Table 1.

Predictors included in current contralateral breast cancer risk prediction tools

List of predictors	CBCriskb	Manchester formulac	PredictCBC version 1Ad	PredictCBC version 1Bd
Age at diagnosis	✔	✔	✔	✔
Age at first birth	✔
First-degree family history	✔	✔	✔	✔
BRCA1/2 germline mutation		✔	✔
First breast cancer behavior typea	✔	✔
Lymph node status			✔	✔
Breast density	✔
Tumor size			✔	✔
Morphology			✔	✔
Tumor grade			✔	✔
High-risk pre-neoplasia	✔
ER status	✔	✔	✔	✔
HER2 status			✔	✔
Chemotherapy			✔	✔
Endocrine therapy	✔		✔	✔
Radiation to the breast			✔	✔
Trastuzumab			✔	✔
Oophorectomy under 40 years		✔

ER estrogen-receptor status, HER2 human epidermal growth factor receptor 2

^aContralateral breast cancer risk was calculated including women diagnosed with ductal carcinoma in situ

^bChowdhury et al. [7]

^cBasu et al. [8]

^dGiardiello et al. [5]