Comparison of clinical characteristics and pathologic complete response (pCR) rate after neoadjuvant chemotherapy in women under 35 years and older women with breast cancer

Abstract

Purpose Age has been confirmed to be a very aggressive biological factor associated with the poor prognosis of breast cancer (BC) patients. But the understanding of young women's breast cancer (YWBC) is scarce. This study compares and evaluates the clinical characteristics and pCR rate after neoadjuvant chemotherapy (NAC) in YWBC and older women with BC. Patients and methods We retrospectively analyzed the clinicopathological data, molecular subtypes, chemotherapy regimen, and pCR rates of 1419 non-metastatic BC patients from the Affiliated Cancer Hospital of Harbin Medical University from January 1, 2012, to December 31, 2019. Patients were classified according to age (35 years old and below vs above 35 years old) with the clinical parameters. Categorical data were compared using the chi-square test and Fisher's exact test for multivariate data using Logistic regression models. Any predictor variable with P < 0.05 in the univariate analysis was included in the multivariate regression analysis to study the relationship between different age groups and pCR. Results A total of 879 patients in this study were eligible for analysis, and 71(8.1%) female patients were ≤ 35 years old. YWBC were more likely to get pCR (25.4%vs15.6%, P = 0.033). The proportion of patients with a higher clinical stage was higher. Compared with elderly patients, YWBC patients were more likely to undergo breast-conserving surgery (BCS), multivariate analyses found similar results in different age groups, and more patients with HER-2 positive and triple-negative breast cancer (TNBC). In the whole group, Age, PR expression, HER-2 expression, KI67 expression, and clinical stage were the independent predictors of pCR after NAC in BC patients (P < 0.05). Conclusion Our study found that age is the main factor affecting the achievement of pCR in patients with BC. YWBC has a higher clinical stage and a high proportion of HER-2 positive patients, which is the leading cause of poor prognosis. YWBC has a higher effect on chemotherapy. We need to pay more attention to this group and achieve individualized treatment, which will help us treat BC better and provide new targets and blueprints for our clinical therapy.