Mammographic density as a risk factor for breast cancer in a low risk population.

BACKGROUND Mammographic density is a function of abundance of epithelial and connective tissue in breast. It has been identified as an independent risk factor for breast cancer in studies in western populations. We conducted a case control study to evaluate the role of mammographic density as risk factor for the development of breast cancer in Indian patients. METHODS One hundred and one cases of breast cancer and 123 healthy controls were included in the study. Mammographic density of the breast tissue of all controls and the contralateral breast of breast cancer patients was measured using a six category scale by a qualified radiologist. RESULTS A low prevalence of dense mammographic patterns (16.3% in controls and 26.7% in cases) was seen in the study population. Premenopausal women with breast density of 50% or more had 3.8 times risk of developing breast cancer than women with breast density of < 10%. (OR = 3.86, 95% CI = 1.4-10.1). In postmenopausal women with mammographically dense breast, no such increase in risk was noted. CONCLUSION High mammographic density patterns are associated with an increased risk for the development of breast cancer in younger women in a low risk population, whereas no such increase in risk is seen in postmenopausal women.