TUMOR-GROWTH RATES IN SQUAMOUS CARCINOMA OF THE HEAD AND NECK MEASURED BY INVIVO BROMODEOXYURIDINE INCORPORATION AND FLOW-CYTOMETRY

The cell kinetics of 82 squamous cell carcinomas of the head and neck were studied by in vivo administration of the thymidine analogue, bromodeoxyuridine (BrdUrd) Ploidy, BrdUrd labelling index (LI), duration of S-phase (Ts), potential doubling time (Tpot) and S-phase fraction (SPF) were measured by flow cytometry on 50-mu-m paraffin embedded sections. The range of values obtained compared well with other in vivo cell kinetic studies of head and neck cancer. Aneuploid tumours had a significantly higher BrdUrd labelling index and SPF, and a short Tpot than diploid tumours To validate the use of 50-mu-m sections for measuring cell kinetic parameters by flow cytometry a comparison of values obtained by 50-mu-m sections and small blocks of tissue was made. No significant difference was found between the two methods. Reproducibility of values between two consecutive thick sections was also good. We conclude that reproducible cell kinetic measurements can be made in tumour samples using 50-mu-m sections of BrdUrd labelled tissue.