Thiotepa effects on urinary cytology in the interpretation of transitional cell cancer

In recent years we have witnessed increased reliance on 2 modalities in the management of patients with superficial transitional cell cancer of the bladder, that is intravesical chemotherapy for the control of existing and recurrent disease, and urinary cytology for the diagnosis of persistent or new neoplastic cells. This development has prompted some concern as to whether the use of chemotherapy might affect the morphological appearance of cells so as to make the interpretation of cytological specimens in this setting unreliable. We describe morphological differences between neoplastic cells and normal as well as cancer cells exposed in situ and in vitro to thiotepa. An appreciation of these differences has permitted accurate diagnosis of urinary cells in the presence or absence of cancer despite the regular use of this agent. Thus, it appears that the status of bladder cancer can be monitored successfully by an assessment of urinary cytology in the context of long-term treatment and prophylaxis with this agent.