Urinary 8-Hydroxy-2′-Deoxyguanosine, Oxidative DNA Damage and Health-Related Quality of Life in Albanian Patients with Cancer: A Case–Control Study

Background/Objectives: Oxidative DNA damage contributes to cancer development and progression, but its relationship with health-related quality of life (HRQoL) remains insufficiently explored. This study evaluated urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels and their relationship with HRQoL in Albanian patients with cancer. Methods: This case–control study included 106 patients with histologically confirmed cancer and 35 healthy controls. Urinary 8-OHdG was measured by enzyme-linked immunosorbent assay (ELISA) and normalized to urinary creatinine. HRQoL was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). Associations between urinary 8-OHdG levels and HRQoL domains were evaluated using correlation analyses and multivariable linear regression. Results: Urinary 8-OHdG levels were significantly higher in patients than controls (median 21.04 vs. 5.65 ng/mg creatinine; p < 0.001). Levels differed significantly according to time since diagnosis, with the highest levels observed within the first year after diagnosis (p < 0.001). Higher 8-OHdG concentrations were associated with poorer global health status, reduced physical, emotional, cognitive, and social functioning, and increased symptom burden. In multivariable analysis, urinary 8-OHdG remained independently associated with lower physical functioning after adjustment for age, sex, smoking status, and time since diagnosis (β = −1.032, p < 0.001). Conclusions: Among Albanian patients with cancer, increased oxidative DNA damage was associated with impaired functional status and poorer HRQoL. Urinary 8-OHdG may represent a useful non-invasive biomarker reflecting disease-related burden and patient well-being. Longitudinal studies are needed to clarify the role of oxidative stress in cancer progression, treatment effects, and quality-of-life outcomes.