Axillary Pathologic Complete Response as a Stronger Prognostic Marker than Breast pCR in Clinically Node-Positive...

Area of Science:

• Oncology
• Breast Cancer Research
• Clinical Therapeutics

Background:

• Pathologic complete response (pCR) post-neoadjuvant systemic therapy (NAST) is linked to improved survival in breast cancer.
• The comparative prognostic significance of achieving pCR in the breast versus the axilla for initially node-positive disease remains uncertain.

Purpose of the Study:

• To evaluate the relative prognostic value of breast and axillary pCR after NAST in patients with clinically node-positive stage II-III breast cancer.
• To assess the impact of different breast-axilla response patterns on invasive disease-free survival (IDFS) and overall survival (OS).

Main Methods:

• Analysis of 455 patients with clinically node-positive stage II-III breast cancer treated with NAST between 2010-2022.
• Patients categorized by response: both-site pCR, breast-only pCR, axilla-only pCR, or neither pCR.
• Multivariable Cox models used to assess prognostic associations with IDFS and OS, adjusted for covariates.

Main Results:

• Axillary pCR demonstrated numerically stronger prognostic associations for both IDFS and OS compared to breast pCR in head-to-head analysis.
• Achieving pCR in both sites (89% 5-year IDFS) and one site (77% IDFS for axilla-only) conferred favorable outcomes.
• Breast-only pCR (65% 5-year IDFS) did not show a statistically significant survival benefit in this underpowered subgroup.

Conclusions:

• In node-positive breast cancer treated with NAST, axillary pCR may hold stronger prognostic significance than breast pCR.
• Post-neoadjuvant nodal status is a potential factor for refining risk stratification.
• These findings can inform adjuvant treatment planning for breast cancer patients.