Therapy Lets Prostate Cancer Patients Avoid Erectile Dysfunction

Erectile dysfunction or impotence among men without prostate cancer is most commonly caused by a problem in the blood vessels.Erectile Dysfunction and Prostate Cancer

Researchers at the University of Michigan Comprehensive Cancer Center are using innovative planning techniques to help men with prostate cancer avoid erectile dysfunction after radiation treatment.

By using MRI scans in addition to CT scans, radiation oncologists can identify the blood vessels that control erectile function and plan treatment to target the prostate more precisely, sparing those nearby vessels. Results from an initial study with 25 patients appear in the January issue of the International Journal of Radiation Oncology Biology Physics.

Some 230,000 men were diagnosed with prostate cancer in 2004. While it’s more common in older men, a growing number of men are being diagnosed in their 50s.

“As we treat younger men, erectile function is an important concern. We’re often treating men in their 50s, and this is a very important issue for them. Most of the men I see are going to be cured. Once you start curing cancers at an extremely high rate, then the focus moves to quality of life,” says Patrick W. McLaughlin, M.D., clinical professor of Radiation Oncology at the University of Michigan Medical School and director of Providence Hospital Radiation Oncology, with cancer centers in Southfield and Novi, both affiliated with the U-M Comprehensive Cancer Center.

Treatment for prostate cancer can involve surgery to remove the prostate or radiation therapy. During surgery, the nerves that control erectile function may be severed – which has led to new surgical techniques to avoid cutting those nerves.

But doctors are less sure what causes erectile dysfunction after radiation therapy. Erectile dysfunction among men without prostate cancer is most commonly caused by a problem in the blood vessels, and doctors do know that radiation causes obstruction of the vessels that fall within the treatment area. Using that as a starting point, the U-M team began investigating radiation-related erectile dysfunction as a blood vessel problem.

Typically, radiation oncologists rely on a CT scan to identify the prostate and plan treatment. But because of limitations in the CT scan, the images do not show the bottom of the prostate. Doctors instead estimate where the prostate ends, based on average distance from identifiable structures. The U-M study, using MRI in addition to CT scans to get a better picture of the whole prostate, found the distance between the prostate and the penile bulb ranged from 0.5 cm to 2.0 cm.

“We condemned one of the common tricks people try to use. By assuming an average distance of 1.5 cm between the prostate and the penile bulb, either you’re going to treat way more than you need to or you’re going to miss the prostate,” McLaughlin says.

By taking the additional imaging, the U-M team was able to plan treatment to include the entire prostate but avoid the critical blood vessels below. Preliminary results suggest that avoiding the vessels prevents erectile dysfunction.

“Because we can’t see any detail of this area on CT scans, we just assume if we treat below the prostate it’s no big deal. But it is a big deal. There is no cancer below the prostate, but there are critical structures related to erectile function as well as urine sphincter function. Treating below the prostate may result in needless problems,” McLaughlin says. “I don’t have much doubt from what I’ve seen that this approach is likely to have huge impact.”

About one in two men who undergoes radiation therapy for prostate cancer is unable to have sex five years later unless Viagra or similar medications are used.

In addition, the vessels involved in erectile function also play a role in bowel and bladder control. The researchers suspect avoiding radiation to these areas will improve other quality of life issues, such as urinary leakage and bowel problems.

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Erectile Dysfunction Common in Primary Care Patients

Erectile Dysfunction

A third study of Canadian men visiting primary care physicians indicates that about half of them report having erectile dysfunction, and that it is linked with cardiovascular disease, diabetes, future heart disease risk and increased fasting blood sugar levels.

“Primary care physicians are uniquely positioned to inquire about a patient’s sexual function during a routine office visit,” the authors write. “They can also screen for modifiable risk factors and treatable comorbidities. However, there is little information available regarding the prevalence of� � erectile dysfunction among patients seen in this clinical setting.”

Steven A. Grover, M.D., M.P.A., F.R.C.P.C., Montreal General Hospital and McGill University, Montreal, Quebec, and colleagues surveyed 3,921 men aged 40 to 88 years who visited one of 75 primary care physicians between July 20, 2001, and Nov. 13, 2002. Participants gave medical histories and received physical examinations, including measurements of fasting blood sugar and lipid levels.

