Effects of antiperspirant aluminum percent composition and mode of application on mock microcalcifications in mammography

Objective Active ingredients in antiperspirants – namely, aluminum-based complexes – can produce radiopaque particles on mammography, mimicking microcalcifications. The present study was designed to investigate whether the appearance of antiperspirant induced radiopaque particles observed on mammograms is dependent on the percentage of aluminum-based complexes in antiperspirants and/or on their mode of application. Methods A total of 43 antiperspirants with aluminum-based complex percentages ranging between 16% and 25% were tested. Each antiperspirant was applied to a single use plastic shield and then placed on an ultrasound gel pad, simulating breast tissue. Two experiments were performed, comparing antiperspirants based on (1) their percentage of aluminum-based complexes (20 antiperspirants) and (2) their mode of applications (solid, gel, and roll-on) (26 antiperspirants). Two experienced, blinded radiologists read images produced in consensus and assessed the appearance of radiopaque particles based on their density and shape. Results In experiment 1, there was no statistically significant association between the percent aluminum composition of invisible solid antiperspirants and the density or shape of the radiopaque particles (p-values > 0.05). In experiment 2, there was a statistically significant association between the shape of the radiopaque particles and the mode of application of the antiperspirant (p-value = 0.0015). Conclusions Our study suggests that the mammographic appearance of the radiopaque antiperspirant particles is not related to their percent composition of aluminum complexes. However, their mode of application appears to influence the shape of radiopaque particles, solid antiperspirants mimicking microcalcifications the most and roll-on antiperspirants the least.