Sunday, October 20, 2019

Update on Prostate Cancer and Cryotherapy

The prostate gland is a walnut-sized gland that is attached to the bottom of the bladder deep in the male pelvis. The prostate gland wraps around the male urethra as it arises from the bladder, and several ducts that run between the prostate gland and the urethra allow the prostatic secretions to be expelled into the urethra at the time of ejaculation. These prostatic secretions, which constitute about 20 percent of the volume of semen, help to create the optimal chemical environment for sperm to thrive and migrate within the female genital tract, thereby enhancing sperm function.
Prostate cancer is the most common non-skin cancer that occurs in men, and the second most common cause of cancer death in men. In 2009, an estimated 192,000 new cases of prostate cancer will be diagnosed, and approximately 27,000 men will die of this disease. Prostate cancer afflicts 1 out of every 6 American men during their lifetimes, and accounts for 25 percent of all cancer diagnoses in men (similar to the percentage of breast cancer cases among all cancer cases diagnosed in women). As with the great majority of breast cancer cases, most prostate cancers appear to be stimulated to grow and spread by sex hormones produced by the gonads (and, specifically, by testosterone and other androgens produced by the testes, and by other tissues in the body).

Almost exactly a year ago, I wrote about the emergence of cryoablation as a treatment for prostate cancer (Cryoablation and Prostate Cancer). Cryoablation uses slender probes to freeze tumors and surrounding normal tissue, and has been proposed as an alternative to surgery or radiation therapy for the treatment of prostate cancer. In July of 2008, I noted that, in most respects, cryoablation appeared to compare favorably with surgery and radiation therapy, although the incidence of impotence appeared to be much higher with cryoablation than with standard prostate cancer treatments. I also noted, at the time, that there was no prospective, randomized clinical research data available with which to make a credible and direct comparison between cryoablation and other more established treatments for prostate cancer. Now, a new prospective, randomized clinical research trial comparing cryoablation with radiation therapy has reported its early results in the journal Cancer.
In this Canadian study, 244 men with newly diagnosed prostate cancer localized to the prostate gland were randomly assigned to undergo either standard external beam radiation treatment or cyroablation. These volunteers with prostate cancer were then followed for 3 years after completing their treatment. Because it is still too early to draw conclusions about cancer recurrence and survival in this group of prostate cancer patients, this preliminary report addresses quality-of-life issues related to these two forms of cancer therapy.

The men who underwent cryoablation reported more difficulties with urination than the men who were treated with radiation early after treatment, although these symptoms resolved over time. The cryotherapy group also reported significantly higher rates of long-term impotence when compared with the men who received radiation therapy. In fact, 3 years after treatment, there was a 13 percent greater incidence of moderate-to-severe sexual dysfunction among the cryotherapy group of men when compared to the radiation therapy group.

The preliminary results of this prospective, randomized clinical research trial suggest that the main long-term quality-of-life difference between cryotherapy and radiation therapy is a significantly greater incidence of long-term sexual dysfunction following cryotherapy.
As I concluded in my last update of cryotherapy for prostate cancer treatment, one year ago, the long-term benefits and risks of this form of treatment are not fully understood at this time, as we lack mature long-term prospective, randomized clinical research data with which to make prudent decisions about this treatment modality. Aside from a higher incidence of sexual dysfunction following cryotherapy, it is still too soon to tell if the long-term survival outcomes with cryotherapy will compare favorably with radiation therapy and surgery. Therefore, for now, I can only recommend cryotherapy for prostate cancer if it is performed within an approved clinical research trial. Stay tuned for further updates on this topic as they become available.
Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and a Surgical Oncologist at the Kaiser Permanente healthcare system in Orange County, California

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Update on Prostate Cancer and Cryotherapy
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