September 25, 2018

View as List Test Your Cancer Screening Smarts

  • Test Your Cancer Screening Smarts

    Understanding the importance of cancer screening tests is key to proactively protecting your health. But screening tests aren’t magic, and it’s just as important to understand what they don’t do.

    In a study published online in May 2018 in the American Journal of Preventive Medicine, researchers asked more than 3,600 adults four true-or-false questions about cancer screenings. Surprisingly, only 5.6 percent of respondents answered all four questions correctly. 

    Curious how you stack up? Test yourself by answering true or false to the statements about cancer screenings:

  • 1

    These tests can definitely tell a person has cancer.

    man talking to doctor about diagnosis

    False. Many cancer screening tests are not diagnostic tests, meaning they cannot diagnose disease. (Pap tests are one exception.) Instead, they look for abnormal tissue or other signs that may indicate a problem.

  • 2

    When a test finds something abnormal, more tests are needed to know if it is cancer.

    biopsy under microscope

    True. Because most screenings do not directly diagnose cancer, more testing, such as a biopsy, will be done to check for cancer if an abnormal result is found.

  • 3

    When a test finds something abnormal, it is very likely to be cancer.

    doctor reassuring female patient

    False. False-positive results, which suggest cancer where there really isn’t any, are common. It’s estimated that over the span of a decade the results of 50 to 61 percent of mammograms, 10 to 12 percent of PSA tests, and about 23 percent of regular fecal occult blood tests (a stool test) will be false-positive. False-positives may be caused by another disease or no disease at all.

  • 4

    The harms of these tests sometimes outweigh the benefits.

    worried man in hospital bed

    True. Screening tests themselves carry risk. They may cause complications or side effects, or false-positive result that lead to unnecessary treatment. That's why doctors and scientists study whether the benefits of a screening test outweigh its risks before it’s recommended for widespread use. Sometimes screening makes sense for people only at high risk because of their age, health, or family history.

  • 5

    The bottom line

    medical test for cancer

    In the May 2018 study, respondents showed a poor understanding of the harms and benefits of testing, indicating that people might make screening decisions based on inaccurate information.

    This article first appeared in the August 2018 issue of UC Berkeley Health After 50.