DNA ploidy and the prognosis of stage pT1 bladder cancer.

The histopathological grade, proportion of "S"-phase nuclei and DNA ploidy values were linked and of prognostic significance in a retrospective series of stage pT1 bladder cancers. Nuclei were extracted from paraffin sections of 75 biopsies (56 patients). DNA ploidy and the proportion of "S"-phase nuclei were measured using flow cytometry. Progressive disease (pT2 or greater) developed within 3 years in 35% (6/17) of patients with poorly differentiated tumours, 35% (8/23) with aneuploid tumours and 35% (7/20) of those with a high proportion of "S"-phase nuclei. Of 8 tumours with all 3 features, progressive disease developed in 6 cases (75%). Of 9 patients who developed progressive disease, 8 (89%) had aneuploid tumours. Progressive disease did not develop in 11 patients with well differentiated tumours, compared with 4% (1/24) in diploid/tetraploid tumours and 7% (2/27) in those with a low/medium percentage of "S"-phase nuclei. In contrast to muscle-invasive disease, recurrent superficial tumours developed with a high incidence in all groups. Only 6/56 patients (11%) remained alive and disease-free for 3 years. It is concluded that these 3 features are of similar prognostic significance and accuracy in identifying patients requiring more aggressive therapy.