Family and social functioning deficits in patients with colorectal cancer accompanied by stoma formation: a cross-sectional study examining the mediating role of social support

Background Patients with colorectal cancer and ostomy frequently experience deficits in social functioning, which may adversely affect their quality of life. Although family functioning and social support are recognized as factors associated with lower social functioning deficits, the mechanisms connecting these variables remain unclear. The present study examined whether social support mediates the association between family functioning and social functioning deficits. Methods A cross-sectional survey was performed among 297 patients with CRC and an ostomy, selected by convenience sampling between September 2025 and July 2026. Data were obtained using the Social Dysfunction Screening Scale, the Family APGAR Index, and the Social Support Rating Scale. Spearman correlation, multiple linear regression, and bootstrap mediation analyses were conducted. Results Both family functioning and social support showed significant associations with social functioning deficits and together explained 91.0% of the variance. Family functioning was positively related to social support (β = 0.836, P < 0.001), which in turn was inversely associated with social functioning deficits (β = -0.421, P < 0.001). The indirect effect through social support was significant (standardized β = -0.352, 95% CI: -0.422 to -0.284) and accounted for 40.0% of the total effect. However, substantial measurement overlap among the three scales warrants cautious interpretation of this statistical indirect association. Conclusions Social support was associated with the relationship between family functioning and social functioning deficits. Family functioning was both directly and indirectly associated with social functioning through social support; however, substantial measurement overlap warrants cautious interpretation. These findings suggest that family functioning and social support are closely intertwined with social functioning in patients with colorectal cancer and a stoma, but longitudinal or intervention studies are needed to confirm any causal or interventional benefits.