Prognostic Role of Lymph Node Metastases in Vulvar Cancer and Implications for Adjuvant Treatment

Abstract

Lymph node metastases are the most important prognostic factor for recurrence and survival in vulvar cancer. However, information regarding the impact of the number of positive nodes in vulvar cancer is inconsistent, and so are recommendations when to apply adjuvant radiotherapy. One hundred fifty-seven consecutive patients with primary squamous cell cancer of the vulva treated at our center were analyzed. All patients underwent primary surgery by triple incision resulting in complete tumor resection. Median age was 61 years; 49 patients (31%) had lymph node metastases; 21 patients had 1, 13 had 2, and 15 had more than 2 positive lymph nodes. Thirty-two percent of the patients received adjuvant radiotherapy. The risk of lymph node metastases increased with age, greater tumor size, deeper invasion, and higher tumor grade. Median follow-up was 36 months; 23 patients (14.6%) developed disease recurrence (61% vulva, 35% groins, and 4% both). Compared with node-negative patients, survival in all node-positive patients was significantly impaired (P < 0.001; disease-free patients after 2 years: 88% in node-negative patients; 60%, 43%, and 29% in patients with 1, 2, and >2 affected nodes, respectively), whereas no significant difference between the node-positive subgroups could be demonstrated regarding disease-free survival. In multivariate analysis, lymph node status remained the most important prognostic factor regarding disease-free survival, but the effect of positive nodes differed significantly dependent on adjuvant treatment (P = 0.001). In patients without adjuvant radiotherapy to the groins/pelvis, the number of metastatic nodes was highly relevant for prognosis (hazard ratio, 1.752; P < 0.001), whereas this effect disappeared in patients who were treated with adjuvant radiotherapy (hazard ratio, 0.972; P = 0.828). The negative impact of lymph node metastases is already evident in patients with only 1 affected lymph node. In patients receiving adjuvant radiotherapy, the negative effect of additional lymph node metastases is reduced; adjuvant treatment might therefore be beneficial in patients with only 1 positive node.