Clinical and morphological factors predictive of occult involvement of the nipple-areola complex in mastectomy specimens

Abstract 

Objective

To evaluate characteristics predictive of nipple-areola complex (NAC) involvement by the breast tumor.

Study design

Cases of infiltrative ductal carcinoma (stages I, IIA and IIB) treated by mastectomy in which the distance between the tumor and the NAC was ≥2cm were included. NAC involvement was evaluated using serial histological sections. The distance between the tumor and the NAC was measured on mammograms. Other parameters taken into consideration were: tumor size, histological and nuclear grades, vascular invasion, and the presence of an in situ component. For comparisons between categorical variables, the chi-square test or Fisher's exact test were used. Student's t-test was used for numerical variables with normal distribution and the Mann–Whitney U-test was applied when distribution was not normal.

Results

Fifty patients were included. NAC was affected in 12 and unaffected in 38. There was no statistically significant difference in mean age between the unaffected and affected groups (58.9±13.5 years versus 55.8±12.5 years, p=0.477); however, 13.2% and 58.3% (p=0.046) in the NAC-unaffected and NAC-affected groups, respectively, were <50 years of age. Distance ≤3cm between the tumor and the NAC on mammograms was found in 60.5% of the NAC-unaffected group and in 100% of the NAC-affected group (p=0.007). With respect to the in situ component, there was a difference between the NAC-unaffected and NAC-affected groups regarding micropapillary pattern (13.2% versus 50.0%; p=0.014) and extensive in situ component (13.2% versus 41.7%; p=0.046). No statistically significant difference was found for any of the other parameters analyzed.

Conclusions

A distance between the tumor and the NAC ≤3cm, age <50 years, and ductal carcinoma in situ with micropapillary pattern or with an extensive in situ component were factors significantly associated with a higher likelihood of NAC involvement.

Keywords: Breast cancer, Mastectomy, Occult nipple involvement, Nipple-areola complex, Breast reconstruction