The accuracy of the sentinel lymph node concept in early stage squamous cell vulvar carcinoma

Abstract

Objective: The purpose of the study was to determine the feasibility and accuracy of the sentinel lymph node (SLN) identification in vulvar carcinoma patients.

Methods: Sixty-two patients with clinical early stage vulvar cancer underwent SLN detection procedure, followed by a complete inguinofemoral lymphadenectomy. The SLN was identified intraoperatively using lymphoscintigraphy with technetium-99m as well as patent blue V staining. The resected lymph nodes (LN) were submitted for histological examination by hematoxylin-eosin staining (H-E) and cytokeratin immunohistochemistry (IHC) and examined by the reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

Results: A total of 109 inguinal LN were dissected in 56 patients. SLNs were identified in 76% groins with patent blue V and in 99% with the use of Tc-99m. The accuracy differed significantly (p<0.0001). An H-E examination combined with IHC revealed 7 false-negative SLNs. The sensitivity of this method was 73% (95% CI, 64% to 81%) and the negative predictive value for a negative SLN finding was 92% (95% CI, 87% to 97%). The RT-PCR assay showed 8 false-negative SLNs. The sensitivity of the RT-PCR-based assay was 83% (95% CI, 75% to 90%) and the negative predictive value for a negative SLN was 88% (95% CI, 82% to 94%). The two diagnostic methods were found not to differ significantly.

Conclusions: In SLN mapping, the Tc-99m colloid lymphoscintigraphy is superior to the blue dye staining. Our data do not support the concept of the SLN identification as a highly accurate procedure in predicting the inguinofemoral LN status in patients with early stage vulvar cancer.