From the Guidelines
Sentinel lymph node biopsy (SLNB) is recommended for vulvar cancers with invasion depth greater than 1mm or FIGO stage IB and above, specifically for patients with primary tumors <4cm in diameter and no previous vulvar surgery that may have impacted lymphatic flow to the inguinal region, as stated in the most recent guidelines 1.
Key Factors for SLNB
- Primary tumor size: <4cm in diameter
- Invasion depth: >1mm
- No previous vulvar surgery that may have impacted lymphatic flow to the inguinal region
- Clinically negative groin examination and imaging
Rationale for SLNB
The procedure is indicated to accurately stage the disease while avoiding the significant morbidity associated with complete inguinofemoral lymphadenectomy, including lymphedema, wound complications, and sensory deficits, as supported by studies 1.
Procedure Details
- SLNB should be performed by a high-volume SLN surgeon
- Use of dual tracers (radiocolloid and dye) is recommended for increased sensitivity of SLN detection
- The procedure should be performed prior to the excision of the vulvar tumor to avoid disrupting the lymphatic network
Management of Positive SLNs
- Complete inguinofemoral lymphadenectomy is recommended if an ipsilateral SLN is not detected
- The management of positive SLNs is currently being evaluated and may include performance of complete inguinofemoral lymphadenectomy and/or administration of adjuvant radiation to the affected groin(s), as discussed in the guidelines 1.
From the Research
Pathological or Histological Factors for Sentinel Lymph Node Biopsy in Vulvar Cancer
The decision to perform a sentinel lymph node biopsy (SLNB) in vulvar cancer is based on several pathological or histological factors, including:
- Tumor size: Patients with unifocal tumors <4 cm are considered suitable for SLNB 2, 3
- Tumor location: Lateralized tumors with a unilateral metastatic sentinel lymph node may allow for omission of contralateral inguinofemoral lymph node dissection (IFLD) 4, 5
- Node status: Clinically non-suspicious nodes in the groin are a prerequisite for SLNB 2
- Presence of micrometastases: Patients with micrometastases in the sentinel lymph node may be treated with radiotherapy instead of IFLD 4, 5
Indications for Sentinel Lymph Node Biopsy
The indications for SLNB in vulvar cancer are:
- Early-stage vulvar cancer with unifocal primary tumor <4 cm and clinically negative inguinal lymph nodes 2, 3
- Selected patients with larger tumors or multifocal tumors, although this is still being investigated 5
- Patients with recurrent disease, although this is still being investigated 5
Pathologic Workup of Sentinel Lymph Node
The pathologic workup of the sentinel lymph node is crucial for accurate detection of metastases. However, there is currently no standardized protocol for the pathologic workup of the sentinel lymph node, which may lead to discrepancies in detection of metastases between institutes using different methods 5. New techniques, such as one-step nucleic amplification, may have potential in accurately detecting metastases in vulvar squamous cell carcinoma (VSCC), but have not yet been investigated 5.