Study on Mammographic Breast Pattern in Postmenopausal Women in Ibadan, South-Western Nigeria

Introduction: Mammographic density is a strong predictor of breast cancer. Menopause has a significant effect on breast pattern and has been documented to have more important influence on the decline in mammographic densities than age. The aim of this study was to describe the breast parenchymal density patterns in postmenopausal women in Ibadan and correlate these with their socio-demographic and anthropometric characteristics.

Methodology: This is a retrospective cross-sectional study of 196 postmenopausal women who had two screening views done on each breast in the Radiology Department of the University College Hospital Ibadan. Data was pulled from completed questionnaire by patient who had mammogram during the period under review. The report of the mammograms were matched with patients’ socio-demographic characteristics and entered into R statistical package for analysis.

Results: The mean age of the women was 55.0±6.8 years while their mean age at menopause was 48.4±4.6 years. The combined BI-RADS 1 and 2 breast parenchymal patterns which are associated with low risk of breast cancer, were found in 82.1% of the women. The mean difference in age at first birth between women with BI-RADS 1 and 2 and BI-RADS 3 and 4 was statistically significant P=0.035. Body mass index, family and personal history of breast cancer also showed correlation with breast parenchymal pattern, though not statistically significant.

Conclusion: The low prevalence of dense breast pattern in this study is consistent with previous findings of relatively lower prevalence of breast cancer in African women. The clustering of low mean age at birth of first child, low mean age at menopause and multi-parity, in association with the low mammographic density in majority of the women in this study further corroborates the relatively reduced risk of breast cancer in our studied population.