Inguinal Sentinel Node Dissection versus Standard Inguinal Node Dissection in Patients With Vulvar Cancer: A Comparison of the Size of Metastasis Detected in Inguinal Lymph Nodes

Abstract

The conventional treatment for vulvar cancer is radical vulvectomy accompanied by en bloc inguinofemoral lymphadenectomy, but chronic lymphedema and wound breakdown both occur in more than half of operated patients. These problems are less prevalent when limited surgery is carried out, consisting of wide local excision and dissection of superficial groin nodes. Dissection of the inguinal sentinel lymph node (SLN) reportedly is a highly sensitive means of detecting metastases in the inguinal nodes. This retrospective study comprised 336 inguinal node dissections in patients with primary vulvar malignancies. Complete inguinal lymph node dissection was carried out in 284 women and SLN dissection in 52. All participants had nonpalpable inguinal nodes no larger than 1 cm in size. The investigators hypothesized that SLN dissection would disclose smaller metastases in impalpable inguinal nodes. Lymphoscintigraphy was used to detect the SLN after intradermal peritumoral injection of technetium-99m-labeled sulfur colloid. Isosulfan blue or methylene blue was injected at the same sites before dissecting the lymph nodes and radically excising the vulvar tumor. Inguinal node metastases were discovered in 58 patients, 30 of whom had no clinical evidence of nodal metastasis. The size of inguinal node metastases was compared in 7 groins having metastases detected by SLN dissection and 23 undergoing CND. Metastatic foci averaged 2.5 mm in the SLN group and 4.35 mm in the CND group-not a significant difference. There was, however, a significant difference in the size of cell clusters, smaller clusters being present in women having SLN dissection. A majority of women in both groups had stage III vulvar cancer. The size of primary vulvar tumors did not differ significantly in the SLN and CND groups. In women operated on for vulvar cancer, SLN dissection may detect smaller foci of disease than traditional CND. SLN with ultrastaging can detect isolated micrometastases and smaller clusters of metastatic cells. Whether this is clinically relevant remains to be determined.