ObjectiveTo compare clinicopathologic characteristics and prognosis between HER2-low and HER2-negative patients with stage T1 and T2 triple-negative breast cancer (TNBC). MethodsThe patients with stage T1 and T2 TNBC treated at the Affiliated Hospital of Southwest Medical University from June 2019 to June 2021 were retrospectively collected. The clinicopathologic features were analyzed using two-sided Chi-square test. Multivariate binary logistic regression identified risk factors for 3-year postoperative recurrence/metastasis. Kaplan-Meier survival curves was used to compare 3-year disease-free survival (DFS) between the TNBC patients with HER2-low and HER2-negative. The statistical significance was defined as α=0.05. ResultsA total of 126 patients with stage T1 and T2 TNBC were enrolled, 63 were HER2-negative and 63 HER2-low. Compared with HER2-negative patients, HER2-low patients demonstrated significantly higher proportions of: Age ≥50 years old, postmenopausal status, lymphovascular invasion (P<0.05). HER2 expression level and axillary lymph node metastasis were the independent risk factors for 3-year postoperative recurrence/metastasis in the patients with stage T1 and T2 TNBC (P<0.05). The patients with HER2-low expressing demonstrated significantly inferior 3-year DFS compared to patients with HER2-negative (χ2=7.741, P=0.005). ConclusionsFindings of this study suggest that among patients with stage T1 and T2 TNBC, HER2-low expression is associated with advanced age (≥50 years), menopausal status, and lymphovascular invasion. It may serve as an indicator of a distinct biologic subgroup or unfavorable pathologic characteristics. Patients with stage T1 and T2 TNBC who have HER2-low expression and positive axillary lymph node metastasis require close monitoring for recurrence/metastasis within 3 years postoperatively.
ObjectiveTo investigate the factors influencing pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) in patients with luminal breast cancer (LBC), and to construct and validate a nomogram-based predictive model. MethodsPatients with LBC who received NACT at the Affiliated Hospital of Southwest Medical University between January 2021 and February 2025 were retrospectively enrolled. Patients were randomly divided into training cohort (n=205) and validation cohort (n=87) by a ratio of 7∶3. Multivariate logistic regression analyses was performed in the training cohort, and a nomogram was developed based on the multivariate results. Model discrimination was evaluated using receiver operating characteristic (ROC) curves, calibration was assessed using calibration plots, and clinical utility was examined using decision curve analysis (DCA) in both cohorts. ResultsMultivariate logistic regression analysis in the training cohort showed that clinical tumor stage 4 [OR=0.018, 95%CI (0.001, 0.312), P=0.006], estrogen receptor expression>37.5% [OR=0.275, 95%CI (0.095, 0.798), P=0.018], and Ki-67 index>47.5% [OR=4.134, 95%CI (1.480, 11.544), P=0.007] were independent factors associated with pCR after NACT in LBC patients. A nomogram was constructed accordingly. The area under the ROC curve of the predictive model was 0.834 in the training cohort and 0.785 in the validation cohort. Calibration curves and Hosmer-Lemeshow tests demonstrated good predictive performance of the model in both cohorts (χ2=1.610, P=0.807; χ2=1.859, P=0.762). DCA indicated that the nomogram provided the greatest net benefit when the threshold probability ranged from 0% to 50% in both cohorts. ConclusionsClinical tumor stage, estrogen receptor expression level, and Ki-67 index were independent predictors of pCR after NACT in LBC patients. The nomogram constructed based on these factors showed good predictive performance in both the training and validation cohorts.