Point: sentinel lymph node biopsy is indicated for patients with DCIS

Area of Science:

• Oncology
• Surgical Pathology

Background:

• Sentinel lymph node (SLN) biopsy is standard for invasive breast cancer but debated for ductal carcinoma in situ (DCIS).
• DCIS typically has excellent survival, but recent studies show 6-13% of patients have SLN metastases.
• Pathologic sampling errors in DCIS diagnosis are common, with 10-21% of definitive surgeries revealing invasive cancer.

Purpose of the Study:

• To evaluate the significance of SLN metastases in DCIS patients.
• To propose a new understanding of DCIS patient stratification based on SLN status.
• To determine the indications for SLN biopsy in DCIS.

Main Methods:

• Review of recent DCIS series reporting SLN metastases.
• Analysis of the prognostic significance of micrometastases detected by serial sectioning.
• Comparison of SLN biopsy findings with outcomes of definitive surgery and long-term survival.

Main Results:

• Positive SLNs in DCIS, often micrometastases, are increasingly recognized as prognostically significant.
• Patients with positive SLNs may have occult invasive cancer, impacting long-term disease-free survival (DDFS).
• A proposed two-tier stratification suggests 90% of DCIS patients have true in situ disease with excellent DDFS, while 10% may have occult invasion with lower DDFS.

Conclusions:

• SLN biopsy may be a more sensitive test for occult invasion in DCIS than current breast examination methods.
• SLN biopsy is indicated for DCIS patients with potential underlying invasive cancer, particularly those undergoing mastectomy.
• Further research is needed to develop predictive models for identifying DCIS patients who would benefit from SLN biopsy.