New tests will refine prostate cancer diagnoses

03/27/2013 12:00 AM

03/26/2013 11:46 PM

Sophisticated new prostate cancer tests are coming to market that might supplement the unreliable PSA test, potentially saving tens of thousands of men each year from unnecessary biopsies, operations and radiation treatments.

Some of the tests are aimed at reducing the false alarms, and accompanying anxiety, caused by elevated PSA readings. Others, intended for use after a definitive diagnosis, probe the genetic workings of the cancer to distinguish dangerous tumors that need treatment from slow-growing ones that might be left alone.

The tests could provide a way out of the bitter debate over whether healthy men should be screened for prostate cancer.

The problem with the PSA blood test is that many of the cancers it detects are unlikely to cause harm.

But there is no reliable way to identify them.

So a large majority of men with positive tests undergo surgery or radiation treatment, and many suffer for years, needlessly, from such complications as incontinence and erectile dysfunction.

In late 2011, the U.S. Preventive Services Task Force, a government advisory body, provoked a furor by recommending against screening, saying that far more men were harmed by unnecessary biopsies and treatments than were saved from dying of cancer.

But if new tests can better determine risk, screening could become more useful.

"It's not that screening doesn't work; it's that we haven't done a great job of targeting treatments for the tumors that need it," said Dr. Matthew Cooperberg, an assistant professor of urology at the University of California, San Francisco, who has been a consultant to some of the testing companies.

Reducing unnecessary treatments could also reduce the $12 billion in estimated annual spending related to prostate cancer. Test developers hope that such savings will make their tests cost-effective, even at prices that will exceed $3,000 in some cases.

More than a dozen companies have introduced tests recently or are planning to do so.

Rather than looking at a single protein such as PSA, which stands for prostate-specific antigen, many of these tests use advanced techniques to measure multiple genes or other so-called molecular markers.

"It's the cancer for the next 18 to 24 months that will be transformed by molecular markers," said Dr. Doug Dolginow, CEO of GenomeDx Biosciences, a startup planning to introduce a test later this year.

Experts caution that it is too early to tell how well most of the tests will perform and whether they will make a difference.

Although the tests are intended to help men make treatment decisions, the onslaught of so many could cause more confusion.

"It's a little tricky to find out which one applies to you and whether it will be paid for by insurance," said Jan Manarite, who runs the telephone help line for the Prostate Cancer Research Institute, a patient education organization.

Prostate cancer specialists say that screening has declined since the task force recommended against it, but millions of men in the United States still get regular blood tests to measure PSA. As many as 1 million undergo biopsies each year, with about 240,000 prostate cancer cases diagnosed and 28,000 deaths from the disease.

The biggest battle among test developers could be between Genomic Health and Myriad Genetics, which are moving into the prostate cancer field after successes in breast cancer testing.

Myriad is known for its test for genetic mutations that raise a woman's risk of getting breast cancer.

Genomic Health's Oncotype DX test helps determine if a woman should receive chemotherapy.

Both companies have developed prostate tests analogous to Oncotype DX. They analyze gene activity levels in the tumor sample obtained by biopsy to gauge how aggressive the cancer is, helping doctors and patients decide whether to treat it.

The companies say their tests provide better information than the Gleason score, the main tool now used to assess tumor aggressiveness, which is based on how cells look under a microscope.

"We already know from conventional information that there are a group of men who are very unlikely to have progression, but they still get treated," said Dr. Lee Newcomer, senior vice president for oncology at UnitedHealthcare.

Angel Vasquez, for example, resisted when his urologist told him that he could forgo treatment based on his low Gleason score and PSA levels.

"I said, 'No, my philosophy is if there is something in my body that is not supposed to be there, I want it to come out,' " said Vasquez, 67, of Matthews, N.C.

The doctor ordered Myriad's Prolaris test. Rather than justifying a decision to watch and wait, the test showed the tumor to be more aggressive than thought, a finding later confirmed after Vasquez had surgery.

"Had I left it alone, it would have really progressed," he said.

Some experts say that even if the new tests are not perfect, they are better than what is available now.

"Even if we can only convince 15 to 20 percent of men that we have enough confidence that they don't need to be treated, that will be a big step forward," said Dr. Eric Klein of the Cleveland Clinic, who has worked with Genomic Health.

Some experts say unnecessary procedures can be reduced simply by using the PSA test less frequently, and also by improving imaging.

The new tests are "singles and doubles at best," said Dr. William Catalona, director of the prostate program at Northwestern University, who helped bring the PSA test to market in the 1990s.

But, Catalona said, this is only the start.

"This field is moving kind of like cellphones," he said.

The tests could provide a way out of the bitter debate over whether healthy men should be screened for prostate cancer. Many cancers detected by PSA blood tests are unlikely to cause harm, but there is no reliable way to identify them.

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