[Biological behavior of untreated bladder carcinoma in situ]

The biological behaviour of initially untreated carcinoma in situ of the bladder was studied in 20 patients. A 35.4-month follow-up revealed a heterogeneous behaviour of this disease entity. Diffuse tumors were clearly distinct from focal tumors. The evolution of the former appeared to be more aggressive: no spontaneous remission was observed, 58.3% remained as such while 41.6% progressed to muscle layer infiltration. Focal tumors evolved more favourably: only 1 (12.5%) developed into diffuse carcinoma in situ, 2 (25%) continued to be positive for cytology, while 4 (50%) remitted spontaneously. We therefore consider that both patient groups must be treated upon diagnosis. Intravesical treatment, which achieves a high rate of complete response, is advocated.