Axillary staging based on molecular analysis: Results of the B-CLOSER-II study

Area of Science:

• Oncology
• Molecular Biology
• Surgical Pathology

Background:

• Axillary lymph node staging (pN) is crucial for early-stage breast cancer prognosis.
• The Z0011 trial has led to reduced lymph node dissection, increasing reliance on accurate staging methods.
• One-step nucleic acid amplification (OSNA) offers automated molecular detection of cytokeratin 19 mRNA for sentinel lymph node (SLN) metastasis.

Purpose of the Study:

• Compare histological and molecular staging methods after complete axillary lymph node dissection (cALND).
• Determine if molecular axillary staging impacts patient survival.
• Evaluate the predictive and prognostic value of total tumor load in ALND (AD-TTL) and in all positive nodes (G-TTL).

Main Methods:

• Collected axillary lymph nodes from 102 breast cancer patients with confirmed axillary involvement or positive SLN.
• Processed the central 1-mm portion of non-SLNs for histological (hematoxylin-eosin) analysis.
• Analyzed remaining non-SLN tissue using OSNA for molecular detection.

Main Results:

• OSNA identified positive non-SLNs in 70.6% of patients, significantly higher than histology (52%, p < 0.01).
• Molecular methods would have altered staging for 13 patients (p < 0.01), but without prognostic change.
• Both AD-TTL and G-TTL were predictive of recurrence and mortality.

Conclusions:

• Histological examination significantly underestimates axillary lymph node metastasis frequency compared to molecular detection (OSNA).
• Despite increased detection of metastases via molecular methods, the change in pN did not clinically affect patient survival.