Actor Ben Stiller Adds to PSA Drama

An Argument for a Midlife Baseline Test?

Nick Mulcahy

October 07, 2016

The 48-year-old American actor Ben Stiller's announcement this week that he was treated for prostate cancer and that prostate-specific antigen (PSA) testing "saved my life" has reignited debate over the usefulness of this cancer screening.

In an online essay and in a radio interview, Stiller urged men to undergo the blood-based, prostate-cancer screening, starting with a baseline test when they're in their 40s.

Stiller's celebrity status caused his story to be quickly disseminated into mainstream media, stirring varying commentary about PSA testing.

In the debate, some prominent urologists are calling for a return of PSA testing and are advocating for the strategy of a midlife baseline test (such as Stiller's), whereas other physicians are reminding the public of the test's shortcomings and harms.

However, the expert commentators all seem to agree that it is extremely difficult to say whether or not PSA testing has saved an individual's life ― which is part of the drama of Stiller's story.

Ben Stiller

"It is nearly always impossible in the individual patient to say whether early diagnosis and treatment...was lifesaving or overtreatment," said Stephen Freedland, MD, a urologist at the Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, in Los Angeles, California.

"What we do know is that, on the population level, getting a PSA test done at age 55 and then periodically afterwards can reduce the [relative] risk a man will die of prostate cancer by about 21% at 11 years later," he told Medscape Medical News in an email.

Matthew Cooperberg, MD, a urologist at the University of California, San Francisco, also said that calling the test lifesaving is a stretch: "It's impossible to say for sure." But he also suspects that Stiller's prostate cancer, for which the Gleason score was 7 (3+4) and would thus be categorized as being of "favorable" intermediate risk, was serious — given that he was in his mid 40s when diagnosed and treated.

"A Gleason score 3+4 tumor at his age eventually would very likely have become clinically apparent and potentially lethal," Dr Cooperberg told Medscape Medical News.

Stacy Loeb, MD, a urologist at New York University in New York City, agreed that, even without the full details of Stiller's case, she "would consider Gleason score 3+4 prostate cancer in a 48-year-old man with a long life expectancy to be a clinically significant prostate cancer."

A Midlife Baseline Test

"Ben Stiller’s prostate cancer story is not unusual," said Otis Brawley, MD, an oncologist who is chief medical officer of the American Cancer Society (ACS), in a short essay posted on the same day and on the same website as Stiller's.

He explains that many men will have a PSA test, will eventually be diagnosed with cancer, and will believe the screening was lifesaving.

But, says Dr Brawley, the majority of men with prostate cancer, including those who go undiagnosed and untreated, will not die of their disease.

On the other hand, he says, even with careful screening, some men will die of an aggressive cancer. "This is why no major health group recommends all men be screened. The PSA test can be useful, but it is not perfect, not by a longshot," he writes.

 
This is why no major health group recommends all men be screened. Dr Otis Brawley
 

Among those major health groups is the US Preventive Services Task Force (USPSTF), which in 2012 formally recommended against routine PSA-based prostate cancer screening for healthy men, regardless of age.

As a result of this influential advisory, PSA testing has since been on the decline in the United States, even as other powerful organizations, including Dr Brawley's ACS, have advocated for some modified testing parameters.

But the USPSTF has always left room for use of the test in the clinic.

"Clinicians should understand the evidence but individualize decision-making to the specific patient or situation," reads the final USPSTF document, which was published in Annals of Internal Medicine.

This week, Dr Brawley said the same: the ACS and other organizations "suggest men of average risk be informed of the known risks and benefits of screening and make a decision about screening."

Dr Cooperberg sees the publicity from Stiller, who by his own account had an average risk of developing prostate cancer, as potentially beneficial.

"Obviously no one should get their medical advice from celebrities," said Dr Cooperberg, "but in an era when many primary care providers do not even mention PSA — or, worse, refuse to run the test when asked — anything that raises awareness and helps men start conversations with their docs should be seen as positive."

 
Obviously no one should get their medical advice from celebrities. Dr Matthew Cooperberg
 

In an email to Medscape Medical News, Dr Loeb said: "I agree completely with Ben Stiller on the value of baseline PSA measurements in the 40s. I think that men should be offered this option so that they can weigh the pros and cons to make the decision that is best for them."

She was the lead author of a study in a large group of US men that showed that the median PSA level in men in their 40s was 0.7 ng/mL, and men whose baseline PSA was above this median had a significantly higher risk of later being diagnosed with prostate cancer and with aggressive disease ( Urology. 2006;67:316-20).

Other studies from Europe have similarly found that baseline PSA levels in men in their 40s may predict which men are likely to develop life-threatening prostate cancer in the future, she added.

Furthermore, this week, Laurence Klotz, MD, a urologist at the University of Toronto in Canada, who is a pioneer in active surveillance in prostate cancer, said in a news story that Stiller is a "poster child" for the benefits of PSA screening.

In addition, Dr Klotz was paraphrased as saying that the Canadian and American expert panels that recommend against routine PSA testing are wrong and that he is in favor of an initial PSA screen for men in their mid 40s. If a PSA level is low, asymptomatic men can go untested for another 5 years, and other men can be monitored more closely.

However, Cedars-Sinai's Dr Freedland said there is no level I evidence for this strategy, referring to the lack of a randomized clinical trial.

"Many patients are screened in their 40s, and it is difficult to say it is wrong, as the best answer is really, we don't know whether starting that early makes a difference. This is no conclusive proof it is good or bad," he said.

Follow Medscape senior journalist Nick Mulcahy on Twitter: @MulcahyNick

For more from Medscape Oncology, follow us on Twitter: @MedscapeOnc

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