Adjuvant chemotherapy in small node-negative triple-negative breast cancer

Area of Science:

• Oncology
• Clinical Research
• Breast Cancer Treatment

Background:

• Adjuvant chemotherapy recommendations for early-stage triple-negative breast cancer (TNBC) lack consensus due to limited randomized trial data.
• Population-based studies are crucial for evaluating long-term outcomes in pT1N0M0 TNBC.

Purpose of the Study:

• To assess the association between adjuvant chemotherapy and long-term survival in a large cohort of patients with pT1N0M0 TNBC.
• To investigate how tumor size influences the effectiveness of adjuvant chemotherapy in this patient group.

Main Methods:

• Utilized the Netherlands Cancer Registry to identify 4366 patients diagnosed with pT1N0M0 TNBC between 2005 and 2016.
• Employed multivariable Cox regression and propensity score weighting to analyze the impact of chemotherapy on breast cancer-specific survival (BCSS) and overall survival (OS).
• Adjusted for patient, tumor, and treatment characteristics to control for confounding factors.

Main Results:

• Adjuvant chemotherapy was administered to 53% of patients, who often presented with more unfavorable baseline characteristics.
• After adjustment, chemotherapy was linked to improved BCSS (aHR=0.65) and OS.
• The survival benefit varied significantly by tumor size, with a notable positive association in pT1c tumors and a potential negative association in pT1a/pT1b tumors (p-interaction=0.02).

Conclusions:

• Adjuvant chemotherapy is associated with improved BCSS and OS in patients with pT1N0M0 TNBC.
• The benefits of adjuvant chemotherapy are most pronounced in larger tumors (pT1c) and may not outweigh potential harms in smaller tumors (pT1a/pT1b).
• These findings highlight the importance of considering tumor size when making treatment decisions for early-stage TNBC.