In breast cancer, sentinel lymph node biopsy is contraindicated in which of the following clinical scenarios?

Explanation

## Sentinel Lymph Node Biopsy (SLNB) in Breast Cancer — Indications and Contraindications **Key Point:** SLNB is the standard of care for axillary staging in clinically node-negative breast cancer. However, certain clinical scenarios preclude its use. ### Indications for SLNB - Clinically node-negative (cN0) breast cancer - Early-stage disease (T1–T3) - Ductal carcinoma in situ (DCIS) with invasive component - Neoadjuvant therapy responders (if cN0 at presentation) ### Absolute Contraindications to SLNB | Contraindication | Reason | |------------------|--------| | **Prior axillary dissection (ipsilateral)** | Disrupts lymphatic drainage; sentinel node identification unreliable | | **Clinically positive nodes (cN1+)** | Requires completion axillary dissection; SLNB insufficient | | **Inflammatory breast cancer** | Requires systemic therapy + mastectomy; SLNB not indicated | | **Pregnancy (relative)** | Radiotracer use is relative contraindication; blue dye alone is safe | **High-Yield:** Prior axillary dissection on the ipsilateral side is an **absolute contraindication** because the lymphatic drainage pathways are disrupted, making sentinel node identification impossible or unreliable. This is a high-yield fact for NEET PG. **Clinical Pearl:** In pregnancy, SLNB using blue dye alone (without radiotracer) is safe and acceptable. The radiotracer is the relative concern, not the procedure itself. **Warning:** Do NOT confuse prior axillary dissection (contraindication) with prior breast surgery on the contralateral side (not a contraindication). SLNB can still be performed on the opposite breast.