Mammographic parenchymal patterns and breast cancer risk in New South Wales North Coast Aboriginal and Torres Strait Islander women

Introduction: The objective of the study was to document the distribution of mammographic parenchymal patterns (MPP) of Indigenous Australian women attending BreastScreen New South Wales (NSW) North Coast, to profile breast cancer risk as it relates to breast density and to explore the correlation between MPP, breast size as described by the posterior nipple line (PNL) and age. 

Methods: Ethics was granted from CQUniversity Human Research Ethics Committee, NSW Population Health Services Research Ethics Committee and the Aboriginal Health and Medical Research Council Ethics Committee. A quantitative retrospective analysis reviewed 502 screening mammograms against the Tabár I–V MPP classification system. The PNL was measured in millimetres (mm) and the age of the patient documented. 

Results: A statistically significant variation in the distribution of MPP (P < 0.0001) was demonstrated, with patterns of I (23.9%), II (45.6%), III (10.4%), IV (15.9%) and V (4.2%). Statistically significant differences were noted in the age of subjects between patterns (P = 0.0002). Patterns I and V demonstrated statistically significant lower ages than II, III and IV (all P < 0.05). Pattern V demonstrated a statistically significant lower age than pattern I (P = 0.0393). Pattern V demonstrated a statistically significant lower PNL value than all other patterns (all P < 0.001/P < 0.0002); pattern II was statistically significantly higher in PNL value than all other patterns (P < 0.002/P < 0.001). No significant relationship was noted between PNL and age. 

Conclusion: The study demonstrated that no identifiable or unique distribution of MPP was noted in this snapshot of Indigenous women. A larger study of Indigenous Australian women is required for validation.