-risk patients and, infrequently, low-risk or high-risk patients, can receive focal treatment.

Cases are usually discussed during a multidisciplinary meeting, and the most suitable care is then discussed in consultation with the patient.

Frequent complications that may occur after focal cryotherapy for prostate cancer:

- Acute urinary retention may occur immediately or within 48 hours after the procedure, due to edema related to the cryotherapy (between 2 and 15% of cases)
- Urinary tract infection (between 4 and 17% of cases)

Other complications, in particular urinary fistulas or urethral tears, may occur but are rare (fewer than 3% of cases).

Before the procedure, patients must meet with the interventional radiologist for consultation, in order to ask any questions they may have and address the various issues involved in the prostate cancer treatment.

The morning of the procedure, the patient must have an enema and take an antibiotic for three days.

One month after the procedure, the patient will see the interventional radiologist again for a follow-up MRI to ensure that the tumor is completely gone. The first-line approach to subsequent follow-up will be based on one dose of PSA and an MRI.