Mailed Outreach Is Superior to Usual Care Alone for Colorectal Cancer Screening in the USA: A Systematic Review and Meta-analysis

Mailed outreach promoting colorectal cancer (CRC) screening with a stool blood test kit may increase participation, but magnitude and consistency of benefit of this intervention strategy is uncertain. Our aim was to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing mailed outreach offering stool tests to usual care, clinic-based screening offers on CRC screening uptake in the USA. We performed a systematic literature search of five databases for RCTs of mailed outreach from January 1980 through June 2017. Primary outcome was screening completion, summarized using random-effects meta-analysis as pooled differences in proportion completing the screening and relative risk of achieving screening compared to control. Subgroup analyses by test type offered—fecal immunochemical test (FIT) or guaiac fecal occult blood test (gFOBT), the presence of telephone reminders, and the presence of predominant underserved/minority population within study were performed. Quality of evidence was evaluated using the GRADE framework. Seven RCTs which enrolled 12,501 subjects were included (n = 5703 assigned mailed outreach and n = 6798 usual care). Mailed outreach resulted in a 28% absolute (95% CI 25–30%; I² = 47%) and a 2.8-fold relative (RR 2.65, 95% CI 2.03–3.45; I² = 92%) increase in screening completion compared to usual care, with a number needed to invite estimated to be 3.6. Similar outcomes were observed across subgroups. Overall body of evidence was at moderate quality. Mailed outreach offering a gFOBT or FIT is associated with a large and consistent increase in CRC screening completion and should be considered for more widespread implementation for improving screening rates nationwide.