Sentinel lymph node metastasis in microinvasive breast cancer

Area of Science:

• Oncology
• Surgical Pathology
• Breast Cancer Research

Background:

• Ductal carcinoma in situ with microinvasion (DCISM) is a distinct pathological entity with metastatic potential.
• Current controversy exists regarding complete axillary dissection (CAD) for DCISM staging due to morbidity and low incidence of axillary involvement.
• Sentinel lymph node biopsy (SLNB) offers a less invasive alternative for axillary staging.

Purpose of the Study:

• To evaluate the utility of SLNB in staging the axilla for patients diagnosed with DCISM.
• To determine the incidence of axillary metastasis in DCISM patients undergoing SLNB.
• To assess whether SLNB can obviate the need for CAD in DCISM.

Main Methods:

• Retrospective analysis of 41 patients with DCISM who underwent SLNB between March 1996 and December 2002.
• Inclusion criteria: invasive breast carcinoma patients undergoing SLNB.
• Data collected on SLN metastasis and comparison with CAD findings.

Main Results:

• Metastasis was detected in the SLN of 4 out of 41 (9.7%) DCISM patients.
• Two of these patients had only micrometastasis in the sentinel lymph node.
• In three patients, the SLN was the only positive node identified after complete axillary dissection.

Conclusions:

• SLNB is a reliable procedure for staging the axilla in DCISM patients.
• SLNB can identify nodal micrometastasis, potentially avoiding the morbidity of complete axillary dissection (CAD).
• Complete axillary dissection may not be mandatory if only micrometastatic disease is found in the SLN, emphasizing informed consent.