Biomonitoring of organochlorines in women with benign and malignant breast disease

Established risk factors for breast cancer explain breast cancer risk only partially. Organochlorines are considered to be a possible cause for hormone-dependent cancers. A hospital-based case-control study, the first from India, was conducted among 50 women undergoing surgery for breast disease to examine the association between organochlorine exposure and breast cancer risk. Blood, tumor, and surrounding adipose tissue of the breast were collected from the subjects with benign (control) and malignant breast (study) lesions and analyzed to determine organochlorine insecticides using a gas-liquid chromatograph equipped with an electron capture detector. The alpha, beta, gamma, and delta isomers of hexachlorocyclohexane (HCH), p,p'-dichlorodiphenyltrichloroethane (DDT), o,p'-DDT, p,p-dichlorodiphenyldichloroethylene, and p,p'-dichlorodiphenyldichloroethane were frequently detected in three specimens. Total HCH and total DDT levels were higher in the blood of the study group (25 cases) than in those of the controls (25 cases) with only gamma-HCH being significantly different (P<0.05). However, both total HCH and total DDT were higher in the tumor tissues of the controls than in those of the study group; gamma-HCH was significantly different (P<0.05). The level of total HCH (alpha-HCH was significantly different, P<0.05) was higher in the breast adipose tissue of the study group, whereas total DDT was higher in the breast adipose tissue of the control group. The distribution of known confounders of breast cancer including age, body mass index, age at menarche and menopause, duration of breast feeding, and family history related to breast disease did not differ significantly between benign and malignant groups. This pilot study with limited statistical power does not support a positive association between exposure to organochlorines and risk of breast cancer but paves the way for a larger Indian study with greater statistical power encompassing different regions of the country to enable statistically sound conclusions.