Most cancer screenings ‘don’t extend lives’, claims review of more than 2million patients – but DON’T go canceling that test yet

Common cancer screenings aimed at detecting and treating the disease at an early stage may not be as effective in prolonging a person’s life as previously thought.

Researchers looked at clinical trials involving 2.1 million people who had six common types of tests for cancer, following them for up to 15 years and comparing the life expectancies of those who were screened and those who weren’t. had not been screened for the disease.

They found that only screening for a single cancer, colon cancer, seemed to make a difference in prolonging a person’s life, giving them just over three months longer than their peers who didn’t. had not been detected.

But experts say that doesn’t mean you should cancel that mammogram or any other screening appointments, as other data has shown screening actually reduces cancer deaths.

The study looked at deaths from all causes, not just cancer. So there could be several reasons why screening does not prolong a person’s life.

For example, some tests have harms, such as the risk of perforation of the colon during a colonoscopy or heart attack following the removal of the prostate.

There is also the risk that the tests will give a false negative and therefore a false sense of security, the researchers said.

Dr. William Dahut, scientific director of the American Cancer Society who was not involved in the study, told CNN that cancer screenings were not designed to increase a person’s lifespan, but rather to reduce premature deaths from cancer.

Dahut explained that if a person’s life expectancy at birth was estimated at 80 years, cancer screening could prevent them from dying at age 65 from cancer, but that would not necessarily mean that they would live to be 90 instead of the estimated 80. .

“Nobody says ‘if you get your cancer screenings, you’ll live to be 100.’ But we know that cancer is the second leading cause of death, the leading cause of death before age 85.

In the United States, doctors recommend certain tests for people of different ages or with certain risk factors, such as a family history of cancer or certain lifestyle habits, such as smoking.

Long considered a way to detect and diagnose cancer in its earliest stages, when it’s easier to treat, a meta-analysis of more than a dozen clinical trials has cast doubt on the effectiveness of six procedures routine screening.

In the study published on Tuesday, researchers at the University of Oslo in Sweden analyzed 18 clinical trials that followed more than 2.1 million American cancer patients for more than a decade.

The meta-analysis looked at six different screenings in cancer patients who did or did not undergo testing.

Tests observed included mammography for breast cancer, colonoscopy, sigmoidoscopy and fecal occult blood test (FOBT) for colorectal cancer, computed tomography (CT) screening for lung cancer in smokers and former smokers and a prostate specific antigen (PSA) test for the prostate. cancer.

The preventive test researchers found the longest life expectancy was a sigmoidoscopy, a colon cancer screening test that involves examining the rectum, colon and large intestine with an endoscope inserted through the anus.

Patients who underwent this test saw their life expectancy extended by 110 days.

Additionally, patients who were screened for lung cancer saw their life expectancy extended by 107 days.

However, no significant additional days of life expectancy were found in patients who underwent mammography (zero days), PSA test (37 days), colonoscopy (37 days), or FOBT (zero days).

In the United States, preventive procedures are encouraged by much of the health care community and reimbursed by many health insurance companies. However, this study, along with previous evidence, suggests that more screenings do not equate to more lives saved at the population level.

Although such testing is encouraged, little attention is paid to the possible downsides of preventive measures.

Researchers from the University of Oslo noted that cancer screenings are not benign. Although many people undergo these tests without incident, for some they could actually cause health problems.

Excessive testing can also lead to overdiagnosis. Some people who undergo cancer screening tests when cancer is detected may undergo unnecessary and potentially harmful treatment to treat slow-growing cancer that would not have harmed that person in their lifetime.

Moreover, the more tests done, the greater the risk of false positives. In addition to the mental load and anxiety, this can lead to costly and unnecessary additional tests.

But the researchers emphasize: “We are not advocating the abandonment of all screening”.

Some tests can be helpful, but “institutions and policy makers who promote cancer screening tests because of their life-saving effect may find other ways to encourage screening.”

They added that their estimates were also “uncertain” and that life expectancies varied widely.

For example, while the study found that a sigmoidoscopy would most likely extend life by 110 days, the overall period ranged from zero days to 274 days.

Although screenings may not prolong a person’s life, they can catch cancer early enough to give that person a better chance of survival and lead a healthier life throughout their initial life.