Noninvasive detection of inguinofemoral lymph node metastases in squamous cell cancer of the vulva by L-

In the majority of patients with early stage squamous cell cancer (SCC) of the vulva, an inguinofemoral lymphadenectomy is performed (in retrospect) for diagnostic reasons: exclusion of inguinofemoral lymph node metastases. The morbidity of this procedure, however, is significant. The aim of the present study was to evaluate noninvasive detection of inguinofemoral lymph node metastases by positron emission tomography (PET) using L-[1-11C]-tyrosine (TYR) as tracer. In patients with SCC of the vulva, scheduled for resection of the primary tumor and uni- or bilateral inguinofemoral lymphadenectomy, results of preoperative palpation of the groins and TYR-PET imaging were compared with histopathology. PET imaging was performed using two different methods. In a first group (n = 16), nonattenuation corrected 'whole body' scans were performed, and in a second group (n = 9), attenuation corrected static emission scans. Sensitivity, specificity, accuracy, and positive and negative predictive value for palpation were 62%, 89%, 82%, 67%, and 87% per groin. Sensitivity, specificity, accuracy, and positive and negative predictive value for TYR-PET were calculated for the two methodologies separately and overall. There were no significant differences. Overall values were 53%, 95%, 94%, 33%, and 98% per lymph node and 75%, 62%, 65%, 41% and 88% per groin. Detection of inguinofemoral lymph node metastases by TYR-PET is not superior to palpation. Neither palpation nor TYR-PET is able to adequately predict or exclude presence of inguinofemoral lymph node metastases in patients with SCC of the vulva.