To analyze the efficacy of pyrotinib in the patients with HER-2-positive breast cancer and identify risk factors associated with poor prognosis.

A retrospective cohort study was conducted, involving 250 HER-2-positive breast cancer patients in the People’s Hospital of Yuechi County, Sichuan Province from May 2020 to May 2023. Among them, 125 patients receiving pyrotinib combined with conventional chemotherapy served as the observation group, and 125 patients undergoing conventional chemotherapy served as the control group. The chemotherapy efficacy and adverse reaction rates between the two groups were compared using χ² test. Progression-free survival (PFS) was analyzed using the Kaplan-Meier method, with log-rank tests used for intergroup PFS comparisons. Cox proportional hazards models were used for multivariate analysis of potential risk factors of poor prognosis. Patients were randomly divided into a modeling group and a validation group (7∶3 ratio) using simple random sampling. The R 4.1.0 software with the rms package was utilized to establish a prognostic prediction model for HER-2-positive breast cancer. Bootstrap validation was performed to calculate the concordance index (C-index) . Receiver operating characteristic (ROC) curves were plotted, and the area under the curve (AUC) was computed to evaluate the predictive value of the nomogram model.

The overall response rate was significantly higher in the observation group than in the control group (86.4% vs 69.6%, χ²=10.280, P=0.001) . No significant difference was found in the incidence of adverse reactions between two groups (all P>0.050). After a median follow-up of 24 months, the PFS was significantly longer in the observation group than in the control group [20.0 (18.0, 21.0) months vs 17.0 (16.0, 19.0) months, Z=16.673, P<0.001]. Among the 175 patients in the modeling group, 39 (22.3%) had poor prognosis, while 16 out of 75 patients (21.3%) in the validation group experienced poor prognosis, with no significant intergroup difference (χ²=0.028, P=0.868) . Multivariate analyses identified visceral metastasis (HR=2.684, 95%CI: 1.056-6.821, P=0.038) , Ki-67 positivity (HR=8.209, 95%CI: 3.048-22.106, P<0.001) , clinical stage Ⅲ (HR=4.038, 95%CI: 1.865-8.744, P<0.001) , and elevated expression of TNF-α (HR=7.433, 95%CI: 3.370-16.396, P<0.001) , IL-6 (HR=1.066, 95%CI: 1.004-1.131, P=0.036) and IL-8 (HR=1.735, 95%CI: 1.251-2.406, P=0.001) as independent risk factors for poor prognosis. The C-index values were 0.938 and 0.946 in the modeling and validation group, respectively, with calibration curves closely aligned to the ideal curve. The modeling group achieved an AUC of 0.936 (95%CI: 0.879-0.993, P<0.001) , while the validation group showed an AUC of 0.944 (95%CI: 0.872-0.988, P<0.001) .

Pyrotinib significantly improves therapeutic efficacy in patients with HER-2-positive breast cancer. The prognostic prediction model developed in this study can identify patients requiring intensified adjuvant therapy.