INTRODUCTION: In 2018, colorectal cancer (CRC) was the fourth most incident cancer worldwide (10.2%) and the third leading cause of cancer death (9.2%). Its early diagnosis allows the institution of treatment in earlier stages of cancer, promoting a reduction in its morbidity and mortality. This study aims to evaluate the effectiveness of population screening for CCR by fecal occult blood tests in adults aged from 45 to 75 years. METHODS: The outcomes were overall mortality and CRC mortality. Search strategies were applied to MEDLINE, EMBASE, LILACS and CENTRAL. Five reviewers independently selected the studies. For each selected clinical trial, the risk of bias was assessed according to the criteria described in the Cochrane Manual for Systematic Reviews of Interventions. Reviewers used a specific data extraction form to record information from the selected studies. The relative risk (RR) was calculated with a 95% confidence interval (CI) as an estimate of the intervention’s effect. Similar outcomes were plotted in the meta-analysis and a random-effect model was used for the meta-analysis. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to evaluate the certainty of evidence. RESULTS: Twelve randomized controlled trials (RCTs) were included, in which asymptomatic individuals – with standard risk for CRC – underwent guaiac fecal occult blood test (gFOBT), while the control group was not screened. In total, 337.377 individuals were screened with gFOBT and biennial frequency (intervention group), while 337.192 individuals did not participate in the screening (control group). In relation to mortality due to CRC, a reduction of 12% was verified (RR: 0.88, 95% CI, 0.84 to 0.92, twelve studies, 674.569 participants, moderate quality of evidence) in the intervention group compared to the control group. We found no significant difference in the overall mortality (RR 1.00, 95% CI, 1.00 to 1.01, moderate quality of evidence). CONCLUSION: Population screening for CRC in individuals aged from 45 to 75 years was able to reduce mortality from this cancer by 12% and had no effect on overall mortality.
Funding: São Paulo State Research Support Foundation (FAPESP). Process number: 2019/19386-2
PROSPERO (registration number: CRD42020169541)