Breast cancer progression when definitive surgery is delayed.

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• The COVID-19 pandemic necessitated resource conservation, leading to proposals for deferring breast cancer surgeries.
• The potential for breast cancer progression during delayed treatment remains largely uncharacterized.

Purpose of the Study:

• To investigate breast cancer tumor growth during observation periods before definitive surgery.
• To identify clinical and pathological factors predicting tumor progression in stage I-III breast cancers.

Main Methods:

• Assessed size differences between clinical diagnosis and final pathology in 315 stage I-III breast cancer patients.
• Categorized patients into groups based on diagnosis-to-surgery intervals (≤60, 61-120, >120 days).
• Estimated specific growth rates to quantify tumor progression.

Main Results:

• Tumor growth was observed in 12% and 17% of tumors with delays of 61-120 and >120 days, respectively.
• Significantly higher growth rates were noted for tumors >2 cm and in node-positive patients.
• Luminal B breast cancers exhibited significantly greater growth rates compared to luminal A.
• No nodal progression was observed with delayed surgery; <20% of tumors showed size progression.

Conclusions:

• Breast cancer tumor growth can occur during delayed surgery, particularly in larger and node-positive tumors.
• Luminal B phenotype is a strong predictor of tumor growth at diagnosis.
• Prioritizing luminal B breast cancer for surgery may be necessary during resource limitations.