Contribution of cell cycle and DNA content study by flow cytometry in the prognosis of superficial bladder cancer: Tunisian experience

Clinico-pathological study of superficial bladder cancer (pTa/pT1) informs about prognostic factors such as the size of the tumor, its uni or multifocal character, its grade and stage. Presently, these factors constitute the basis of therapeutic decision but do not allow to foresee the prognosis with certainty. Many technics have contributed to a better knowledge of such tumors; however, they have not allowed to fully master prognostic uncertainties. During the last decades, cell cycle and DNA content study by flow cytometry has been developping, bringing an additional prognostic element to various types of tumors. We have decided to study the impact of this technique to the assessment of the prognosis of superficial bladder tumors. The study concerned 65 patients presenting superficial bladder tumors (pTa/ pT1), with a follow-up of at least two years in case of not recurrence and in case of recurrence, having had a second resection with analysis of sections. Flow cytometry was applied to formol-fixed and paraffin-embedded endoscopic resection material of initial tumors by simple-labelling of DNA with propidium iodide. Following cytometric study, 35 (54%) of tumors were aneuploid and 30 (46 %) were diploid. For the diploid ones, S-phase mean value was 14.94% (from 2.72% to 33.43%); and G2M mean value was 8.3 (from 1% to 18%). The presence of an DNA- aneuploid peak had a predictive value of recurrence and progression in stage, with relative risks of 12 and 6.85 respectively. It was also correlated with the histological grade and stage. On the other hand, S-phase and G2M values had no prognostic significance.