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Fewer screening tests for cancer may soon be doctor's orders
May 18th, 2011
06:00 PM ET

Fewer screening tests for cancer may soon be doctor's orders

For men being screened for prostate cancer, the results of a PSA test can become mired in confusing caveats. The test measures the level of a protein called prostate-specific antigen in a man’s blood.  A positive test may indicate the presence of a virulent form of the disease, or not, since PSA tests are not sensitive enough to distinguish between deadly cancers and those that would never kill the patient. All of that makes deciding how to interpret PSA tests difficult.

A new study may add some much-needed clarity to that process.

A large Swedish study found that men with the highest PSA levels between ages 44 and 50 were most likely to die or develop metastatic prostate cancer 30 years later. Conversely, men whose PSA levels were lower were less likely to die or develop metastatic disease.

Researchers analyzed blood samples from about 12,000 men in Sweden. The blood samples were tested for the presence of PSA at three ages -  44 to 50, 51 to 55, and at 60 - and grouped them based on highest and lowest levels.

"Forty-four percent of prostate cancer deaths occurred in men who had the top 10 percent of PSA levels when they were tested between the ages of 44 and 50," according to a study abstract that will be presented next month at the American Society of Clinical Oncology annual meeting.

"What that means is if you're 45 and you have a very low PSA, the chances you're going to develop the kind of prostate cancer that kills is very small," said Dr. Otis Brawley, chief medical officer of the American Cancer Society and CNNHealth.com expert doctor. "That's separate from saying that the chances you'll develop prostate cancer are small. The chances that you'll develop the kind that kills are small."

It is an important distinction, said Brawley.

"We have data to suggest that 60% of guys we cured of localized prostate cancer never needed to be cured and the worst thing we could have done was telling them they had prostate cancer," said Brawley.

Studies that replicate this one may eventually allow doctors to parse out which cancers will develop into serious ones, resulting in more aggressive screening for men with high PSA levels, and fewer screenings for men with lower levels.

Dr. George Sledge, president of the oncology doctors association, said this study suggests, if you have a low PSA, you may need only three PSA tests during your lifetime.

Prostate cancer screening has been muddled by controversy, in part because the test detects cancers that most likely would not have spread or killed the patient. The consequences of treating a relatively innocuous cancer are serious - infection, erectile dysfunction, bowel damage, and incontinence.

Contrary to the confusion surrounding prostate cancer screening, cervical cancer guidelines are becoming clearer. According to a large Kaiser Permanente study, most women can safely opt out of the yearly cervical cancer screening, instead getting tested every three years.

"For the time being, women should get a Pap test every three years if they've had three normal yearly Pap tests in the past, and they might want to get HPV testing, which might make things even safer," said Brawley.

Safer, perhaps, because according to the Kaiser study, testing for HPV may be a more accurate predictor than a Pap test for whether a woman will develop cervical cancer.

Researchers followed 331,818 women who had Pap tests, HPV tests, or both. After comparing the two tests, researchers found that a positive HPV test was more predictive of cervical cancer than a positive Pap. Same goes for a negative test. Women who had an HPV-negative test were less likely to develop cancer than women with a normal (or negative) Pap test.

According to the study abstract, "In routine clinical practice, a single HPV test was clearly superior to a single Pap smear for predicting who would develop... cancer within 5 years."

As a result, an HPV test could provide the best barometer for the presence of cancer, so women who get a negative HPV test might need less frequent cervical cancer screening.

Lead study author Hormuzd A. Katki of the National Cancer Institute said instead of getting both an HPV test and a Pap smear, women should be given an HPV test first. If it is negative, the Pap smear can be safely skipped.

"Pap testing should only be reserved for HPV-positive women," said Katki.

The bigger question is whether this study makes the Pap test obsolete? Not really, say study authors, but it may mean that HPV tests could soon be a bigger part of the routine at the doctor's office.


soundoff (14 Responses)
  1. Lisa

    It's good that this type of data can render the PSA a more specific test.
    Plenty of tests can detect cancer, but the question always remains- will it make a difference in survival? I know as a low risk woman I can most likely prevent colon cancer by having colonoscopies as directed, prevent cervical cancer with PAP's as directed, and have the best chance for early detection of breast cancer with mammography as directed and melanoma with skin screenings. I'm glad men's prostate cancer screening is coming along so we're closer to the goal of early intervention when it matters, and men can be left alone when it won't.

