ObjectiveThis study was performed to evaluate treatment outcomes and define prognostic factors for primary vaginal cancer treated with definitive radiotherapy.Materials and MethodsWe retrospectively analyzed 38 patients with primary vaginal cancer who received radiotherapy with curative intent between January 1981 and August 2008. Of these 38 patients, 6 were excluded from this analysis because of other uncontrolled malignancy (n = 1), uncommon histology (n = 4), or insufficient medical records (n = 1). Twenty-three patients (72%) presented with early-stage disease (International Federation of Gynecology and Obstetrics stages 0, I, or II). Eleven patients (34%) were treated with external beam radiotherapy (EBRT) alone and 21 patients (66%) with EBRT plus brachytherapy (BT). Low–dose rate cesium-137 was used with intracavitary technique for most of the patients who received BT. Five patients received chemotherapy. The median total dose in patients who received EBRT and EBRT+BT was 50.4 Gy (range, 39.6–70.4 Gy) and 78.9 Gy (range, 72.0–87.0 Gy), respectively.ResultsThe median duration of follow-up was 38 months. Five-year overall survival, cause-specific survival, disease-free survival, local control, and regional control rates for the analyzed patients were 75%, 88%, 58%, 62% and 90%, respectively. Thirteen patients had treatment failure as follows: local (n = 7), distant (n = 1), local plus regional (n = 1), local plus distant (n = 2), and local plus regional plus distant (n = 2). Primary tumor size was a significant prognostic factor for disease-free survival (P = 0.039).ConclusionsDefinitive radiotherapy is an effective treatment modality for primary vaginal cancer. Local failure was the major failure pattern, and achievement of local control is important for disease control and survival.