Colorectal cancer patients advocating screening to their siblings: a randomized behavioral intervention

Siblings of colorectal cancer (CRC) patients are at increased risk of developing CRC, but screening rates remain low. Through a randomized behavioral intervention, this study aimed to determine whether patients can advocate screening to their siblings using a tailored educational package.

CRC survivors were recruited and randomized into relaying either tailored materials (intervention group) or existing national screening guidelines (control group) to their siblings. Siblings could respond to the study team if they were interested in learning about CRC screening. Study outcomes were patient advocacy rates (number of patients who had successfully contacted at least 1 eligible sibling) between groups and the proportion of eligible siblings who responded.

Between May 2017 and March 2021, 219 CRC patients were randomized to the intervention (n = 110) and control (n = 109) groups. Patient advocacy rates were high and did not differ significantly between groups. However, only 14.3% of eligible siblings (n = 85) responded to the study team. Siblings of patients from the intervention group were more likely to respond (adjusted odds ratio, 1.8; 95% confidence interval, 1.1-3.0; P < .05). Moreover, after controlling for potential confounders, siblings aged ≥60 years were significantly less likely to respond (adjusted odds ratio, .3; 95% confidence interval, .1-.7; P < .01).

CRC patients are willing advocates of screening, and siblings contacted by patients from the intervention group were also more likely to reach out to the study team. However, overall sibling response rates were low despite advocacy, suggesting that patient-led advocacy should at best be used as an adjunct to other, multipronged CRC screening promotion modalities.