Loneliness within couples coping with cancer: prevalence, associations with physical and mental health, and potential benefits of dyadic exercise

Introduction: Cancer survivors and intimate care partners coping with cancer may each experience loneliness that impacts their health, but research within couples and potential benefit of interventions is scarce. METHODS: We added the Cancer Loneliness (CL) scale to measures of anxiety, depressive symptoms, pain and social and physical function mid-way through the Exercising Together trial (NCT03630354) in couples coping with breast (BC; n = 44) or prostate cancer (PC; n = 75). The prevalence of CL scores >1 indicated at least some loneliness and we ran correlations between CL and measures of social, physical and mental health. Within PC couples we explored the potential benefits of different types of dyadic exercise programs (supervised, group partnered exercise, supervised separate groups of survivors or partners, or unsupervised independent exercise) on CL over 6 months. Results: 96% of breast cancer survivors (BCS) and 77% of prostate cancer survivors (PCS) reported CL at baseline. CL was positively associated with anxiety (rho = 0.44, 0.77), depressive symptoms (rho = 0.60, 0.67) and pain (rho = 0.34, 0.23) and inversely associated with social functioning (rho = -0.54, -0.55) among BCS and PCS, respectively (all p < 0.01). CL was inversely associated with physical functioning in BCS (rho = -0.35), but not PCS. Among care partners, 74%-77% of care partners for each BCS and PCS reported CL related to their partner's cancer at baseline. CL was positively associated with anxiety (rho = 0.43, 0.30) and depressive symptoms (rho = 0.62, 0.45) among BC and PC care partners, respectively (all p < 0.01). CL was inversely associated with social functioning in BC partners only (rho = -0.45, p < 0.01), but not with physical functioning in either group. Within PC couples, there was a significant (inverse) interaction between change in CL over six-months of exercise and baseline loneliness. Declines in CL for both PCS and care partners were steepest in the exercise program where they trained with other PCS or care partners. Conclusion: Relationships may not offer enough social support to avoid feelings of loneliness associated with cancer that in turn affects the physical, emotional and social health of each partner. However, exercise may help rebuild connection within the couple and be an avenue for informal social support that together could reduce loneliness. Clinical Trial Registration: [clinicaltrials.gov]: identifier, [NCT03630354].