From a JAMA Network Open online release (Jan 31, 2020):
Steep incidence increases between 49 and 50 years of age are consistent with previously undetected colorectal cancers diagnosed via screening uptake at 50 years. These cancers are not reflected in observed rates of colorectal cancer in the SEER registries among individuals younger than 50 years. Hence, using observed incidence rates from 45 to 49 years of age alone to assess potential outcomes of earlier screening may underestimate cancer prevention benefits.
Early-onset colorectal cancer (EOCRC) incidence rates are increasing, and controversy exists regarding whether average-risk screening should begin at 45 or 50 years of age.1 In 2018, the American Cancer Society recommended that average-risk screening start at 45 years of age.2 Others recommend screening at 50 years of age, although the US Multi-Society Task Force on Colorectal Cancer recommends screening African American individuals at age 45 years of age owing to higher incidence, mortality, and earlier-onset disease.3–6 The American Cancer Society decision incorporated modeling studies that used updated incidence and mortality data encompassing time periods of increasing EOCRC incidence rates; modeling compared life-years gained by initiating screening at 45 vs 50 years.
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