What considerations should a man keep in mind when talking to his doctor about getting a PSA test to screen for prostate cancer? Dr. Laurence Klotz, surgical oncologist with Sunnybrook’s Odette Genitourinary Cancer Care team, discusses the test’s relative value and trade-offs.
1. PSA Test as a valuable predictor of risk
Though not perfect the PSA test remains one of only a few effective ways available to help calculate individual risk of prostate cancer. Understanding risk goes a long way. 75% of men in their forties with a low PSA,(≤ 1.1) have almost no risk of developing metastatic prostate cancer in the next 25 years, and have no need for a repeat PSA for 5 years. [pullquote align=’right’] The PSA test is a blood test to determine the level of prostate specific antigen or PSA in the blood. Elevated levels of PSA are associated with an increased risk that prostate cancer is present. [/pullquote] A man in his sixties with a low PSA can stop PSA screening because he has almost no risk of dying from the disease. For a man to know he is low-risk is very reassuring, particularly if he has a family history of the disease or has a racial pre-disposition. There is no other marker that can do that. If the PSA level is elevated, this may indicate the presence of prostate cancer. An individual can choose to have a more detailed discussion with his doctor about diagnostic options and how to manage the disease if it is diagnosed. If the disease is aggressive or high-grade, there is a major, potentially life-saving benefit in earlier diagnosis, to initiate treatment plans. If the disease is benign behaving or low-grade, there are now less radical ways to monitor and manage the disease.
2. PSA Test saves lives
Deaths from prostate cancer in Canada have decreased about 40% since PSA was introduced 25 years ago. This is likely partly due to improved treatment but the best data we have suggests that half or more of that mortality reduction is due to early detection of the disease when it is more amenable to cure. Results from the most definitive prospective randomized Phase III trial of screening show on average, a 27% reduction in deaths from prostate cancer in the screened men. Many investigators believe this reduction will increase with longer follow up. What’s more, the frequency of metastatic disease (prostate cancer that has spread) at the time of diagnosis has been reduced by 90%. In screening trials the mortality reduction is at about 25 to 30 % at 13 years of follow-up. This benefit will likely continue to increase over time, because many prostate cancers take 15 to 20 years to be lethal. In the best clinical trial, data shows that for each 12 patients diagnosed after a PSA test, one life is saved.
3. PSA Test should remain a patient’s preference in consultation with his doctor.
For the individual with a high PSA, there are more targeted and image-guided diagnostic tests being developed. Treatment will affect quality of life for both the individual who may have prostate cancer, and for the individual with a low PSA, who may want to reduce his likelihood of dying from the disease. There will be trade-offs, but prostate cancer treatments have become more minimally invasive and better targeted.
4. Reduction of overtreatment being embraced in Canada.
We are managing low PSA or low-grade disease differently now. We are reducing overtreatment or avoiding treatment in about half of the patients who used to be treated. Across Canada, we have embraced Active Surveillance With Selective Delayed Intervention and most patients with low-grade disease are managed with initial conservative therapy.
thank you for sharing this information
I only wish you would have GP doctors educated on the very important factor of psa testing . When I booked a complete physical for my husband in 2009 the nurse practioner never did a Dre exam the box for psa screening was not checked off she deferred test because my husband at 57 “LOOKED HEALTHY” In 2010 there were symptoms that would relate to prostate but that year he was told as men age they get those symtoms. Once again even then the box was not checked off. He had no previous screening , he is a only child, his mother had breast cancer? Dave is now a patient at Sunnybrook with stage 4 metastic prostate cancer. His psa factor is 1,670. Of course this should have been found at a curable stage ! We follow very closely with Prostate Cancer Canada and just recently a urologist at Princess Margaret put down the Canadian Task Force Guidlines. It is about time as stage 4 cancer no matter where it is is Stage 4. And not curable. It makes me very angry that had Dave been given screening we may not be where we are today. Why is there is even a debate about screening. We are fortunate that along the way we have had extrordinary Drs along the cancer journey. We have received the latest advancements in treating the cancer ….BUT IF ONLY IF FOR THE SAKE OF NOT DOING SCREENING! There is no family who would ever want to be where we are.