Almost half (49.4 percent) of the men reported ED during the previous four weeks or were taking medication for erectile dysfunction, the authors report. Men with cardiovascular disease and diabetes were most likely to have erectile dysfunction. Among men without cardiovascular disease or diabetes, the calculated future risk of developing these conditions was linked to likelihood of having erectile dysfunction. “These data demonstrate that primary care physicians may find that taking a sexual history provides important clinical information beyond the detection of erectile dysfunction,” the authors conclude. (Arch Intern Med. 2006;166:213-219)

Erectile Dysfunction Drugs Affect Other Systems

Treating erectile dysfunction

Since the Food and Drug Administration gave Viagra� � (sildenafil) its approval in 1998, “erectile dysfunction” has become a household term � � � � � � � �” probably to the chagrin of many parents fielding questions from their kids watching TV. But with sildenafil and the subsequent introduction and marketing of Levitra� � (vardenafil) and Cialis� � (tadalafil), many men have found answers to a once-unmentionable condition.

“As more and more patients seek therapy for sexual dysfunction, it is increasingly important for clinicians in a wide range of specialties to become proficient in the mechanisms and systemic effects of these medications,” said Ernst R. Schwarz, M.D., Ph.D., a cardiologist at Cedars-Sinai Medical Center who specializes in therapies for men who suffer from erectile dysfunction (ED) and have heart problems, diabetes, high blood pressure or other related conditions.

Schwarz and colleagues recently concluded a review of the medical literature, as well as their own research findings and clinical data, to determine what actually is known about the effects of long-term use of this class of drugs on various organ systems. Their findings appears in the June 8, 2006 issue of the International Journal of Impotence Research.

Studies so far suggest the drugs, called phosphodiesterase-5 inhibitors (PDE-5i), produce mostly beneficial results, and not just for erectile dysfunction. The FDA recently approved a reformulation of sildenafil for the treatment of primary pulmonary hypertension, a disease that tends to occur in young women, causing elevated blood pressures in the lung that can lead to heart failure and early death.

“When we look at all the different organ systems� � – the blood, the heart, the lungs, blood flow in the brain � � � � � � � �” there are hardly any negative side effects. In fact, just the opposite is true. There are beneficial effects for primary pulmonary hypertension, as well as for conditions such as heart failure and lack of oxygen in the heart,” said Schwarz. “The only issue is that the data we have are from relatively short-term studies. Viagra has been on the market since 1998 and the other two PDE-5 inhibitors were approved by the FDA in 2003. Therefore, we do not have multi-year follow-up studies. On the other hand, the drugs have been on the market for several years now and there have been no reports of negative long-term effects.”

While there are some differences among the three medications, they have many properties in common and work by limiting the activity of the enzyme phosphodiesterase-5, which is found in tissues and vessels of the penis, blood platelets, and smooth muscle of blood vessels. For the treatment of erectile dysfunction, the drugs’ constraint of the enzyme’s action results in increased levels of cyclic guanosine monophosphate (cGMP) and nitric oxide (NO), biochemicals that promote smooth muscle relaxation and increased blood flow in erectile tissue.

According to the article, PDE-5 inhibitors can be effective in treating erectile dysfunction even for many men who also have diabetes, those who are older, and those who have co-existing ischemic heart disease (reduced blood flow to the heart caused by plaque buildup in the arteries). Furthermore, say the authors, “since PDE-5 is found in smooth muscles of the systemic arteries and veins throughout the body, use of PDE-5i has been associated with various cardiovascular effects.”

“The original intention was to develop PDE-5 inhibitors as a treatment for angina, chest pain that occurs when the heart is starved for oxygen,” Schwarz said. “As such, their effects on the heart appear to be all beneficial. Nitrates and other substances commonly used to improve blood flow and oxygenation to the heart muscle have a side effect that we call the ‘steal phenomenon,’ in which blood is taken away from underperfused (flow-restricted) areas to improve blood flow in normal areas. In contrast, PDE-5 inhibitors actually improve blood flow even in areas where there is a blockage of an artery, thereby having a protective effect on the heart muscle.”

