Purpose: To examine the prognostic value of three endogenous hypoxia markers (hypoxia inducible factor 1 alpha subunit [HIF1 alpha], carbonic anhydrase IX [CA-IX], and glucose transporter type 1 [GLUT-1]) on the clinical outcome in patients with early-stage glottic carcinoma primarily treated with radiotherapy (RT) and to determine the predictive hypoxic profile to choose the optimal treatment of early-stage laryngeal carcinoma.
Methods and materials: Immunohistochemistry for HIF1 alpha, CA-IX, and GLUT-1 was performed on formalin-fixed, paraffin-embedded, pretreatment tissue samples of 91 glottic squamous cell carcinoma specimens. The patient group consisted only of those with early-stage (T1-T2) glottic carcinoma, and all patients were treated with RT only. Relative tumor staining was scored on the tissue samples. Receiver operating curve analysis was performed to determine the optimal cutoff value for each tumor marker. Cox regression analyses for the variables HIF1 alpha, CA-IX, GLUT-1, gender, age, hemoglobin level, T category, N category, tobacco use, and alcohol use were performed with local control and overall survival as endpoints.
Results: HIF1 alpha overexpression in early-stage glottic carcinoma correlated significantly with worse local control (hazard ratio [HR], 3.05; p = 0.021) and overall survival (HR, 2.92; p = 0.016). CA-IX overexpression correlated significantly with worse local control (HR, 2.93; p = 0.020). GLUT-1 overexpression did not show any correlation with the clinical outcome parameters. Tumors with a nonhypoxic profile (defined as low HIF1 alpha and low CA-IX expression) had significantly better local control (HR, 6.32; p = 0.013).
Conclusion: The results of our study have shown that early-stage glottic laryngeal carcinomas with low HIF1 alpha and CA-IX expression are highly curable with RT. For this group, RT is a good treatment option. For tumors with HIF1 alpha or CA-IX overexpression, hypoxic modification before RT or primary surgical treatment should be considered.