General · 16th February 2015
The prostate is a small, walnut shaped gland, located below the bladder and in front of the rectum in men. The prostate surrounds part of the urethra, which carries urine from the bladder. The prostate gland creates fluid that carries sperm during ejaculation.
The most common prostate related problems are; age related prostate enlargement (benign prostatic hypertrophy: BPH), inflammation of the prostate (prostatitis), and prostate cancer.
Prostate cancer is the leading cause of non-skin cancers among Canadian men. It is the third leading cause of death. According to Canadian Cancer society data, in 2014, 236,000 men were diagnosed with prostate cancer. Of these, 4,000 (10% of all cancer deaths in men) will die from the disease. On average, this represents 65 Canadian men diagnosed daily. Based on 2009 data, one in eight Canadian men will be expected to develop prostate cancer during their life-time; of these, one in twenty-eight will die from it.
A prostate cancer diagnosis is very rare in men under the age of 40. Men under the age of 50 have a 1 in 1,667 chance of developing prostate cancer in the next five years as opposed to men over the age of 80, who have a 1 in 23 chance. Autopsies done on men over the age of 80 suggests that 80% of men are affected by prostate cancer. Genetics and familial disposition plays a role in risk. Familial disposition may be responsible for 5-10% of those diagnosed. It also presents earlier in those with a family history. Race also constitutes a risk factor. African-American men are most at risk followed by men who are White or Hispanic. Asian men possess the lowest risk. As a result, prostate cancer rates vary by country, though interestingly, prostate cancer found on autopsy is the same throughout the world.
Other risk factors for prostate cancer include smoking, obesity, and environmental factors that are as yet to be determined. Migration data tells us that men immigrating from countries with a low rate of prostate cancer to countries with a high rate of prostate cancer are more at risk, which may suggest some overlap with diet. Of note, men diagnosed with prostate cancer also seem to be at higher risk for melanomas (skin cancer).
Unfortunately, there are few symptoms that suggest prostate cancer in the early stages. Most men are asymptomatic upon diagnosis. Changes that can indicate a problem include voiding difficulties including difficulty initiating a urine stream, urgency, pain with urination, dribbling following urination, a weak stream, inability to empty ones bladder with frequent return to the toilet, blood in urine, and/or pain with ejaculation. Men with these symptoms warrant further investigation, more likely related to prostatitis or BPH. Advanced disease may be picked up when men report bone pain, as metastatic prostate cancer readily attacks bone. Other symptoms include weight loss, loss of appetite, anemia, lower leg pain and swelling.
There are two ways to screen for prostate cancer in asymptomatic men. One is a blood test called prostate specific antigen or PSA. PSA is a protein produced only by the prostate; high levels can indicate cancer activity. Unfortunately PSA can be elevated due to other reasons such as BPH or inflammation. At this time, use of PSA testing alone is controversial. The other way to test for prostate cancer is through the use of the digital rectal exam (DRE). Although simple, this test is not particularly effective. Used alone, it can miss 50% of cancers. At present, combining the DRE and PSA is the most effective means of screening. The chance that a man with a normal PSA and DRE has a significant prostate cancer is low. Even with an abnormal PSA and DRE, there is still only a 50% chance that a cancer will be found.
If a PSA reading is higher than expected, or the DRE is abnormal, then a prostate biopsy is often recommended. This affords a more definitive diagnosis and allows for disease staging. This is a surgical procedure where a needle is inserted into the prostate through the front wall of the rectum that can take fragments of the prostate that can be examined under the microscope. As with any surgical procedure there are associated risks.
All prostate cancers are unique and depend on an individual’s age, health and the type of cancer diagnosed. If diagnosed early, or if the cancer is confined to the prostate alone, chance of cure is high. Treatment choices include surgery (complete removal of the prostate), radiotherapy, or hormone therapy. Unfortunately, it can be difficult to determine which cancers are aggressive and which are not. Prostate cancer restricted to the prostate alone can grow very slowly. This means that some individuals may be treated for a condition that may never affect them in their lifetime. Another treatment that is gaining more and more favour is watchful waiting, whereby testing is conducted at regular intervals to see if the cancer is advancing.
Given the inadequacy of accurately diagnosing cancer, as well as the fact that many prostate cancers grow slowly, many agencies now recommend against screening as they believe the potential harms outweigh the benefits. The Canadian Task Force on Preventative Health is one such agency. According to their data, screening will prevent only one man out of 1,000 from dying of prostate cancer. On the other hand, most men who have an elevated PSA will undergo a prostate biopsy. 178 men out of every 1,000 will undergo an unnecessary biopsy to show that they do not have prostate cancer. Of these, 21 out of the 1,000 will have complications severe enough to require hospitalization. 2 of these will die from their complications.
Of those diagnosed with prostate cancer through screening, 50% are unlikely to cause symptoms, illness or death. However, given the uncertainty regarding progression, most men will choose treatment. Any treatment has risks and benefits. According to the Canadian Task Force, for every 1,000 men receiving treatment, 114-214 will experience short term complications, additional surgeries and blood transfusions, 127-442 will experience long-term erectile dysfunction, up to 178 will experience long-term urinary incontinence and 4-5 will die from complications.
Although the current screening tools are lacking, there is current work ongoing towards a new screening test for prostate cancer that shows great promise.
Other research is looking at using PSA to further differentiate those at high risk from those at low risk. A group in Sweden (BMJ 2014) looked at PSA levels for men at age 60 as predictors of future cancer. What they found was that for those men with a PSA level 2 ng/ml were at high risk for death; 23 men needed to be screened and six diagnosed to prevent one cancer death. In the study, 75% of those screened fell in the groups of PSA’s
As always, it is highly recommended that men over the age of 50 have a conversation with their health practitioner regarding their specific concerns and risks. I believe it is a conversation worth having.