Mammographic Density Pattern in Enugu, South-East Nigeria: An audit and review of the literature

Purpose: Mammographic density portends critical radiologic and clinical implications. It is not only a limiting factor to the sensitivity of mammography in the detection of breast cancer, it has also been shown that the derse breast may upregulatethe risk of future breast cancer. It has thus generated a lot of scholarly interest. Accordingly many modifying variables of breast density have been identified and described. There is a paucity of local data on this issue. We present here a descriptive retrospective analysis of mammographic breast density pattern among patients (screening and diagnostic) seen over a four-year period, 2007-2010 at the radiodiagnosis department of the Liniversity of Nigeria Teaching Hospital (UNTH), Enugu in South-East Nigeria Method: Records of mammographic exams done at the Radiology Unit of the University of Nigeria Teaching Hospital Itiku-Ozalla, Enugu assembled, sorted and collated. Relevant parameters extracted from the records included patients' ages, mammographic breast densities and the American College of Radiology Breast Imaging Reporting and Data System(ACR BIRADS) assignment. All reports selected were accompanied by films and each mamunogram was re-assessed for mammographic dersity by a radiologist using the same mammography viewing box. The The radiologist was blinded in the accompanying radiologist's report and the mammographic breast pattern contained therein. The previous and review mammographic breast density patterns were compared and only concordant reports were accepted for the study. Bilateral mammograms which had widely varying mammographic densitieswere excluded. All mammographic densities were recorded as dense, fiber-glandular or fatty replaced. For convenience breasts in varying phases of involution were all regarded as fatty replaced. Result: The predominant breast type is the fibroglandular pattern seen in a total of 161 patients (50.5%) of the total number of patients seen. This breast pattern is seen to peak among the age group 35-49 years where 129 patients or 79% patients have fibroglandular pattern. A total of 153 patients (48%) are seen with fatty replaced breast type. In all 206 patients are below the age of 50 years. Of this, 70 patients representing 34% of the total have already transited to a fatty replaced breast type leaving 66% of patients below the age of 50years with fibroglandular or dense breast patterns. Conclusion: Majority of breast density patterns encountered in our study is the fibroglandular type. This is followed by the fatty replaced pattern. A significant proportion of women, 50 years and above still retain risk-conferring high mammographic density pattern. High mammographic density apart from its association with increased risk of breast cancer may also mask cancers already present and reduce sensitivity of mammographic detection. Complimentary imaging like ultrasonography should be optimized especially in our environment where cancers occur in comparatively younger females who are expected to have mammographically dense breasts.