Potential role of microvessel density in predicting radiosensitivity of T-1 and T-2 stage laryngeal squamous cell carcinoma treated with radiotherapy

Curative radiotherapy is the first choice of therapy for T-1 and T-2 stage laryngeal squamous cell carcinoma (LSCC) patients to preserve their phonati on, Patients with recurrent tumors who undergo salvage surgery require prol onged nasal feeding. Therefore, clinical interest has been focused on eluci dating a predictive factor indicating which tumors are likely to be radiose nsitive before radiotherapy. We analyzed the relations between radiosensiti vity and clinicopathological factors (gender, tumor location, histological factors, and clinical tumor-node-metastasis stage), expression of apoptosis -related proteins (p53, bar, bcl-2), apoptotic index using the terminal deo xynucleotidyltransferase-mediated nick end labeling method, expression of c ell proliferation-related proteins (Ki-67-labeling index and epidermal grow th factor receptor overexpression) and microvessel density (MVD, vessels/fi eld = 0.391 mm(2)) in biopsy specimens from 31 LSCC patients given radiothe rapy (total radiotherapy dose of 52-70 Gy over 4-6.5 weeks). Univariate ana lysis revealed that tumors with a high MVD (greater than or equal to 35 ves sels/field) showed better radiosensitivity than those with a low MVD (<35 v essels/field, P = 0.008) and that a high Ki-67-labeling index (greater than or equal to 40%) was weakly associated with radiosensitivity (P = 0.056), Multivariate analysis and Kaplan-Meier analysis showed that MVD alone had s ignificant predictive power for radiosensitivity in T-1 and T-2 stage LSCCs after radiotherapy (P = 0.012, 0.0003, respectively). No significant assoc iation between clinicopathological factors, or of overexpression of p53, ba r, bcl-2, epidermal growth factor receptor, or apoptotic index, with radios ensitivity was found, These results indicate that MVD is a potentially usef ul clinical factor predicting radiosensitivity for patients with early stag e LSCCs before treatment.