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

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

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.

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.

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.