Overview

• Published October 14, 2025 in BMJ Oncology, the study systematically reviewed 16 studies and pooled data from 13 of them.
• Across roughly 1.64 million patients with cancer, loneliness was associated with a 34% higher all-cause mortality and an 11% higher cancer-specific mortality after adjusting for small-study effects.
• The evidence base spans cohorts from Canada, England, Finland, France, Ireland, Japan and the United States across multiple cancer types.
• Exposure to loneliness and social isolation was primarily assessed using validated tools such as the Social Network Index and the UCLA Loneliness Scale.
• Authors note heterogeneity and limited control for confounders as major constraints and outline stress-related immune dysregulation plus psychological and behavioral pathways as plausible mechanisms.