    May 18, 2011 at 19:41 | Report abuse | Reply
  2. Molly

    Yes, I too am glad they are starting to weed out unnecessary testing and worrying for patients. The CA-125 marker is another tumor marker that is not very reliable. My mother had a cancer scare a few months ago, they did a CA-125 and it was elevated. I told her it doesn't mean much since it can elevated for any number of reasons, but I know it worried her and it did me too eventhough I knew it wasn't accurate. With further tests, they determined she just had an old infection, not cancer.

    May 19, 2011 at 01:18 | Report abuse | Reply
  3. teepee

    Yep, time for the poor, old and unimformed to die and get on out of the way...

    May 19, 2011 at 06:30 | Report abuse | Reply
    • Mark

      Huh? this was not about the poor, this is about more effective testing regimens. While the poor, elderly, and sick are definitely not treated well, this was one article that makes sense.

      May 19, 2011 at 10:25 | Report abuse |
  4. less screening good!

    Radiation causes cancer, why would we want to get radiation to breasts once a year for years and years. Health costs are out the roof because of yearly screenings. Follow the money and it will eventually become apparent that we are money -making- meat -machines for docs and big medicine. And finally – you will die of something, I just don't want to die from a cancer caused by xrays and unessesary testing.

    May 19, 2011 at 07:17 | Report abuse | Reply
    • Kristin

      They didn't mention breast screenings.

      May 19, 2011 at 19:48 | Report abuse |
    • Kristin

      And don't even knock it until you go through the agony and the pain of cancer firsthand!

      May 19, 2011 at 19:49 | Report abuse |
    • Reece

      Understandable to have a fear of cancer. But you just have to be aware. I got brseat cancer 2 weeks short of my 41st birthday. My mum got it at the same time and she is still ok at 64. Anyway I suggest that you have 2 yearly smear tests. Always self check your brseats. I have never had a mammogram as I don't believe in them. They can cause cancer. So I have MRI's which are safer and more reliable. But at your age you probably just need to do self checks and maybe from about 35 have ultrasounds. But be guided by your health professional. All the best and try not to worry. Life is too short and live for each day.Kind regardsSharon

      May 27, 2012 at 00:39 | Report abuse |
  5. Kristin

    Wow. I'm speechless. I had a pap smear la few years ago, which revealed that I had cancer cells. Further tests showed that I had a Uterine squamous cell carcinoma growing in an odd spot – which was revealed through a regular YEARLY pap. If I didn't go in for my pap at that time, I would have been dead within two years. Science is amazing, and its great at what technology we have now. I was only 330!

    May 19, 2011 at 19:47 | Report abuse | Reply
    • Caytlin

      Way to judge someone else's decisions, even if their reasoning is a little out there. Glad you caught your carcinoma, but as it says in one of the linked references, cell changes in the cervix happen very slowly, so for most people, less frequent screenings make sense under the conditions described in the article. Why don't you just go ahead and get a full body MRI every year (can't be too careful) – better have skin samples taken from every part of your body too! Oh, and go out and yell at people for driving cars and crossing the street. It's a personal decision for every patient what tests and when to get them, and they don't need the anxiety created by OH NOES you didn't get your annual screen you GONNA GET CANCER!!! I choose not to get certain tests and I take full responsibility for my choices.

      May 20, 2011 at 00:41 | Report abuse |
  6. Kristin

    * Great at what technology can do now, I meant.

    May 19, 2011 at 19:47 | Report abuse | Reply
  7. Angie

    What most people don't know is you can have an HPV test ran off from your pap smear when you have it done. So if your pap smear comes back abnormal than your doctor will probably run an HPV off that sample. That way you don't have to come back to be retested. One simple call to the lab and it's done. Depending on what your pap says and what the HPV results are is how the doctor will figure out if you need to repap...have a colposcope, ect.

    May 21, 2011 at 18:14 | Report abuse | Reply
  8. repuestos rolex

    Really good post!

    June 6, 2011 at 13:45 | Report abuse | Reply
    • Tanja

      Men do get symptoms. I have a male ferind who had warts. You're speaking of the sub-clinical variety. Those don't show up like traditional warts. Sub-clinical cause cancer. I don't think the ones you can see do.

      September 14, 2012 at 00:59 | Report abuse |

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