Pathology, Immunohistochemistry, and SLN Biopsy

• The prognostic significance of sentinel lymph node (SLN) disease detected on immunohistochemistry (IHC) has been widely debated and results from two  studies indicate that SLN micrometastases detected by IHC staining are clinically insignificant and routine use of IHC can be abandoned.

  • In the ACOSOG Z0010 and National Surgical Adjuvant Breast and Bowel Protocol (NSABP) B-32 trials:

    • All patients were treated on the basis of H&E SLN stains only.

      • To control for treatment bias, clinicians and patients were blinded to the results of IHC staining.

    • In ACOSOG Z0010:

      • A prospective observational study of SLN biopsy

      • Occult metastases were found by IHC in 8.9% of 3945 patients who were SLN-negative by H&E:

        • 5-year survival was not different between those patients who were H&E negative and IHC negative, and those who were H&E negative and IHC positive:

          • 95.8% vs 95.1% (P = 0.53)

    • In NSABP B-32:

      • A prospective randomized study of SLN biopsy plus ALND vs SLN biopsy alone (with ALND limited to SLN-positive patients)

      • Occult metastases were found by IHC in 15.9% of 3887 H&E-negative patients:

        • Although overall, disease-free and distant disease–free survival were significantly worse for IHC-positive than for IHC-negative patients:

          • The absolute difference in overall survival was only 1.2%:

            • 94.6% vs 95.8% (P = 0.03).

• The results of the ACOSOG Z0010 and NSABP B-32 trials suggest that SLN micrometastases found only by IHC are clinically insignificant and that IHC staining of SLNs is unnecessary:

  • Therefore, routine use of IHC staining of SLNs is not recommended and should be limited to selective use at the discretion of the pathologist.

  • In addition, intraoperative frozen-section analysis of the SLN can be avoided if clinical suspicion of nodal involvement is low and the patient otherwise meets the entry criteria for the Z-11 trial.

    • The data is fairly clear for the above recommendations.

Rodrigo Arrangoiz MS, MD, FACS a surgical oncologist and is a member of Sociedad Quirúrgica S.C at the America British CowdrayMedical Center in Mexico City:

• He is an expert in the management of breast cancer

Training:

• General surgery:

• Michigan State University:

• 2004 al 2010

• Surgical Oncology / Head and Neck Surgery / Endocrine Surgery:

• Fox Chase Cancer Center (Filadelfia):

• 2010 al 2012

• Masters in Science (Clinical research for health professionals):

• Drexel University (Filadelfia):

• 2010 al 2012

• Surgical Oncology / Head and Neck Surgery / Endocrine Surgery:

• IFHNOS / Memorial Sloan Kettering Cancer Center:

• 2014 al 2016