Objective: To evaluate the level of epidermal growth factor receptor (EGF-R) expression in vulvar malignancies and to determine if a correlation exists between EGF-R levels and metastasis or patient survival.
Methods: All patients with a diagnosis of invasive squamous cell carcinoma of the vulva who were treated at our institution with a primary radical vulvectomy and inguinal lymph node dissection from 1983 to 1993 were eligible for the study. Sixty-one patients with available tissue blocks of benign vulvar epithelium, the primary malignant vulvar lesion, and groin node metastasis (when positive) were included in the study. Semiquantitative EGF-R expression was determined in a blinded fashion utilizing immunohistochemical staining of appropriate tissue samples. Survival was calculated utilizing Kaplan-Meier life table analysis based upon disease-free survival.
Results: A significant increase (P < 0.001) in mean EGF-R levels was demonstrated in the primary tumor (67%) versus benign vulvar epithelium (31%). In the 14 patients with lymph node metastasis, the mean EGF-R level in the primary tumor was 65% versus 88% in the metastatic lesion (P < 0.001). The likelihood of lymph node metastasis was elevated in those patients with a benign tissue EGF-R level > or =40% (P < 0.03) and in those patients with a primary tumor EGF-R level > or =90% (P < 0.025). Life table analysis revealed a cumulative disease-free survival of 45% for all patients. Disease-free survival in those patients with EGF-R levels > or =90% in the primary tumor was 25%, contrasting with a disease-free survival of 54% in those patients with EGF-R levels <90% (P < 0.05).
Conclusions: There is a progressive increase in EGF-R expression from benign vulvar epithelium to primary malignant tissue to metastatic lesions within the same patient. Increased expression of EGF-R in the primary vulvar malignancy is significantly associated with lymph node metastasis and decreased patient survival. Increased expression of EGF-R in histologically benign vulvar epithelium has a significant association with lymph node metastasis and may predict decreased patient survival.