The newest data says that abandoning PSA screening for prostate cancer would be a huge step backwards, going against the increasingly anti-PSA conversation of late.Trondheim Havn/Flickr
It started in 1987, with the introduction of the prostate-specific antigen (PSA) blood test. Six years later, an Atlantic story on this revolutionary innovation contextualized its importance:
For many in the field the PSA test changed everything. Simple to perform, not hugely expensive, free of embarrassment and discomfort, it seemed to provide doctors with a way to detect prostate trouble early and accurately. If the PSA level jumped, the next step would be a biopsy - a more unpleasant and costly business, but one justified by the potential gravity of the situation. If the biopsy indicated cancer, a surgeon might be called in. The operation, called a radical prostatectomy, removes the prostate and thus the source of the problem. If performed before the carcinoma spreads, surgery is often successful, in that it ends the threat from cancer. But the procedure is dangerous - it may kill up to one out of a hundred patients outright - and fraught with possible side effects, such as impotence and incontinence. Even so, physicians reasoned, quick detection of prostate cancer would save thousands of people from awful deaths every year.
That was 1993, and the optimism of the PSA test's early years was already beginning to wane. The very person responsible for developing the screening procedure, Normal Yang, told The Atlantic that he regretted his own innovation:
"It's gone out of control," he says. "People don't know what they're doing, and it's going to be a terrible mess. I feel sick about it. It's a disaster for the healthcare system - a horrible disaster. We've rushed ahead and created a nightmare."
Since then, the debate over whether PSA screening is helping or hurting has raged, but it continued to be used widely. The test, some have argued, is not accurate enough, and it does nothing to decrease the death rate. The evidence showed that 48 patients would need to undergo radical prostatectomy -- enduring not just the risks of the operation, but the potential subsequent effects -- in order to save one life.
In 2011, the U.S. Preventive Services Task Force definitively recommended against PSA screening in all men.
But they hardly had the final say in the matter. Earlier this month, the American Society of Clinical Oncology weighed in with its own cost-benefit analysis. Although it maintained that general screening should be discouraged, the ASCO recommended that physicians discuss the risks and benefits of the PSA test with men who have a life expectancy of greater than ten years.
Today could end up going down as another turning point in the debate, and a significant one at that. A new study in the journal Cancer, which is published on behalf of the American Cancer Society (which itself is ambivalent about screening for prostate cancer) argues that the test is life-saving after all. In doing so, the article jumps all the way back to the pre-PSA era, comparing data from 1983-1985 to more current reports, and predicting that the number of men with metastatic cancer at the time of diagnosis would be three times as high without early screening. As many as 17,000 cases of this most serious form of prostate cancer, the authors maintain, are prevented each year by the PSA test:
Yes, there are trade-offs associated with the PSA test and many factors influence the disease outcome. And yet our data are very clear: not doing the PSA test will result in many men presenting with far more advanced prostate cancer. And almost all men with metastasis at diagnosis will die from prostate cancer.
The study is observational, and as such cannot tell us definitively whether there is a direct causal relationship between PSA screening and the fewer cases
of metastasis at diagnosis. But in going against what is quickly becoming the new common logic of prostate cancer, it should make experts take pause before turning their backs completely on early screening.