The topic of using PDE5 inhibitors (PDE5I) to recover sexual function after prostate cancer treatment is an important one. Within six months of having a radical prostatectomy, 85% of men do not respond to PDE5I medication, due to nerve trauma. However, they have an excellent chance of responding after 18 to 24 months. Inversely, men can usually produce erections during the first year after radiation therapy, but they may start developing problems two to four years later. At that time, they may find that PDE5Is don’t work very well for them, because of nerve damage from the radiation.

There are currently three PDE5Is on the market: sildenafil (Viagra®), tadalafil (Cialis®) and vardenafil (Levitra®). Men should start with the maximum strength, as research shows that 44% of people use a suboptimal dose, which leads to failure. A 2004 study conducted by Hellstrom et al determined that the best chance of success with sildenafil 100 mg was achieved after six to eight attempts, whereas with vardenafil 10 mg and tadalafil 20 mg, they required between three and eight tries. In other words, “If at first you don’t succeed, try, try again!” Finally, taking a PDE5I on a once-a-day dosing schedule may sometimes lead to better results in men who were unresponsive when taking the same medication “on-demand.”

Whether you take these medications with or without food is important. While tadalafil is unaffected by food, sildenafil and vardenafil have to be taken on an empty stomach. Taking these two medications after a meal that’s rich in high-fat foods can reduce the dose anywhere from 20% to 50%, resulting in a 32% chance of failure. Also, the high-fat content doubles the time it takes for the medication to be absorbed — from one to two hours. In the case of men who are diabetic, stomach-emptying time is delayed even more, so it’s important to take sildenafil and vardenafil before meals.

In 2005, a study by Hatzichristou found that leaving insufficient time between taking the PDE5I and sexual intercourse resulted in a 22% failure rate. Sildenafil and vardenafil should be taken at least one hour before (remember, on an empty stomach). For first-time users of tadalafil, it may be necessary to try this medication four hours prior to activity, as it can take two to four hours to take effect.

Men experiencing inadequate sexual stimulation accounted for 12% of the failures. As a final piece of advice, it’s important not to “rush” things and to allow for proper stimulation.

 There’s a known genetic tendency for the development of many diseases such as high cholesterol, type 2 diabetes and high blood pressure, but evidence now also identifies genes that are passed from parent to child and increase the risk of developing certain cancers. The study of inherited genetic mutations, or alterations, shows immense promise. Two specific alterations, BRCA1 and BRCA2, have been linked to the increased risk of prostate cancer.

The Breast Cancer 1 (BRCA1) and Breast Cancer 2 (BRCA2) genes were the first to be identified and associated with breast cancer. Everyone has these genes, but it is their alteration that makes them cancer causing. Women with a BRCA mutation have five times the risk of developing breast cancer as other women. Men can carry and pass on these same genetic changes. Men who are carriers of these mutations also have an increased risk of prostate cancer compared to non-carriers, and the risk rises significantly with the number of family members who have been diagnosed with prostate cancer. The overall lifetime chance of prostate cancer for men who carry the BRCA mutated gene is 10%. Within a population of carriers the risk seems quite high, but in fact, the occurrence of these mutations is low — only between 0.06% and 0.26% of the general population.

So, how does this risk impact outcome? The risk of developing prostate cancer is a complex interaction of events; besides heredity, it also includes environmental and lifestyle factors. There is no conclusive molecular pathway that can be specifically correlated to the initiation and progression of the disease. But certain genetic characteristics increase the risk, with family history playing a significant role. While the presence of BRCA1 and BRCA2 gene alterations raise the risk of prostate cancer significantly, genetic testing and counselling are not endorsed, since the occurrence of mutations is low and the emotional and financial cost is high. Individuals and families should discuss their risks with their medical practitioners. Prostate cancer screening guidelines have been developed to help decide on appropriate screening methods.

Adopting a healthy lifestyle remains the cornerstone of all disease prevention strategies, and is encouraged for any family that feels they may be at risk.

 The recent screening trial from Europe helps answer this question. Initially, the study used digital rectal examination (DRE) and transrectal ultrasound as well as PSA, because it wasn’t known which test or combination of tests would give the best cancer pick-up rate. The PSA threshold for taking action was initially a level over 4 ng/mL. The study found that DRE added little to the pick-up rate, and that by dropping the PSA action level to 3 ng/mL and omitting the DRE, similar numbers of cancers were detected. Without a DRE, only 20% of screened men needed a biopsy, compared to 28% with DRE. This resulted in the following advantages: 1) avoiding a lot of unnecessary biopsies; 2) improving the pick-up rate for cancer from 18% to 24% in those who had a biopsy.

One could argue that adding DRE to a PSA threshold of 3 ng/mL would further increase the diagnosis rate. But in fact, the rise would likely only be marginal, and at a cost of again boosting the number of negative (thus unnecessary) biopsies. A good screening strategy should strike a balance between detecting cancer and not causing too much harm from over-investigation of men without cancer.

So, is the DRE dead? Not yet. Certainly, it’s important if you have any rectal bleeding or pain, and it helps determine prostate size for those with benign symptoms. Some authorities still consider it part of their screening recommendations, but the evidence to continue with it is weak. It’s particularly unhelpful when used alone without PSA, with no correlation to biopsy findings.

Being tested puts some guys off in the first place, while others may feel more at ease with it. As for me, I’m happy to forgo the DRE!

As one patient commented prior to submitting to the test: “It sounds so technical and modern, the ‘digital’ rectal examination, but you know what — it isn’t really, is it?”