According to the existing clinical data in our hospital, retrospective study was conducted to screen the risk factors with predictive value for TRC(trastuzumab-related cardiotoxicity) risk, and to construct the risk prediction model for TRC.

The breast cancer patients with cardiotoxicity caused by trastuzumab were selected as the case group, and the breast cancer patients without cardiotoxicity were selected as the control group. The clinical baseline data, echocardiographic parameters and serum markers of the case group and the control group were compared to find out the risk factors that may have predictive value for the risk of TRC. The target factors were analyzed by univariate analysis and multivariate Logistic regression analysis, and the TRC risk prediction model was established.

Inclusion Criteria:

1. Female patients diagnosed with HER2-positive breast cancer treated in our hospital.
2. Surgical treatment combined with chemotherapy or radiotherapy was completed according to NCCN guidelines, and trastuzumab standard treatment was received for at least half a year.

(3) Cardiac function (including echocardiography or biomarkers) was assessed at least once within 3 months before trastuzumab treatment, and at least once during or after treatment was performed for heart-related tests.

(4) Complete case data.

Exclusion Criteria:

1. Patients who have not been properly treated with trastuzumab or have been treated for less than half a year;
2. Patients who did not receive cardiac function assessment before trastuzumab treatment, during or after treatment;
3. Patients whose case data were missing or lost to follow-up.

All subjects were women aged >18 years, diagnosed with HER2-positive breast cancer and already receiving trastuzumab treatment.