How Is Cryotherapy Used for Prostate Cancer?
Cryotherapy, also called cryosurgery or cryoablation, is a non-surgical treatment option that uses freezing cold temperatures to kill cancer cells. Cryotherapy is less invasive than surgery and typically has a shorter recovery process. Cryotherapy may not be as effective when compared to radiation for advanced tumors. Cryotherapy can be used as a primary treatment option for localized prostate cancer, however, it can also be used for recurrent cancer that has not spread beyond the prostate.
What is cryotherapy?
Whole-gland cryotherapy involves killing and destroying cancer cells in the prostate, along with the entirety of the prostate, while newer focal cryotherapy utilizes advancements in procedural tools and technology to target only the specific portion of the prostate gland that contains cancerous cells. Utilizing advanced cryotherapy technologies and techniques is relatively new in the prostate cancer treatment world, and more research needs to be done to determine the current long-term outcomes of the procedure, as well as to determine its efficacy when compared to other treatments.1
How does it affect prostate cancer?
Cryotherapy utilizes freezing gases to cool prostate cancer and prostate gland cells to kill prostate cancer cells. Directly, these cells die as a result of the freezing and thawing process. The cellular components cannot withstand this change in temperature and will die. When cells, including cancer cells, are too damaged to function, they will manually destroy themselves in a process called apoptosis. Indirectly, these cells are further destroyed by changes in the microvascular system surrounding where the procedure was performed, as well as due to inflammation. Since cryotherapy is a localized procedure, it is typically used in localized prostate cancer cases. This localized cancer can be recurrent in some cases, and cryotherapy may be used as a salvage treatment option, or a treatment used when another option, such as radiotherapy, has failed.2-4
The procedure itself
Cryotherapy is performed under anesthesia and can often be performed as an outpatient procedure (meaning the treated individual can go home the same day). The procedure utilizes several needles or hollow probes through the area between the anus and the scrotum. These probes are inserted using transrectal ultrasound (TRUS) guidance, meaning that the physician performing the procedure will use real-time images to make sure the probes are being inserted into the right location. Once inside the body, these images will further guide the probes to make sure the physician is treating the correct location as precisely as possible.
Freezing gas, typically argon gas, is circulated through the probes to freeze the cells that the probes are touching, as well as others nearby. A whole-gland cryotherapy procedure will aim to destroy the entire prostate gland, including the cancer cells, where focal cryotherapy, a newer technique, will aim to treat a small subsection of the prostate where the cancer cells reside. It may be necessary to clear the bowels prior to the procedure using an enema. Additionally, to protect the urethra (the tube that carries urine out of the body) from freezing and losing function, warm salt water is circulated through it via a catheter during the entirety of the procedure. After the procedure, this catheter will typically remain in place for a few weeks, to ensure full emptying of the bladder during recovery.
It is common to have follow-up appointments every few months after the procedure to ensure that the recovery process is going smoothly, to assess for any signs of recurrence, and to address any side effects that have developed. It is not uncommon to have a repeat biopsy of the area within a year after the procedure to further assess for recurrence.1,3,4
Risks and side effects of the procedure
Advancements in ultrasound guidance and other techniques and tools used for this procedure have reduced the occurrence of serious side effects greatly. However, there is still a chance of developing some of the following issues post-procedure:
- Swelling of the procedure area, including the penis or scrotum
- Problems urinating including burning or pain, as well as developing the need to urinate more frequently
- Problems defecating, including developing the need to empty the bowels more frequently
- Urinary incontinence (loss of bladder control)
- Blood in the urine
- Erectile dysfunction
Many of these side effects are linked to the possibility of damaging the neurovascular bundle (NVB) near the procedural area. This is one of the main contributors to erectile dysfunction or sexual dysfunction side effects, however, several studies have reported that these issues may resolve within three years of the procedure. The procedure also carries a small risk (less than 1%) of developing an abnormal connection between the rectum and bladder, called a fistula, which requires surgery to fix. When a fistula develops, urine can leak into the rectum.
Other very rare side effects include injury to the rectum, infection of the pubic bone, or blockage of the urethra. Your doctor will assess your specific case and determine if cryotherapy is right for you, and what side effects you may be at risk for. They also may be able to provide you with information or other medications to combat any debilitating or quality of life altering developments after the procedure.2,4,5
Areas of research
Although cryotherapy as a procedure for cancer has been around for many decades, cryotherapy for prostate cancer, specifically focal cryotherapy, is a newer idea. Further, higher quality image guiding techniques and other advancements in cryotherapy-related tools have led to a decrease in morbidity (medical conditions related to a procedure), however, the longer-term implications of newer forms of cryotherapy are not well documented at this time. Early results have pointed towards similar efficacy and quality of life outcomes of cryotherapy when compared to several other treatment options, however, these results need to be further investigated.
Additionally, determining the changes in side effects and effectiveness of focal cryotherapy over whole-gland cryotherapy needs to be further analyzed as well. Similarly, determining when cryotherapy is most effective and if it should be used in combination with any other treatment options are issues that are still being researched as well.3-7