Factors affecting long-term outcome of irradiation in carcinoma of the vagina

Objective: This report evaluates prognostic and technical factors affecting outcome of patients with primary carcinoma of the vagina treated with definitive radiation therapy. Methods and Materials: A retrospective analysis was performed on records of 212 patients with histologically confirmed carcinoma of the vagina treated with irradiation. Results: Tumor stage was the most significant prognostic factor; actuarial 10-year disease- free survival was 94% for Stage 0 (20 patients), 80% for Stage I (59 patients), 55% for Stage IIA (63 patients), 35% for Stage IIB (34 patients), 38% for Stage III (20 patients), and 0% for Stage IV (15 patients). All in situ lesions except one were controlled with intracavitary therapy. Of the patients with Stage I disease, 86% showed no evidence of vaginal or pelvic recurrence; most of them received interstitial or intracavitary therapy or both, and the addition of external-beam irradiation did not significantly increase survival or tumor control. In Stage IIA (paravaginal extension) and IIB (parametrial involvement) 66% and 56% of the tumors, respectively, were controlled with a combination of brachytherapy and external-beam irradiation; 13 of 20 (65%) Stage III tumors were controlled in the pelvis. Four patients with Stage IV disease (27%) had no recurrence in the pelvis. The total incidence of distant metastases was 13% in Stage I, 30% in Stage IIA, 52% in Stage IIB, 50% in Stage III, and 47% in Stage IV. The dose of irradiation delivered to the primary tumor or the parametrial extension was of relative importance in achieving successful results. In patients with Stage I disease, brachytherapy alone achieved the same local tumor control (80-100%) as in patients receiving external pelvic irradiation (78-100%) as well. In Stage II and III there was a trend toward better tumor control (57-80%) with combined external irradiation and brachytherapy than with the latter alone (33-50%) (p = 0.42). The incidence of grade 2-3 complications (12%) correlated with the stage of the tumor and type of treatment given. Conclusion: Radiation therapy is an effective treatment for patients with vaginal carcinoma, particularly Stage I. More effective irradiation techniques, including optimization of dose distribution combining external irradiation and interstitial brachytherapy in tumors beyond Stage I, are necessary to enhance locoregional tumor control. The high incidence of distant metastases emphasizes the need for earlier diagnosis and effective systemic cytotoxic agents to improve survival in these patients.