OBJECTIVEThe aim of this study was to investigate the association between urinary cadmium and clinicopathological characteristics of breast cancer.

METHODSThe clinicopathological characteristics of 240 patients with breast cancer were obtained and urine specimens were collected from October 2009 to July 2010. The concentration of urinary cadmium was determined by inductively coupled plasma mass spectrometry (ICP-MS). χ(2) test and Wilcoxon rank sum test were used to analyze whether urinary cadmium is associated with clinicopathological characteristics of breast cancer.

RESULTSThe median concentration of urine cadmium of 240 patients was 1.99 µg/g (25th percentile, 1.32 µg/g; 75th percentile, 2.88 µg/g). HER-2 positive rate, regional/distant metastasis rate, and advanced stage rate in patients with the highest tertile of cadmium concentration were significantly higher than those in the patients with second and lowest Cd tertiles (P = 0.042, P = 0.028 and P = 0.017, respectively), and 28.2% vs. 16.5% for HER-2 and 47.2% vs. 32.0% for regional/distant metastasis, respectively. There were still significant associations between urinary cadmium levels and these clinicopathological parameters after being adjusted in age by unconditional logistic regression model, respectively (P < 0.05).

CONCLUSIONSThe results of this study suggest that urinary cadmium levels are associated with the HER-2 status, regional/distant metastasis status and stages of breast cancer, respectively. Cadmium may induce highly aggressive breast cancer in humans.