Adjuvant chemotherapy and survival among patients 70 years of age and younger with node-negative breast cancer and the 21-gene recurrence score of 26-30

• Published in: Breast cancer research : BCR 2019-10, Vol.21 (1), p.110-110, Article 110
• Main Authors: Park, Seho, Han, Yunan, Liu, Ying, Toriola, Adetunji T, Peterson, Lindsay L, Colditz, Graham A, Kim, Seung Il, Cho, Young Up, Park, Byeong-Woo, Park, Yikyung
• Format: Article
• Language: English
• Subjects: 21-gene recurrence score; Adjuvant chemotherapy; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - genetics; Breast Neoplasms - metabolism; Cancer genetics; Cancer therapies; Cancer treatment; Chemotherapy; Chemotherapy, Adjuvant; Datasets; Diagnosis; Epidemiology; Epidermal growth factor; Epidermal growth factors; ErbB-2 protein; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genes; Hormones; Humans; Kaplan-Meier Estimate; Lymphatic Metastasis; Lymphatic system; Marital status; Medical diagnosis; Menopause; Middle Aged; Mortality; Neoplasm Recurrence, Local; Patients; Prognosis; Radiation therapy; Receptor, ErbB-2 - metabolism; Receptors, Estrogen - metabolism; Receptors, Progesterone - metabolism; Retirement benefits; Retrospective Studies; SEER Program - statistics & numerical data; Surveillance; Survival; Tumors
• ISSN: 1465-542X; 1465-5411; 1465-542X
• DOI: 10.1186/s13058-019-1190-4

The benefits of chemotherapy in node-negative, hormone receptor-positive, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients with the 21-gene recurrence score (RS) of 18-30, particularly those with RS 26-30, are not known. Using the Surveillance, Epidemiology, and End Results (SEER) data, we retrospectively identified 29,137 breast cancer patients with the 21-gene RS of 18-30 diagnosed between 2004 and 2015. Mortality risks according to the RS and chemotherapy use were compared by the Kaplan-Meier method and Cox's proportional hazards model. Among the breast cancer patients with the RS 18-30, 21% of them had RS 26-30. Compared to breast cancer patients with RS 18-25, patients with RS 26-30 had more aggressive tumor characteristics and chemotherapy use and increased risk of breast cancer-specific mortality and overall mortality. In breast cancer patients who were aged ≤ 70 years and had RS of 26-30, chemotherapy administration was associated with a 32% lower risk of breast cancer-specific mortality (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.47-0.99) and a 42% lower risk of overall mortality (HR, 0.58; 95% CI, 0.44-0.76). Survival benefits were most pronounced in breast cancer patients who were younger or had grade III tumor. The 21-gene RS of 18-30 showed heterogeneous outcomes, and the RS 26-30 was a significant prognostic factor for an increased risk of mortality. Adjuvant chemotherapy could improve the survival of node-negative, hormone receptor-positive, and HER2-negative breast cancer patients with the 21-gene RS 26-30 and should be considered for patients, especially younger patients or patients with high-grade tumors.