Gynecologic Oncology Group randomized trials of combined technique therapy for vulvar cancer.

The Gynecologic Oncology Group (GOG) did a surgicopathologic study of vulvar cancer in which various prognostic factors in the primary lesion were evaluated and compared with the pathologic status of the lymph nodes in the groin dissections. In total, 558 patients were entered into this study (GOG Protocol 36) from November 1977 to February 1984. The 203 patients with positive groin nodes were eligible for a second study in which they were assigned randomly to receive either pelvic lymph node dissection or pelvic and groin irradiation (Protocol 37). One hundred fourteen patients were randomized to this study, and 53 of 59 patients in each treatment arm actually underwent the prescribed treatment. Acute and late toxicities were similar in both treatment arms. There was a significant difference in survival rate that favored the pelvic radiation treatment (P = 0.03). The largest difference in survival rates occurred in those patients with either of the poor prognostic findings (clinically suspicious fixed ulcerated nodes or two or more positive nodes). The 2-year survival rate was 68% for the radiation treatment arm and 54% for the surgical program. Pelvic radiation therapy has become the standard treatment for patients with positive groin nodes, especially if they are fixed or multiple. Based on these results, a subsequent study was designed to test whether radiation therapy could substitute for bilateral groin node dissection in patients with vulvar cancer (Protocol 88). Fifty-eight patients were enrolled in the study before entry was suspended on April 30, 1991, and the study was closed on November 1, 1991. In the first 49 evaluable patients, there were five groin recurrences in the irradiated patients, although there were no groin failures in the operated group. The radiation program used in this study may not have provided an adequate dose to the depth where the lymph nodes were located because the prescription called for dose calculations at a depth of 3 cm. Unless demonstrated in another study, groin irradiation cannot be used as an equivalent option to groin dissection. Aggressive preoperative chemoradiation treatment currently is being studied for patients with T3 lesions not amenable to standard radical vulvectomy. Surgical dissection of residual tumor plus bilateral groin dissections are to be done if the postradiation biopsy findings are positive. Patients with unresectable Stage T2 or T3 groin nodes are also eligible for this study (Protocol 101).