CancerPreventive Medicine


Here’s a disappointing statistic! Screening for cancers was shown not to extend one’s lifespan.

In other words, cancer screenings are recommended for everyone, but in only a few situations do they prolong your life.

Over 2.1 million individuals were studied retrospectively to assess whether six common cancer screenings resulted in a longer life span. The 6 screenings were prostate specific antigen (PSA), fecal occult blood testing, sigmoidoscopy, colonoscopy, mammography, and chest CT.

The observation periods for evaluation were 10 years for PSA and chest CT, 13 years for mammography, and 15 years for fecal occult blood testing, sigmoidoscopy, and colonoscopy. The life span of patients screened was compared to that of patients who were not screened. 

The results were not as was hoped:

Prostate Specific Antigen (PSA) Testing for prostate cancer added 37 days on average. The range in days was -37 to +73 with an average of 37 days.

Mammography Imaging for breast cancer added zero (0) days on average. The range in days was -190 to +237 with an average of zero. 

Colonoscopy studies for colorectal cancer added 37 days on average. The range was -146 to +146 with an average of 37 days.

Fecal Occult Blood Testing (FOBT) for colorectal cancer added zero (0) days on average. The range was -70.7 to +70.7 with an average of zero (0) days.

Chest Computed Tomography (CT) for lung cancer added 107 days on average. The range was -286 to +430 days with an average of 107 days.

Sigmoidoscopy screening for colorectal cancer added 110 days on average. The range was 0 to +274 days with an average of 110 days. 

The results of this study question the claims by the American Cancer Society, urologists, gastroenterologists, and pulmonologists that common cancer screenings save lives and extend the length of peoples’ lives. It appears that only sigmoidoscopy increases the length of life to a statistically significant degree. That is surprising because colonoscopy is the recommended gold standard for colorectal cancer screening, and sigmoidoscopies are done much less often. While chest CT adds 107 days to one’s life, the number of people in the -286 days whose lives are shortened is weighted statically enough to lessen the significance of the positive days. Chest CT misses enough lung cancers to class it as ineffective at lengthening life span. 

The purpose of cancer screenings is to detect cancer early. Early detection is touted as one of the most effective ways to beat cancer. This study does not substantiate that claim. BUT I think it will not alter the current recommendations. To merely say statistics do not support the value of cancer screenings and take a nihilistic approach would be a defeatist attitude. That attitude would cause an upward surge in cancer deaths. 

In my opinion, anything that is done proactively for early cancer detection is beneficial and should continue to be recommended. Whether it has the ultimate benefit of prolonging one’s life is important, but enigmatically the results confound logic. These results underscore the unpredictability of cancer treatment. One can be diagnosed early, but if the cancer is aggressive and incompletely removed, length of life is affected. More study is needed to improve early detection at the genetic or microscopic level. An analysis of a person’s DNA to detect the tendency to develop cancer would be a huge benefit.

Reference: Bretthauer M, Wieszczy P, Loberg M Estimated Lifetime Gained With Cancer Screening Tests—A Meta-analysis of Randomized Clinical Trials JAMA Intern Med 2023 August 28. doi:10.1001/jamainternmed.2023.3798

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