[Determination of potential doubling time using in vitro continuous labeling method with bromodeoxyuridine:...

Using in vitro continuous labeling with bromodeoxyuridine and immunohistochemical staining, potential doubling time (Tpot) was calculated in 24 patients with head and neck carcinoma treated with radiotherapy. There was no evident correlation between Tpot and tumor response in the cases treated with external irradiation. However, in one case of T2N0 mesopharyngeal carcinoma with short Tpot, tumor was microscopically residual even though it showed good radioresponsiveness during radiotherapeutic course. Meanwhile, all patients treated with brachytherapy showed complete response in spite of various Tpot. Tpot seems significant in the selection of fractionation to control head and neck carcinoma with external radiotherapy.