Pre-Diagnosis Selenium Level, Survival, and Tumor Characteristics in Women with Breast Cancer
This study utilized data from the Malmö Diet and Cancer Study, a population‐based cohort, including 17,035 women recruited from 1991 to 1996. Women with incident breast cancer (N=1066) were included (those with DCIS or bilateral breast cancer were excluded) and compared to controls without breast cancer from both matching (N=694) as well as randomization (N=492). Prediagnostic serum selenium levels were then compared, and risk of specific tumor characteristics or subtypes was determined. Breast cancer subjects were also followed for overall mortality and breast cancer-specific mortality.
While there was no association between serum selenium quartiles and tumor characteristics or subtypes, women in the highest compared to lowest selenium quartiles had lower overall mortality (HR 0.63, 95% CI: 0.44‐0.89) as well as breast cancer-specific mortality (HR 0.60, 95% CI: 0.37‐0.98).
This study adds to our knowledge about how selenium levels might affect breast cancer. Previous data (including a Cochrane systematic review) indicate that it is unlikely that serum selenium levels impact the overall risk of breast cancer, but that breast cancer mortality may be impacted by serum levels or by selenium intake. The protective effects of selenium may be limited to clinical outcomes in women with existing breast cancers, rather than to overall incidence. The benefit of baseline selenium level in this trial does not seem tied to specific subtypes or tumor characteristics.
Citation:
Sandsveden M, Nilsson E, Borgquist S, Rosendahl AH, Manjer J. Prediagnostic serum selenium levels in relation to breast cancer survival and tumor characteristics. Int J Cancer. 2020;147(9):2424-2436. doi:10.1002/ijc.33031
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