The drugs’ potential impact on visual function became a matter of controversy when a suspected link between PDE-5 inhibitors and vision loss led to lawsuits filed last year against the maker of Viagra. According to the article’s authors, however, “analysis of clinical trial data in more than 13,000 men and on more than 35,000 patient-years of observation” found occurrence of the visual disorder to be similar to that of the general population. “Even though individual cases have been reported for all PDE-5i, these recently published data do not suggest an increased incidence of NAION (non-arteric anterior ischemic optic neuropathy) in men who took PDE-5i for erectile dysfunction,” the article states.

ErecAid Supplemental: Effective Erectile Dysfunction Treatment

Plethora Solutions Holdings PLC (“Plethora”, AIM: PLE), the specialist developer of products for the treatment and management of urological disorders, announces results of a study confirming the role its product, ErecAid, as a supplemental first line treatment for erectile dysfunction (ED). ErecAid is marketed through Plethora’s US subsidiary, Timm Medical Technologies, Inc. (“Timm Medical”, Minneapolis, MN).

The phosphodiesterase five inhibitors (PDE5i) such as Viagra and Cialis have become a major resource in the management of ED. Unfortunately, 30-50% of men report inadequate results with these oral medications. When patients fail to respond to the oral medications, physicians are often forced to consider more invasive and more complicated second line agents such as penile injections or urethral suppositories.

New data from a multi-center clinical trial led by investigators at Johns Hopkins School of Medicine demonstrate that use of the ErecAid vacuum erection device to augment PDE5i therapy can greatly improve patient satisfaction. Results of the study were presented at a recent North Central Sectional meeting of the American Urological Association.

Investigators at four separate study sites evaluated 69 men aged 36 to 82 with ED of diverse etiology who had responded inadequately to PDE5i therapy. Study subjects were allowed to continue use of PDE5i’s but were instructed to use the ErecAid device as an adjunct to their current oral medication. Study subjects were assessed using three validated measurements of erectile function and sexual satisfaction: the International Index of Erectile Function (IIEF-5), the Sexual Encounter Profile (SEP-2 and SEP-3) and the Global Patient Assessment Scale (GAPS).

After 4 weeks of supplemental treatment with ErecAid, the IIEF-5 score improved substantially from a baseline of 9.0 to 17.6 (p<0.001). Moreover, of the 34 subjects unable to achieve an erection satisfactory for intercourse at baseline (SEP-2 response of “no”), 27 subjects (79%) reported erections satisfactory for intercourse following the addition of ErecAid (p<0.001). Finally, of 42 subjects reporting no or slight response to PDE5i at baseline (GAPS responses of “not at all” or “slightly”), 31 (74%) reported moderate or great improvement (GAPS responses of “moderately” or “greatly”) at the end of the 4 week study (p<0.001).

According to Dr. Arthur Burnett, Professor of Urology at Johns Hopkins School of Medicine and the lead investigator of this trial, “This study confirms an earlier trial that many patients can achieve excellent results using ErecAid as an addition to oral PDE5i therapy. Based upon these results, I would encourage physicians treating ED to consider the importance of this approach in their treatment protocols and to discuss this option with their patients.”

Hope For Erectile Dysfunction Through Research

Impotence and Erectile Dysfunction Research

Advances in suppositories, injectable medications, implants, and vacuum devices have expanded the options for men seeking treatment for ED. These advances have also helped increase the number of men seeking treatment. Gene therapy for ED is now being tested in several centers and may offer a long-lasting therapeutic approach for ED.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) sponsors programs aimed at understanding the causes of erectile dysfunction and finding treatments to reverse its effects. NIDDK’s Division of Kidney, Urologic, and Hematologic Diseases supported the researchers who developed Viagra and continue to support basic research into the mechanisms of erection and the diseases that impair normal function at the cellular and molecular levels, including diabetes and high blood pressure.

Points to Remember

  • Erectile dysfunction (ED) is the repeated inability to get or keep an erection firm enough for sexual intercourse.
  • Erectile dysfunction� � affects 15 to 30 million American men.
  • Erectile dysfunction� � usually has a physical cause.
  • Erectile dysfunction� � is treatable at all ages.
  • Treatments include psychotherapy, drug therapy, vacuum devices, and surgery.

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