DYING ALONE? INVESTIGATING LONELINESS AS A RISK FACTOR FOR CANCER MORTALITY

Purpose:

Loneliness and social isolation can adversely affect the cancer patient journey with profound emotional and psychological impact. Accruing evidence suggests loneliness also has adverse effects on cancer outcomes and survival in this vulnerable population. This may be due to a variety of biological, psychological, and social factors, from impaired ability to access treatment to effects of loneliness on the immune system. We conducted the first systematic review and meta-analysis to date to investigate mortality in relation to loneliness and social isolation among cancer populations.

Materials and Methods:

We systematically searched MEDLINE, Embase, and PsycINFO from inception to September 13, 2024, for studies that report on the impact of loneliness or social isolation on all-cause and cancer mortality in cancer patients. Three reviewers independently screened titles, abstracts, and full texts using predefined eligibility criteria, with discrepancies resolved by consensus. Data extraction and risk of bias assessment was conducted using a standardized form. Random-effects meta-analysis was used to examine the association between loneliness/ social isolation with all-cause and cancer mortality.

Results:

Of 12,602 citations, 16 studies met eligibility criteria and 13 were included in the meta-analysis. Of these, 8 were prospective while 8 were retrospective, and 9 studies assessed cancer mortality while 12 examined all-cause mortality. Social isolation and loneliness were most commonly measured using the Social Network Index, Social Integration Index, and UCLA Loneliness Scale. The median sample size was 6,249, and the mean age of participants was 63 years. Meta-analysis demonstrated loneliness/social isolation may increase the risk of all-cause mortality with low certainty of evidence (hazard ratio [HR] [95% CI] = 1.34 [1.26–1.42], p<0.001). Similarly, we found loneliness/social isolation may increase the risk of cancer-specific mortality with low certainty of evidence (HR [95% CI] = 1.14 [1.04–1.25], p=0.005).

Conclusions:

Our review provides evidence that among cancer patients, loneliness and social isolation may be associated with increased risk in all-cause and cancer-specific mortality. These findings support the need to incorporate psychosocial assessments and targeted interventions into cancer care to improve patient outcomes.