Common cancer screening tests fail to improve survival except for colorectal cancer screening with sigmoidoscopy: JAMA

Cancer screening tests have long been hailed as essential tools in the fight against the deadly disease, with proponents asserting that they extend lifespans by detecting cancers at an early, treatable stage. However, a recent meta-analysis of randomized clinical trials has cast doubt on this assertion. The study, encompassing over 2 million individuals and spanning various commonly used cancer screening methods, found that only one test demonstrated a significant extension of lifetime.

The study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and delved into the efficacy of six prevalent cancer screening tests. These included mammography for breast cancer, colonoscopy, sigmoidoscopy, or fecal occult blood testing (FOBT) for colorectal cancer, computed tomography (CT) scans for lung cancer in smokers and former smokers, and prostate-specific antigen (PSA) testing for prostate cancer.

The results, based on a median follow-up period of 10 to 15 years across different tests, painted a nuanced picture. The only screening test that exhibited a significant gain in lifetime was sigmoidoscopy, which was associated with a noteworthy extension of 110 days (95% CI, 0-274 days). The findings for other tests were less impressive, with mammography yielding no significant change in lifetime (0 days; 95% CI, −190 to 237 days), and prostate cancer screening demonstrating an extension of 37 days (95% CI, −37 to 73 days).

Similarly, colonoscopy (37 days; 95% CI, −146 to 146 days), FOBT screening done either annually or biennially (0 days; 95% CI, −70.7 to 70.7 days), and lung cancer screening (107 days; 95% CI, −286 days to 430 days) did not show substantial gains in lifetime.

The study's implications are significant, as they challenge the notion that these commonly employed cancer screening tests significantly prolong lives. The findings suggest that, aside from colorectal cancer screening with sigmoidoscopy, the evidence doesn't adequately support the claim that these tests lead to substantial extensions of lifespans. This prompts a reevaluation of the efficacy and impact of these screening measures on overall longevity. 

Reference:

Bretthauer, M., Wieszczy, P., Løberg, M., Kaminski, M. F., Werner, T. F., Helsingen, L. M., Mori, Y., Holme, Ø., Adami, H.-O., & Kalager, M. (2023). Estimated Lifetime Gained With Cancer Screening Tests. In JAMA Internal Medicine. American Medical Association (AMA). https://doi.org/10.1001/jamainternmed.2023.3798