Is the node of Cloquet the sentinel node for the iliac/obturator node group?

Area of Science:

• Oncology
• Surgical Oncology
• Melanoma Research

Background:

• Ilioinguinal lymphadenectomy is debated for metastatic melanoma due to perceived poor prognosis with deep nodal involvement.
• Survival rates of 30% are reported post-lymphadenectomy, with potential improvement from adjuvant therapies.
• Selective pelvic lymphadenectomy requires accurate prediction of deep nodal metastasis.

Purpose of the Study:

• To test the hypothesis that the node of Cloquet accurately reflects the pathologic status of iliac/obturator nodes.
• To determine if the node of Cloquet can guide selective deep pelvic lymphadenectomy.

Main Methods:

• Retrospective review of 691 patients with primary cutaneous melanoma undergoing ilioinguinal lymphadenectomy (1972-1998).
• Analysis of 68 patients with positive inguinal/pelvic nodes, focusing on the association between Cloquet's node status and deep pelvic node metastasis.
• Immunohistochemical analysis (S-100, HMB45) of selected Cloquet's nodes.

Main Results:

• Tumor-positive deep nodes were found in 67% of patients with a positive Cloquet's node vs. 23% with a negative node (P=0.0019).
• Immunohistochemistry increased Cloquet's node sensitivity for predicting deep nodal metastases from 71% to 82%.
• Odds ratio for positive deep nodes increased from 6.8 to 12.4 with immunohistochemistry; predictive values improved.

Conclusions:

• The tumor status of the node of Cloquet significantly correlates with iliac/obturator node status, especially with immunohistochemical analysis.
• The node of Cloquet functions as a sentinel node for deep pelvic lymphatic drainage in melanoma.
• This supports selective pelvic lymphadenectomy based on Cloquet's node examination.