Recommended cancer screening may not extend patients’ life spans, according to research published in JAMA Internal Medicine.1
Researchers conducted a meta-analysis of trials designed to evaluate the effects of screening for breast, colorectal, prostate, and lung cancers.
The results suggested that only screening for colorectal cancer using sigmoidoscopy can extend patients’ life spans.
The meta-analysis included randomized trials that reported data on all-cause mortality and estimated lifetime gained associated with 6 tests used for cancer screening:
- Mammography for breast cancer
- Colonoscopy, sigmoidoscopy, and fecal occult blood testing (FOBT) for colorectal cancer
- CT for lung cancer in current and former smokers
- Prostate-specific antigen (PSA) testing for prostate cancer.
The 18 included trials encompassed more than 2.1 million individuals. The median follow-up was 10 years for CT, PSA testing, and colonoscopy; 13 years for mammography; and 15 years for sigmoidoscopy and FOBT.
For most of the screening methods, there was no significant difference in lifetime gain between the screening and no-screening groups.
Only sigmoidoscopy was associated with a significant lifetime gain, which was 110 days. The lifetime gain was 0 days for mammography, 0 days for yearly or biyearly FOBT, 37 days for PSA testing, 37 days for colonoscopy, and 107 days for lung cancer screening.
The absolute risk of all-cause death per 100 person-years was:
- 0.65 both in patients who underwent mammography and in those who did not (relative risk [RR], 1.00; 95% CI, 0.95-1.04)
- 1.8 in patients who had FOBT every year and in those who did not (RR, 1.00; 95% CI, 0.98-1.03)
- 1.8 in patients who had FOBT every other year and in those who did not (RR, 1.00; 95% CI, 0.99-1.01)
- 0.95 in patients who underwent sigmoidoscopy and 0.97 in those who did not (RR, 0.98; 95% CI, 0.95-1.00)
- 1.1 in patients who underwent colonoscopy and in those who did not (RR, 0.99; 95% CI, 0.96-1.04)
- 1.3 in patients who had PSA testing and in those who did not (RR, 0.99; 95% CI, 0.98-1.01)
- 1.2 in patients who underwent lung cancer screening and in those who did not (RR, 0.97; 95% CI, 0.88-1.08).
“Although our meta-analysis suggests that claims that screening saves lives are not substantiated by the current best available evidence, we do not advocate that all screening should be abandoned,” the researchers wrote. “Screening tests with a positive benefit-harm balance measured in incidence and mortality of the target cancer compared with harms and burden may well be worthwhile.”
“To avoid harm and increase benefits, we believe that health care representatives and experts must be honest, transparent, and dispassionate about the benefits and harms of screening, expressed in a way that allows real shared decision-making,” three of the researchers wrote in a related viewpoint article.2
Authors of a related special communications article argued that “screening leads to many more people being negatively affected” by more testing, procedures, false alarms, overdiagnosis, and financial toxicity.3
“Thus, the critical question is whether the benefits for the few are sufficiently large to warrant the associated harms for many,” the authors added.
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original references for a full list of disclosures.
1. Bretthauer M, Wieszczy P, Loberg M, et al. Estimated lifetime gained with cancer screening tests: A meta-analysis of randomized clinical trials. JAMA Intern Med. Published online August 28, 2023. doi:10.1001/jamainternmed.2023.3798
2. Adami H-O, Kalager M, Bretthauer M. The future of cancer screening—Guided without conflicts of interest. JAMA Intern Med. Published online August 28, 2023. doi:10.1001/jamainternmed.2023.4064
3. Welch HG, Dey T. Testing whether cancer screening saves lives: Implications for randomized clinical trials of multicancer screening. JAMA Intern Med. Published online August 28, 2023. doi:10.1001/jamainternmed.2023.3781