RAPID TUMOR-CELL PROLIFERATION AFTER INDUCTION CHEMOTHERAPY IN OROPHARYNGEAL CANCER

Tumor cell kinetics were studied in vivo in a series of 97 patients wi th oropharyngeal cancer. The duration of S phase (tS), the labeling in dex (LI), and the potential doubling time (Tpot) were obtained by flow cytometry measurements of a tumor biopsy obtained after intravenous i njection of 200 mg 5-bromodeoxyuridine to the patient. The mean LI was 9.7% (standard deviation [SD], 5.4), the mean tS was 10.1 hours (SD, 3.6), and the mean Tpot was 4.6 days (SD, 3.5). No significant relatio nship was found between the Tpot or LI and the size of the tumor, noda l status, histological grade, or the site of the primary within the or opharynx. Conversely, aneuploid tumors had longer tS (P<.001), higher LI (P<.001), and shorter Tpot (P<.05) than the diploid tumors. The mea n LI and Tpot of the tumors obtained after induction chemotherapy were significantly higher and shorter, respectively, than those measured b efore any treatment. The data strongly suggest that rapid tumor cell p roliferation frequently occurs in oropharyngeal cancer which had respo nded poorly to chemotherapy.