Reports are coming in that an expert panel that advises the US government is set to recommend dropping routine screening for prostate cancer using the prostate specific antigen, or PSA, test.
CNN reports that a draft copy of the US Preventive Services Task Force document due to be released on Monday reveals the group is going to recommend the PSA test be given a “D” rating, which means there is “moderate to high certainty” that the test offers few benefits, or that they are outweighed by the risks and harms.
The announcement, which precedes a consultation period after which the panel will give its final recommendation, is unlikely to surprise cancer specialists, many of whom have the view that screening for prostate cancer using the PSA test isn’t so cut and dried as once thought.
When the test first came in as a routine screening tool for prostate cancer in the 1990s, it was under the assumption that the sooner you detect a cancer the better the chance of treating it before it spreads. But as more studies about the test and the longer term outcomes have emerged, that view has changed.
In a blog first published in June this year and reposted this week in the light of recent developments, Dr Otis Brawley, Chief Medical Officer of the American Cancer Society says that in the US, 1 in 6 men has a lifetime risk of being diagnosed with cancer, compared with 1 in 10 in Western Europe, yet the lifetime risk of dying from prostate cancer is about 1 in 36 in both regions.
“Screening began without the completion of the scientific research to show that it saves lives,” writes Brawley.
“For most advocates of screening and aggressive treatment, there was and is a desire to do something that might be beneficial to the population of men at risk. Unfortunately the history of medicine is filled with examples of physicians ‘jumping the gun’ and using possible interventions before they are properly evaluated,” he adds.
The main problem is that the PSA test does not discriminate between fast growing tumors that kill and tumors that grow very slowly and are unlikely to become aggressive in a man’s lifetime. Also, the test can be positive even when there is no cancer such as when the prostate is enlarged or there is an infection.
So the quandary is that while many men will undergo treatment they don’t need, with potential side-effects that include possible incontinence and impotence, some will undergo treatment that saves their lives.
Brawley says the quandary is well summarized by Dr Willet Whitmore, former chief of urology at Memorial Sloan Kettering Cancer Center, who once said:
“When cure is possible, is it necessary? When cure is necessary, is it possible?”
As more and more studies have been done and questioned the long term benefits of PSA screening for prostate cancer, medical organizations have changed their recommendations about it, such that most of them now leave open the possibility that screening has benefits, but point out that so far, there is more evidence on the harms.
Added to this is is emerging evidence that men worried about receiving a diagnosis of prostate cancer are also at higher risk of depression and suicide.
Dr. Virginia Moyer of the Baylor College of Medicine heads the US Preventive Services Task Force. She told Associated Press on Thursday that they analyzed all the existing evidence, including five significant studies, to find out what effect routine screening for PSA has on prostate cancer deaths. They concluded it was of little if any benefit.
But routine screening itself is harmful, and in some cases leads to deaths from the biopsies, surgery and radiation, said Moyer.
Dr. Kenneth Lin, lead author of the Task Force’s prostate cancer screening guidelines and senior author of the report that is to be released on Monday, said of 100 men over the age of 50 who have a PSA test, 17 will have prostate cancer, of which only 3 will have a fast growing one and die from it.
But, if you treat the 14 men with the slow-growing tumors, they could be at risk of impotence or incontinence, or even death. Approximately one in every 500 men who have a radical prostatectomy dies because of surgery complications, said Lin in a news report from CNN, where he suggests perhaps only men with a “horrible family history where everyone gets prostate cancer before the age of 50,” should have the test, but otherwise, he says, “for most men, testing is harmful”.
Moyer says the Task Force’s recommendation means doctors shouldn’t raise the option with healthy patients, but if they ask for it, and still want it after they have considered the evidence, then they should receive it. Equally, should a man present with prostate symptoms, then it would appropriate to offer him the PSA.
It will be interesting to hear the arguments that will be raised when the recommendation is open for public scrutiny and feedback. The American Cancer Society website carries several comments from patients in support of the test, that can perhaps be summarized in the words of one Mr Evens who says PSA testing and the ensuing treatment probably saved his life, but in his view, the emphasis should not be on the testing itself, but on “the decisions made afterwards about treatment”.
The American Cancer Society estimates that this year nearly quarter of a million men will find out they have prostate cancer and more than 33,700 will die of it. Only lung cancer kills more men through cancer.
Written by Catharine Paddock PhD