Tumour cords in 52 human bronchial and cervical squamous cell carcinomas: inferences for their cellular kinetics and radiobiology.

Tumour cords have been measured in 33 cases of squamous cell carcinoma (SCC) of the bronchus and 19 cases of SCC of the uterine cervix. The overall mean cord radius for SCC in both sites was 104 microns, similar to the overall mean for various tumours in rodents. For tumour cells adjacent to blood vessels in cords of SCC, the mean Mitotic Index was 2.1% and from this value a rapid potential doubling time could be inferred (approximately 31 to 66 h). The proportion of dead cells within cords of cervical SCC was higher than in animal tumours. Using measured values for cord radius and published equations that describe the diffusion and consumption of oxygen in metabolising tissue, an attempt was made to calculate the oxygen partial pressure in vessels of cords of these SCC.