Mammographic parenchymal pattern and breast cancer risk profile of Papua New Guinean women - A baseline study of the screening population

Introduction: The aim of this research is to evidence for the first time the breast density of Papua New Guinean (PNG) women as described by mammographic parenchymal patterns (MPPs) and profile breast cancer risk; to examine the relationship of age and MPPs. Methods: A retrospective analysis of 1161 screening mammograms of women who had undergone imaging at the Pacific International Hospital (PIH) was undertaken. Mammograms were classified into one of five Tabár MPPs; age was recorded in years. Descriptive analysis of the data for pattern distribution and a chi-square test, to test for relationships between age and pattern type were undertaken. Results: The majority (51.42%) of women had Pattern I breasts; Pattern II (30.58%), Pattern III (4.31%), Pattern IV (7.24%), and Pattern V (6.46%). The mean age was 38.8 with a range of 30-80 years; there were no obvious differences in mean age across the categories of patterns. A chi-square test reported no evidence of a relationship between age and pattern type (p-value = 0.504). Pattern V differed from other patterns, with proportionally more women aged over 50 and less aged in their 40s. Conclusion: This study sets a baseline for future studies of the MPPs of PNG women, and demonstrated that in this snapshot of PNG women, there is no unique distribution of MPPs and no increased risk of breast cancer based on breast density profile. This result does not help to explain the high incidence of breast cancer in PNG. A more comprehensive study of the PNG screening population is required to validate this study.