While the results of the Bretthauer et al trial are important, randomized trials that directly compare the effectiveness of different colorectal cancer screening strategies are lacking. The Forsberg et al trial, also an ongoing study, seeks to address this vitally important gap in our current data. The SCREESCO trial is a study that compares the efficacy of colonoscopy with FIT every 2 years or no screening. The currently reported data are preliminary but show a similarly low rate of colonoscopy screening in those invited to do so (35%). This is a similar limitation to that noted in the Bretthauer et al study. Furthermore, there is some question regarding colonoscopy quality in this study, which had a very low reported adenoma detection rate.
While the current studies are important and provide quality randomized data on the effect of colorectal cancer screening, there remain many unanswered questions. Should the results presented by Bretthauer et al represent the current real-world scenario, then colonoscopy screening may not be viewed as an effective screening tool compared to simpler, less-invasive modalities (ie, FIT). Further follow-up from the SCREESCO trial will help shed light on this question. However, there are concerns with this study, including a very low participation rate, which could greatly underestimate the effectiveness of screening. Additional analysis and longer follow-up will be vital to fully understand the benefits of screening colonoscopy. In the meantime, screening remains an important tool for early detection of colorectal cancer and remains a category A recommendation by the United States Preventive Services Task Force.4
Applications for Clinical Practice and System Implementation
Current guidelines continue to strongly recommend screening for colorectal cancer for persons between 45 and 75 years of age (category B recommendation for those aged 45 to 49 years per the United States Preventive Services Task Force). Stool-based tests and direct visualization tests are both endorsed as screening options. Further follow-up from the presented studies is needed to help shed light on the magnitude of benefit of these modalities.
Practice Points
- Current guidelines continue to strongly recommend screening for colon cancer in those aged 45 to 75 years.
- The optimal modality for screening and the impact of screening on cancer-related mortality requires longer- term follow-up from these ongoing studies.
–Daniel Isaac, DO, MS