Analysis of the Factors, Effective on Breast Parenchymal Density in Mammogram

Breast parenchymal density is one of the factors that can cause false negative mammographic results. This work was performed to determine the frequency and distribution of dense mammograms. The peresent descriptive study was carried out from April 2003 to March 2004 on women referring to Radiology Department, Ghaem Hospital, Mashhad. A total of 1000 women with fatty (≤50% density) or dense breasts (≥ 90% density) who had screening or diagnostic mammography were studied. Breast density, breast size and presence of benign calcifications were analyzed. Clinical data such as age, parity, age at first conception, use of hormone replacement therapy (H.R.T), and family history of breast cancer were recorded and analyzed by the frequency distribution tables and descriptive statistic, Ki square and spirman test. Parenchymal density on mammograms was found to correlate with the age, and decrease progressively from 25–29 years old through 75–79 years old (Spearman correlation P = 0.001). Increased parenchymal density was more common in women who had smaller breast, and had fewer than two pregnancies, or underwent H.R.T (P < 0.001). The prevalence of benign calcifications also increased with age. This study confirmed the effectiveness of age and HRT on mammographic density, suggesting a possible reduction of mammographic sensitivity and efficacy for detecting malignancy in these groups of patients.