Monday, September 5, 2016

Early Prostate Cancer Diagnoses Continue to Fall in U.S.

Diagnoses of early prostate cancer continue to decline in the United States, following the U.S. Preventive Services Task Force recommendation against routine screening for the disease, researchers report.

The screening involves a blood test that identifies levels of PSA (prostatic specific antigen), a protein produced by the prostate gland. That test can determine when cancer exists, but it often wrongly identifies nonexistent cancer.

The “false positive” results can cause anxiety and lead to unnecessary follow-up tests. Because of this, the task force issued a draft recommendation against routine screening in 2011 and a final guideline in 2012.

Since then, diagnoses of early prostate cancer in American men aged 50 and older dropped by 19% between 2011 and 2012 and by another 6% the following year, said lead researcher Dr. Ahmedin Jemal. He is vice president of the American Cancer Society’s surveillance and health services research program.

But while men may have been spare unnecessary anguish, less frequent screening may have a downside. Some experts worry more men will develop potentially fatal prostate cancer as a result.

There is a balance in the task force recommendation, said Dr. Anthony D’Amico, chief of genitourinary radiation oncology at Brigham and Women’s Hospital and the Dana Farber Cancer institute, in Boston.

“Some men who should not be treated are not being diagnosed, but that also means some men who should be treated are either losing the chance for cure or presenting later and needing to undergo more treatment and more side effects for a possible cure,” he said.

The decrease in diagnoses of early-stage prostate cancer may be partly due to misreading of the task force’s recommendation, added Dr. Otis Brawley, the cancer society’s chief medical officer.

“I believe the task force guideline is being misunderstood,” he said. “The key word that is missed is ‘routine’ – the task force does not recommend routine screening. This in my mind means they are not against all screening. Also, they do call for informed decision-making regarding potential risks and potential benefits,” Brawley said.

The main issue is whether this is an early sign that more high-risk disease, more disease that has spread and more deaths from prostate cancer will happen, noted Dr. D’Amico.

“My opinion is that we are probably heading for more high-risk and metastatic disease in the next year or two, followed by more deaths from prostate cancer if the decline in screening is maintained,” D’Amico said.

The latest study was published online Aug. 18 in the journal JAMA Oncology.

My Take:
The PSA does not “determine if cancer exists”, it merely indicates inflammation, usually of the prostate. However, let’s not soft sell the motives of the task force. Urologists were using a minimal rise in the PSA as justification for prostate biopsy, a very lucrative procedure. The side effects from this surgery are numerous and common. There was no need to recommend against the routine running of a PSA. They just need better criteria for justifying prostate biopsy.

I still run a PSA screen on my older male patients every couple of years, more often if it is elevated as BPH (benign prostatic hypertrophy) will slowly elevate the PSA. However, many conditions other than prostate cancer can elevate the PSA - it’s not as specific as you might think. Infections, insect bites and many other factors that increase inflammation in the body can elevate the PSA.

I also believe it is quite possible that many of those diagnosed with early prostate cancer were misdiagnosed. Physicians may not be missing a high percentage of early prostate cancer, they are no longer over diagnosing.

There is a British trial currently ongoing that should publish next year. The study is designed to assess the benefits of PSA testing. Hopefully, the results will shed some light on this issue.

The Bottom Line:
As I noted in 2012 when the task force issued their final guideline, the PSA continues to be an important screening test. However, physicians must not use the results as an excuse to rush to surgery. I will continue to order a PSA when I deem it appropriate.

Source: August 18, 2016 National Institutes of Health

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