Prognostic value of histopathological response to radiotherapy and microvessel density in oral squamous cell carcinomas.

The prognostic value of histopathological response to preoperative radiotherapy (50 Gy) in radically resected oral carcinomas was studied in 39 consecutive patients. Microvessel density (MVD) was evaluated for relation to radioresponse and outcome. Resected tumour tissue was examined histopathologically and response to radiotherapy was scored according to induced morphological changes. Pretreatment biopsies were stained with antibodies to von Willebrand factor to evaluate MVD in hot-spot regions, in stromal tissue and in tumour epithelial tissue. Histopathological response to radiotherapy was highly prognostic of local failures and survival (p = 0.002), though microscopic surgical radicality was obtained. In good responders to preoperative radiotherapy, the 5-year survival rate was 68% compared with 24% in poor responders. In 12 patients with local recurrence after radical surgery, 11 had poor histopathological radiotherapy responses. In univariate analysis, a high MVD score in tumour epithelium was associated with poor clinical outcome but MVD did not correlate with histopathological radiotherapy response.