10-Year Lag in Survival Benefit After Cancer Screening
(HealthDay News) – Breast and colorectal cancer screening have, on average, a 10-year time lag to survival benefit, according to a meta-analysis published online Jan. 8 in BMJ.
Sei J. Lee, MD, from the University of California in San Francisco, and colleagues conducted a meta-analysis using survival data from population-based, randomized, controlled trials comparing populations (≥40 years old) screened and not screened for breast or colorectal cancer (using mammography and fecal occult blood testing, respectively).
The researchers used five breast and four colorectal cancer screening trials to examine the estimated length of time needed after screening to observe a survival benefit. It took 3 years before one death from breast cancer was prevented for every 5,000 women screened and, on average, 10.7 years before one death from breast cancer was prevented for 1,000 women screened. It took 4.8 years before one death from colorectal cancer was prevented for 5,000 patients screened and, on average, 10.3 years before one death from colorectal cancer was prevented for 1,000 patients screened.
"Our results suggest that screening for breast and colorectal cancer is most appropriate for patients with a life expectancy >10 years," the authors write.