Problems with screening aren’t prostate cancer-specific


According to a new report just published in the Annals of Family Medicine and summarized on Bloomberg.com, 36.7 percent of men and 26.2 percent of women who have recommended cancer screening tests for three of four different cancers will be given false positive results by the time they have undergone just four of the 14 routine tests that were possible for each patient in the study evaluated. Furthermore, about 1 in 5 men and 1 in 10 women were likely to undergo an invasive diagnostic procedure such as a biopsy as a consequence.

The data on which this report is based again come from the Prostate, Lung, Colorectal and Ovarian Cancer (PLCO) screening trial, which included a total 68,436 participants, aged 55 to 74 years, who were tested regularly for prostate, lung, colorectal, and ovarian cancers. The participants were given as many as 14 tests over the course of 3 years, in order to see whether screening tests reduce deaths from those cancers.

Many cancer screening tests are recommended to the public, as some doctors say that the earlier a malignancy is diagnosed, the easier it is to treat. However, “Messages about screening have been oversimplified to ‘Early detection saves lives,’ and that’s the end, and people are made to feel irresponsible if they don’t test,” Jennifer Croswell, the study’s lead author is quoted as saying in an interview today. She continued, “It’s a more nuanced decision than that. The more times you intervene, the greater the chance is you’re going to have harm.” Dr. Croswell is the acting director of the office of medical applications of research at the National Institutes of Health.

Over the course of the entire study period, the risk of a false positive result was 60 percent for men and 49 percent for women.

The tests used on women were vaginal ultrasounds, chest x-rays, an examination of the colon, and a chemical marker of ovarian cancer. For men, tests included the PSA test, a rectal examination (DRE), chest x-rays, and an examination of the colon.

The authors suggest that it is time to start thinking in terms of benefit-risk profiles for screening regimens rather than for individual tests. These data don’t mean that regular testing is bad. The mean that greater care needs to be taken in how we act on the results of the tests.

“This should serve as a reminder to both medical practitioners and the public that, like everything else in medicine, there’s no free ride,” Croswell is quoted as saying.

In this context, The “New” Prostate Cancer InfoLink reminds readers of two points made recently in joint statements from America’s prostate cancer organizations:

  • “Every man, regardless of his age, has the right to know whether he is at risk from prostate cancer, … We encourage all men to be proactive, and to seek out information and support in regard to their health.”
  • “We … encourage every man to discuss his individual risk for prostate cancer with his doctors, and to request the appropriate use of PSA and DRE tests until better options are available. Further clinical action based on results of these tests is also a matter for serious discussion between each patient and his physicians.”

As Dr. Peter Carroll stated in introducing the new AUA guidance on PSA screening just a couple of weeks ago, “The single most important message of this statement is that prostate cancer testing is an individual decision that patients of any age should make in conjunction with their physicians and urologists.”

One Response

  1. A related report appeared today in Modern Medicine.

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