What is Cryotherapy for Prostate Cancer?

What is Cryotherapy?

Cryotherapy (or cryosurgery) is the destruction of diseased cells by freezing and can be used to treat prostate cancer. This is achieved using nitrogen or argon gases cooled to very low temperatures, which are administered to the prostate through metal tubes. The procedure can be carried out under local or general anesthetic. Cryotherapy is an ablative technique, a group of therapies that also include high intensity focused ultrasound and photodynamic therapy.

When is Cryotherapy for Prostate Cancer done?

At present cryotherapy is not a routine treatment for prostate cancer in most European countries and other treatments such as surgery, chemotherapy, radiotherapy or hormone therapy are preferred. This is because cryotherapy has a lower success rate and generally results in greater side-effects such as loss of bladder control and impotence. However, The American Urological Association recently stated that cryotherapy may have a use, particularly in cases where the disease is confined to the prostate.

Prostate Cancer ‘Watchful Waiting’ Surveillance, Radical Therapy and Focal Therapy

In recent years there has been increased screening for prostate cancer by measurement of PSA (prostate specific antigen) levels in the blood, allowing early detection of the disease. As a result, clinicians are seeing more patients with so called intermediate-risk prostate cancer i.e. disease that has not yet spread beyond the prostate.

In cases of intermediate-risk disease, the choice is whether to treat radically or take a ‘watchful waiting’ surveillance approach. Both of these have drawbacks; radical surgery (prostate removal) has side effects such as genitourinary or rectal dysfunction. However the surveillance approach carries the risk of the disease progressing. Both approaches therefore, can cause considerable psychological burden on the patient.

Focal therapy aims to take a midway course between the radical and surveillance approaches by killing the tumor tissue and only a small margin of normal tissue. By preserving as much of the healthy tissue as possible, side effects can be minimized. Some oncologists believe that cryotherapy has potential here, however, it can be difficult to identify which areas of the prostate are affected and hence where to target the therapy.

Research into Cryotherapy for Prostate Cancer

Improved treatments for this disease are still needed, and many prostate cancer clinical trials are ongoing. Cryotherapy is often performed within the context of a clinical trial, being used as salvage therapy to treat disease that has recurred after another treatment.

A recent study by the MD Anderson Cancer Centre in Texas looked at patients with prostate cancer that had recurred after radiotherapy. They compared the effectiveness of two different salvage therapies; radical surgery (removal of the prostate) and cryotherapy. It was found that patients in the surgical group survived longer than those treated with cryotherapy.

Prostate cancer is slow growing compared to many other cancers, sometimes taking many years to progress. Therefore, assessments on the effectiveness of new therapies must follow the progress of patients for at least ten years before definite conclusions can be made.

References

Cancer Research UK www.cancerhelp.org.uk/about-cancer/cancer-questions/cryotherapy-for-prostate-cancer

Locally Recurrent Prostate Cancer after initial Radiation Therapy. L.L. Pisters et al. The Journal of Urology, 182, 2 (Aug 2009)

Is Focal Therapy the Future for Prostate Cancer? Future Oncology, Feb 2010 vol 6, No.2 P261-268