Pre-treatment 3H-TdR labelling of cervical biopsies: histology, staging and tumour response to radiotherapy.

Pre-treatment data from tumour biopsies labelled in vitro with tritiated thymidine are reported for 54 patients undergoing radical radiotherapy by 137Cs or Cathetron 60Co intracavitary insertions plus external irradiation for carcinoma of the uterine cervix. Labelling indices were obtained ranging from 1.8 to 27.8%. No correlation was observed between mean labelling indices and the histological type of tumour or its degree of differentiation. Comparison of data obtained in this study with previously reported data for carcinoma in situ and invasive carcinoma indicate that with increasing clinical stage of the disease, a considerable lengthening of the potential doubling time of the tumour cells, from less than 1 to 8 days, occurs. The degree of vaginal spread of the tumour was directly related to the degree of parametrial involvement. The mean time taken for the vaginal component of the tumour to resolve following radiotherapy was related to its initial spread and the pre-treatment labelling index. The greater the spread of the tumour, the lower the labelling index and the longer the time taken for resolution. Up to 1 year following radiotherapy the incidence of locally recurrent, or metastatic disease was unrelated to the pre-treatment labelling index.