Introduction
A cancer diagnosis can severely impact mental health, but knowledge about high-risk groups is lacking. The aim of this study was to estimate the cumulative incidence of depression among cancer survivors and to examine associations with sex, age, prognosis, and time since diagnosis across the 25 most common cancers.
Method
This nationwide register-based study included adults diagnosed with a primary cancer between 1997–2022 and a matched cancer-free cohort (1:5). Depression was defined based on redeemed prescriptions or hospital diagnoses. Analyses were performed both overall and for the 25 most common cancer types. We calculated 1- and 10-year cumulative incidence and estimated incidence rate ratios (IRRs) in relation to sex, age, prognosis, and time since diagnosis.
Results
Among 532,747 cancer survivors and 2,663,735 cancer-free individuals, the 10-year cumulative incidence of depression was higher among cancer survivors (20%, CI 19.8–20.6) than among the cancer-free population (16%, CI 15.9–16.0). Among men, IRRs ranged between 2.51 (CI 1.43–4.40) for testicular cancer to 17.0 (CI 15.2–19.0) for pancreatic cancer in the first year after cancer diagnosis. In addition, depression incidence was slightly elevated in women (IRR 1.07, CI 1.04–1.10) and highest among those aged ≥80 vs. 60–69 years (IRR 1.23, CI 1.19–1.27). Risk was lower in patients with poor prognosis (excess mortality ≥40%) compared to better prognosis (<20%) (IRR 0.28, CI 0.28–0.29). More than ten years after the cancer diagnosis, the incidence remained elevated, but sex- and age-specific differences resembled those seen in the cancer-free cohort.
Conclusion
One in five cancer survivors experience depression within 10 years. The incidence was highest in those with a poor prognosis and was less dependent on sex and age than in the general population. The risk of depression remained elevated more than 10 years after diagnosis, highlighting the importance of long-term, comprehensive attention to depression among cancer survivors.