Cross-lagged longitudinal analysis of pain and fear of cancer recurrence in young female survivors of breast and gynaecological cancers.

Chronic cancer-related pain affects up to 40% of cancer survivors, yet why pain persists after cancer treatment has ended is not well-understood. The Cancer Threat Interpretation (CTI) model proposes that fear of cancer recurrence (FCR) may perpetuate pain, yet research testing the CTI model to date has been largely cross-sectional. This longitudinal study assessed pain and FCR in 111 Adolescent and Young Adult (18-39 years) survivors of breast and gynaecological cancers, a group at high risk for FCR and long-term impact of pain. Pain and FCR were measured every 2 months over 3 timepoints. We estimated cross-lagged panel models using a multilevel mixed-effects framework, including random intercepts for each construct to account for stable between-person differences. Results showed that FCR predicted future pain within individuals (β = 0.167, P = 0.011), while pain did not predict future FCR (β = 0.038, P = 0.489). Similar findings emerged for fatigue, suggesting FCR may influence postcancer symptom burden beyond pain. This study provides more robust evidence for the CTI model and highlights the potential of targeting FCR to reduce the burden of chronic cancer-related pain.