The correlation between breast cancer and urinary iodine excretion levels

OBJECTIVE: To compare urinary iodine excretion levels in patients with breast cancer and control subjects. METHODS: In this prospective pilot study, patients with breast cancer and normal controls were recruited. Age and menopausal status were recorded. Levels of serum thyroid-stimulating hormone, blood urea nitrogen and creatinine and urine iodine concentration (UIC) were measured. UIC levels were divided into three categories: low (<100 µg/l), normal (100–200 µg/l) or high (>200 µg/l). RESULTS: A total of 24 patients with breast cancer and 48 controls were included in the study. There were no statistically significant differences between the two groups with regard to thyroid-stimulating hormone, blood urea nitrogen or creatinine levels. When considered overall, there was no statistical difference in UIC between patients and controls. However, comparisons within each category (low, normal or high UIC) showed a significantly higher percentage of patients with breast cancer had a high UIC compared with controls. CONCLUSIONS: A high UIC was seen in a significantly higher percentage of patients with breast cancer than controls. UIC may have a role as a marker for breast cancer screening. Further studies evaluating UIC and iodine utilization in patients with breast cancer are warranted.