Objective: To investigate the diagnostic accuracy of the sentinel node procedure in patients with vulvar cancer, a multicenter study was launched in Germany in 2003 involving 7 oncology centers.
Patients and methods: Between 2003 and 2006, 127 women with primary T1-T3 vulvar cancer were entered in the study and treated with sentinel node removal after application of (99m)Technetium labeled nanocolloid and/or blue dye. Subsequently, in all women a complete inguinofemoral lymphadenectomy and the adequate vulvar operation were performed. Sentinel lymph nodes were examined by routine pathologic examination (H&E), followed by step-sectioning and immunhistochemistry if negative.
Results: The sentinel node procedure was successful in 125 out of 127 cases, in 2 cases no sentinel nodes were detected. 21 patients received unilateral lymphadenectomy, 103 women were operated on both groins. In 39 women out of 127, positive lymph nodes in one or both groins were identified (30.7%). In 36 women, the sentinel nodes were also positive (sensitivity 92.3%). We had three cases with a false negative sentinel node (false negative rate: 7.7%), all of these women presenting with tumors in midline position. One tumor was a T1 tumor (10 mm), 2 tumors being classified as T2 (40 and 56 mm, respectively). In one additional case (18 mm T1 tumor, midline position), the sentinel was positive in the right groin, but false negative on the left side.
Conclusions: This study shows that identification of SLN in squamous cell cancer of the vulva is feasible, however not highly accurate depending on tumor localization and size. The false negative rate seems to be acceptable if the procedure is restricted to stage 1 tumors with clinically negative lymph node status. Tumors situated in or close to the midline seem to be less suitable for this procedure. Implementation of SLNB into clinical practice should be performed with care and only by experienced teams as to avoid preventable groin relapses.