Sentinel Lymph Node Procedure Is Highly Accurate in Squamous Cell Carcinoma of the Vulva

abstract & commentary

Synopsis: Sentinel lymph node procedure with the combined technique is highly accurate in predicting the inguinofemoral lymph node status in patients with early-stage vulvar cancer.

Source: de Hullu JA, et al. J Clin Oncol 2000;18: 2811-2816.

In a recent issue of the Journal of Clinical Oncology, de Hullu and colleagues reported 59 patients with primary vulvar cancer who entered a two-center prospective study. All patients underwent sentinel lymph node procedure with the combined technique (preoperative lymphoscintigraphy with technetium-99m-labeled nanocolloid and intraoperative blue dye). Radical excision of the primary tumor with uni- or bilateral inguinofemoral lymphadenectomy was performed subsequently. Sentinel lymph nodes and lymphadenectomy specimens were sent for histopathologic examination separately. Sentinel lymph nodes, negative at the time of routine pathologic examination, were re-examined with step sectioning and immunohistochemistry. In 59 patients, 107 inguinofemoral lymphadenectomies were performed (11 unilateral and 48 bilateral). All sentinel lymph nodes, as observed on preoperative lymphoscintigram, were identified successfully intraoperatively. Routine histopathologic examination showed lymph node metastases in 27 groins, all of which were detected by the sentinel lymph node procedure. The negative predictive value for a negative sentinel lymph node was 100%. Step sectioning and immunohistochemistry showed four additional metastases in 102 sentinel lymph nodes that were negative at the time of routine histopathologic examination. de Hullu et al concluded that sentinel lymph node procedure with the combined technique is highly accurate in predicting the inguinofemoral lymph node status in patients with early-stage vulvar cancer. They further concluded that future trials should focus on the safe clinical implementation of the sentinel lymph node procedure in these patients. Step sectioning and immunohistochemistry slightly increase the sensitivity of detecting metastases in sentinel lymph nodes and should be included in these trials.

Comment by David M. Gershenson, MD

The treatment of invasive vulvar cancer has changed dramatically in the past two decades. Until the mid-1980s or so (and even to the present time in a few centers), radical vulvectomy and bilateral inguinofemoral lymphadenectomy was standard treatment. Beginning in the late 1970s, a few groups began to use less radical surgical treatment—wide radical excision (or hemivulvectomy) for the primary lesion. In addition, optimizing our knowledge of lymphatic drainage of the vulva, for unilateral vulvar lesions, unilateral inguinal lymphadenectomy was practiced. Other advances include the practice of superficial inguinal lymphadenectomy rather than total lymphadenectomy. In 1994, our group at M.D. Anderson Cancer Center was the first to report the use of sentinel node mapping in the management of vulvar cancer. At that time, we were only using the intraoperative blue dye injection approach. At present, we are also using the lymphoscintigraphy technique described in this paper. Based on our work, the Gynecologic Oncology Group is now conducting a prospective clinical trial to validate the use of lymphatic mapping in vulvar cancer. This paper represents an important contribution to the literature. As we gain more knowledge and experience with these techniques, the radicality of surgical treatment of vulvar cancer will be reduced even further.