The guidelines, published Tuesday in the journal JAMA, come from the US Preventive Services Task Force, an independent panel of experts that makes recommendations to the American public about preventive services. They are an update to previous guidelines published in 2012 that recommended against routine screening due to the risks involved in additional testing and treatment.
But according to new research, prostate-specific antigen (PSA)-based screening for men in the 55 to 69 age group could prevent 1.3 deaths and 3 cases of cancer metastases for every 1,000 men screened. Therefore, the task force concluded that screening does make sense for men in that age group, but that they should be aware of the potential risks associated with additional testing.
“Previously, we recommended against routine screening for prostate cancer,” said Dr. Alex Krist, vice-chairman for the US Preventive Services Task Force. “Now, we’re recommending that men aged 55 to 69 who are considering prostate cancer screening talk with their doctor about both the benefits and the harms of prostate cancer screening and have an opportunity to weigh their values in the decision.”
Benefits of prostate cancer screening can include identifying and treating a potentially lethal disease. Risks include the possible side effects of further diagnostic tests and treatment such as incontinence and erectile dysfunction, as well as the psychological effects of a false diagnosis.
These screening guidelines are for people who do not have typical symptoms of prostate cancer such as trouble urinating, blood in the semen or pelvic discomfort. People with these symptoms should see their healthcare provider regardless, according to the Mayo Clinic.
The reason behind the recent update comes from new research highlighting the benefits of prostate cancer screening, according to Krist.
“When we looked at the evidence now, we found that a few men who choose to be screened will benefit from screening. About one in 1,000 won’t die from prostate cancer, and about three in 1,000 won’t get metastatic disease,” Krist said.
“But we also know that many more men will get harmed (from screening). About 240 will have a high PSA, and only about 100 of these will actually be diagnosed with prostate cancer.”
According to the task force, this means all men in the 55 to 69 age group should have a thorough and individualized conversation with their health care providers about the risks and benefits of prostate cancer screening and their willingness to undergo additional testing.
“One of the ways doctors can help facilitate that process is to provide patients with decision-making aids — and those can be written or web-based information that really outlines the pros and cons of the various alternatives,” said Dr. Richard Hoffman, director of the Division of Internal Medicine at the University of Iowa Carver College of Medicine, who was not involved in the new report.
“If people are going to buy a car or a flat-screen TV, they’re going to do their research, and they’re going to compare options,” Hoffman added. “And it really should be that way for cancer screening. These really are more important decisions, and we would like people to educate themselves before they have these discussions.”
The newest guidelines also apply to those men at highest risk of prostate cancer, such as African-American men and those with a family history of the disease. Men in these two groups may want to be even more diligent about getting screened, according to Krist.
“We know that African-American men are twice as likely to get prostate cancer, and they’re twice as likely to die from prostate cancer,” Krist said.
In one of the studies that helped guide the task force, only a small portion of the sample was African-American, “so we weren’t really able to say whether they had better outcomes from screening,” Krist added. “But men aged 55 to 69 should talk to their doctor, and if they’re high risk, that should be part of the conversation, too.”
According to the American Cancer Society, the likelihood of an African-American man developing prostate cancer in his lifetime is 18%, compared to 13% for Caucasian men. Approximately 4.4% of African American men and 2.4% of Caucasian men will ultimately die from prostate cancer.
But for men 70 or older, the task force did not recommend PSA-based prostate cancer screening due to the higher likelihood of false positive results and additional risks associated with further diagnostic tests and treatments.
“As men age, they have a higher risk of false positives, and they also have more complications with biopsies and treatments such as surgery or radiation. So that changes the balance of benefits and harms so that, at 70 years and above, men aren’t likely to benefit from screening,” Krist said.
The prostate is a gland in the male reproductive system that produces the fluid found in semen. Prostate cancer refers to the unrestrained growth of certain cells in the gland. The rate of growth varies dramatically between patients: In some, the tumors grow slowly and are unlikely to spread, while in others, they grow rapidly and are life-threatening.
Prostate cancer is the second most common cancer in men, after skin cancer. The lifetime risk of being diagnosed with prostate cancer for men in the US is approximately 13%, according to the American Cancer Society.
Screening for prostate cancer is typically done by testing for the PSA protein that is produced by the cancer cells.
Medicare currently covers prostate cancer screening tests once a year for all men age 50 and over. Most states also have laws assuring that private health insurers cover these tests, according to the American Cancer Society.
But the PSA screening test is not ideal. PSA is also found in high quantities in other conditions such as benign prostatic hypertrophy and prostatitis, meaning the test is not very specific for cancer.
Consequently, more than half of those men with an elevated prostate-specific antigen do not actually have cancer, according to Hoffman.
“If you use the PSA cut-off of 4 (nanograms per milliliter), probably about 70% of the time, when the man goes to biopsy, he doesn’t have prostate cancer,” he said.
But in some cases, prostate-cancer screening saves lives.
“There’s a European study that’s been tracking men who’ve been screened now for 13 years. And it’s shown that the benefit increases over time. It sounds small, but for every 780 men who get screened, you prevent one prostate cancer death,” Hoffman said.
For those who choose to undergo prostate cancer screening, the task force recommends getting screened no more than once every two to four years.
In a 2014 study, “we saw benefit when men were getting screened every two to four years. So I think it’s reasonable for men who are considering screening to talk to their doctor about this every two to four years,” Krist said. “There’s not a lot of evidence to do this every year. I think every year might increase the risk of harms without incremental benefit.”
Researchers also hope to develop new screening tests that can better identify those cases of prostate cancer that may be life-threatening, according to Hoffman.
“There are a number of other tests. There’s also now some interest in looking at genomic tests, but the problem is that none of these have really been subject to rigorous clinical trials, so we really don’t know,” Hoffman said.