The United States Preventive Services Task Force has recommended that doctors stop using prostate-specific antigen-based screening to detect prostate cancer in men of any age.
The screening involves a blood test that checks for higher than normal levels of prostate-specific antigen, or PSA, in the blood. A high level of this antigen may signal prostate cancer or be an indication of more benign conditions. According to the task force, a positive PSA test can lead to invasive biopsies and their associated risks, including impotence and incontinence, and it recommended against healthy men undergoing the test.
The US government’s advisory task force, in a report released in May 2012, said there was “convincing evidence that PSA-based screening leads to substantial over-diagnosis of prostate tumours” and that many men are being subjected to the harms of treatment of prostate cancers – biopsies or radiation treatment, for example – that never become symptomatic.
“Even for men whose screen-detected cancer would otherwise have been later identified without screening, most experience the same outcome and are, therefore, subjected to the harms of treatment for a much longer period of time. There is convincing evidence that PSA-based screening for prostate cancer results in considerable over-treatment and its associated harms,” the report stated.
According to Cayman Islands Health Services Authority data, prostate cancer is the most common cancer among men in the Cayman Islands.
The latest recommendations are based mostly on reviews of two large clinical trials of prostate cancer screening that have been published since 2008. The studies showed that the number of men who avoided dying of prostate cancer because of screening after 10 to 14 years was small. In addition, the PSA test often produces false-positive results that lead to more testing, including biopsies, which can have their own side effects, according to the report.
Prostate cancer often grows so slowly that many men who have it detected during screening might never need treatment, the task force noted, pointing out that one of the problems with prostate cancer screening is that it does not determine which prostate cancers are aggressive and need treatment and which are not likely to cause problems.
The task force stated that nearly 90 per cent of men with PSA-detected prostate cancer go on to have surgery, radiation, or hormone therapy. Up to five in 1,000 men will die within one month of surgery, and at least 20 to 30 per cent of men who have surgery or radiation therapy will have serious long-term side effects, such as urinary incontinence, erectile dysfunction, or bowel dysfunction.
Dr. Sook Yin, medical director of the Cayman Islands Cancer Society, said practising urologists in Cayman were looking at the new recommendation with caution.
“The American Medical Association has officially expressed concern over the recent … recommendations as they have concerns that adequate input from specialists in these areas has not been given,” Dr. Yin said.
The American Cancer Society recommends that men make an informed decision with their doctor about whether to be tested for prostate cancer, stating that research has not yet proven that the potential benefits of testing outweigh the harms of testing and treatment.
The American Cancer Society also recommends that, starting at age 50, men should talk to a doctor about the pros and cons of testing, so they can decide if testing is the right choice for them. According to its guidelines, if patients are African-American or have a father or brother who had prostate cancer before age 65, men should have this talk with a doctor starting at age 45. If men decide to be tested, they should have the PSA blood test with or without a rectal exam. How often they are tested will depend on their PSA level.
Dr. Sidney Ebanks, president of the Cayman Island Islands Medical and Dental Society, which is a non-regulatory association of professionals, said PSA screenings should be considered on a case-by-case basis.
“Much like our North American colleagues, it is our viewpoint that medical care, including screening examinations should be individualised, with testing embarked upon in the wake of discussions of pros and cons between the doctor and the patient,” Dr. Ebanks said. “Multiple variables enter into the decision that is ultimately made, however, we are mindful that Afro-Caribbean men have a very high incidence rate of prostate cancer and inherent in discussing screening recommendations, either in support or dissent, the local demographics must be considered.”
Local surgeon Dr. Steve Tomlinson pointed out that a person’s PSA can be elevated as a result of a number of conditions, including when a patient has an inflamed or enlarged prostate and in cases where cancer is present.
He said the task force’s report did not address the percentage difference between what is known as “free” and “bound” PSA proportions. “Free” means the antigen is not attached to a protein in the blood and “bound” means it is attached.
The proportions of free and bound PSA are different in men with prostate cancer, compared to men who have benign prostate disease. It is generally accepted that lower amount of free PSA in a test means a higher chance of cancer, but both free and bound PSA must be checked before that determination can be made.
“If the free PSA is less than 10 per cent, then there is a greater likelihood a person will have prostate cancer,” Dr. Tomlinson said.
He suggested that men as young as in their 30s should consider being screened, so that if a prostate issue arises at a later age, their PSA can be compared to their earlier “normal” baseline reading.
The Cayman Islands Cancer Society’s Dr. Yin pointed out that the US Preventative Services Task Force is the same organisation that recommended that screening mammograms should not be done in the 40-year-old age group in 2009. “This recommendation was rejected by numerous medical bodies and now researchers are saying there is more evidence that yearly mammograms should start at age 40,” Dr. Yin said.
She said the Cayman Islands Cancer Society would continue to bring awareness of prostate cancer to the community. “We will educate the public on the risk factors, signs and symptoms of prostate cancer, highlight controversy of the PSA testing, avail specialists to bring latest development on the advantages and disadvantages of PSA screening, encourage men to discuss with their healthcare providers and make a decision together whether they should get screened,” Dr. Yin said.
She added: “If the decision was made that PSA testing is indicated, then the Cayman Islands Cancer Society will provide vouchers for free PSA testing for those who are not insured or not covered by the medical insurance that they have. CICS will continue with its Movember partners and the Lions Club of Grand Cayman to bring prostate cancer awareness … to all districts in the month of November.”