Primary squamous cell carcinoma of the vagina: prognostic factors, treatment patterns, and outcomes

Primary squamous cell carcinoma (SCCA) of the vagina is a rare malignancy with limited data to guide treatment. We evaluated prognostic factors and outcomes for patients with primary vaginal SCCA treated with definitive radiation therapy at a single institution.

A retrospective analysis was performed on patients treated for primary vaginal SCCA from 1959 to 2011.

Ninety-one patients with primary vaginal SCCA were treated with definitive radiation therapy. Thirty-eight patients had FIGO stage I, 28 stage II, 13 stage III, and 12 stage IV disease. The mean total dose was 70.1 Gy. Two-year overall survival (OS), locoregional control rate (LRC), and distant metastasis-free survival by stage were, respectively: stage I: 96.2%, 80.6%, 87.5%; stage II: 92.3%, 64.7%, 84.6%; stage III: 66.6%, 44.4%, 50.0%; and stage IV: 25.0%, 14.3%, 25.0%. Treatment with total dose over 70 Gy was associated with improved OS (p=0.0956) and LRC (p=0.055). There was a significant difference in median dose received by patients who developed grade 3/4 toxicity compared to those who did not (82.9 Gy versus 70.0 Gy, p=0.0019). None of the 10 patients treated with IMRT experienced locoregional recurrence or grade 3/4 toxicity. Tumor size larger than 4 cm was associated with worse OS (p=0.0034) and LRC (p=0.006).

Our analysis suggests that the optimal dose for definitive treatment of SCCA of the vagina lies between 70 and 80 Gy. Treatment with IMRT may allow for dose escalation with reduced toxicity and excellent LRC. Tumor size over 4 cm is associated with inferior outcomes and may require additional treatment modalities.