The majority of CBCs (n = 60) were stage 0 or IA (85.0%), hormone receptor positive (94.9%), human epidermal growth factor receptor 2 (HER2/neu) negative (89.7%), and low/intermediate pathological grade (87.2%).
In conclusion, overexpression of HER2 exhibited stronger negative effect on the prognosis of ILC patients than that in IDC patients, suggesting that treatment targeting HER2 is crucial for this BC subgroup.
Regarding AGS subtypes, HER-2 and basal were more likely to recur than luminal A and B subtypes, while patients in the basal group were more likely to have CBC.
The correlation between HER-2/neu overexpression in the matched first primary and contralateral breast cancers was statistically significant, suggesting that the diagnosis of HER-2/neu overexpression in contralateral breast cancer is associated with HER-2/neu overexpression in the first primary cancer.
Further observational studies are needed to confirm these findings and to evaluate whether testing for c-erbB-2 in this population may help identify those at high risk for CBC.