Study Shows Doctors Confused by Cancer Screening Statistics

Medical studies are supposed to help doctors make informed decisions about how to offer patients the best possible care. Increasingly, though, it appears that studies, especially those involving cancer screenings, might provide more confusion than advice.

In recent years, a controversy has evolved over when, and perhaps even whether, doctors should screen patients for cancer. Unnecessary screenings are expensive and burdensome for patients. Wait too long, though, and the patient’s life could be in danger. In addition, the doctor could be faced with a malpractice lawsuit for failure to diagnose cancer.

In large part, the confusion boils down to problems with statistics. It can be hard to measure cancer screening effectiveness in an easily understandable manner.

Take, for example, a scenario posed by researchers at the National Cancer Institute: There are three hypothetical patients, all of whom are diagnosed with cancer at age 67. They all die at age 70, making the five-year survival rate 0 percent. Three other hypothetical patients are screened and diagnosed with the same cancer at age 60. Like the patients in the first group, they also die at age 70.

In the second case, the five-year survival rate would be 100 percent, even though the patients saw no actual increase in longevity.

Most cancer screening studies draw a link between effectiveness and increases in the five-year survival rate. However, as the above example shows, this statistic may not always mean much.

Screening healthy people can result in overdiagnosis, which can artificially inflate cancer survival rates. Still, it may be the safer option for many patients. It can protect doctors too – they may find it better to screen than to risk a medical malpractice lawsuit.

In the end, researchers say that the medical community needs to do more to provide doctors with reliable evidence about cancer detection.