Читать книгу Saving Your Sex Life: A Guide for Men With Prostate Cancer - John P. Mulhall - Страница 19

BPH is a very common condition, with more than six million men over 50 years of age suffering from it and symptoms associated with it. The estimate is that these figures are going to double over the next 20 years, largely related to the aging of our population and the increased risk of BPH as we age. As previously mentioned, age is the number one factor associated with the incidence of BPH. Patients between 60 and 69 years of age have a two-fold increased risk of acute urinary retention, and that jumps to a four-fold risk of urinary retention for men over 70 years of age. When the International Prostate Symptoms Score is 8 or greater, there is a two-fold risk of acute urinary retention. Score yourself at the end of this chapter. Men with prostate sizes over 40 grams are three times as likely to have moderate to severe symptoms, twice as likely to be bothered by these symptoms and twice as likely to experience interference with normal daily activities.

In a very large study known as the MTOPS (Medical Treatment of Prostate Symptoms) study, finasteride was associated with a 34% reduction in risk for progression of BPH, doxazosin, an alpha-blocker, was associated with a 39% reduction in risk of BPH progression, and the combination of doxazosin and finasteride was associated with 67% reduction in risk for BPH progression. Previously it was thought that men with BPH/LUTS had erectile dysfunction because BPH typically occurred in older men, and older men are likely to have conditions such as high blood pressure, high cholesterol and coronary artery disease, or to have undergone radical prostate surgery, and therefore, it was believed that age was the real link. However, it has now been shown in several medical studies that LUTS is an age-independent risk factor for the development of erectile dysfunction.

Table 4 • Incidence Of ED in men with and without LUTS (Modified after Braun, et. al.)

A large study from Cologne, Germany, showed that for each decade of life over 30 years of age, men who had LUTS had a two-fold higher incidence of erectile dysfunction than men who did not have LUTS (Table 4). Another very large study called the MSAM-7 study demonstrated that there was both an age and severity of LUTS relationship. That is, that the older men were and the more severe their lower urinary tract symptoms, the more likely they were to have erectile problems.

It is not fully understood exactly why lower urinary tract symptoms are associated with the development of erectile dysfunction. There is no doubt that men who have severe LUTS have a significant interference with their quality of life. Imagine a man who has to get out of bed five times every night. His sleep deprivation will be such that he will have a significant reduction in his quality of his sleep. It is well known that anything that reduces life satisfaction may, in fact, impact negatively upon erectile function. Much animal and human research is ongoing at the moment which demonstrates that BPH-associated LUTS is a cause for sympathetic nervous system hyperactivity. The autonomic (involuntary) nerves are combined sympathetic and parasympathetic. Sympathetic nerve fibers transmit signals which result in a variety of bodily functions including stress-related symptoms.This increased sympathetic nerve discharge may be a factor in why men have urgency and frequency of urination during the day time. If a state of sympathetic over-activity is present, this is well known to be associated with erection problems as sympathetic nerve fibers are anti-erection. While other theories exist, it is not yet fully understood how LUTS results in erectile dysfunction.

So for the 45–year-old man who has no medical conditions other than BPH and the LUTS associated with it, he is at increased risk for the development of erectile dysfunction. In men with LUTS, the increased risk of erection problems developing is somewhere in the range of 2– to 11–fold, depending on the severity of the lower urinary tract symptoms. Interestingly, it is now understood that the enzyme PDE5 (see later for the story about PDE5 inhibitors) is present within the prostate. PDE5 inhibitors are a class of drugs that includes Viagra, Levitra and Cialis, and it has now been shown that all three drugs not only result in improved erections in many men, but also improved urinary function in men with BPH/LUTS. While these drugs are not yet approved for the treatment of LUTS, it is likely that sometime in the future, one of these drugs will be or that the newer PDE5 inhibitors coming down the road will be used as a medical treatment for BPH.

It is my practice in men who present with the complaint of erectile dysfunction who also have an elevated International Prostate Symptom Scores to inform them that they may not only see improvement in their erectile function but also in their urinary symptoms when using a Viagra-like medication. There are now some physicians in the country who are exploring the use of Viagra, Levitra and Cialis in patients with LUTS without erectile problems, for the purpose of urinary symptom improvement.