The topical use of misonidazole in bladder cancer.

Penetration studies of MIS after intravesical administration showed adequate concentrations with a gradient across the tumor. After instillation of 2.5 g in 50 ml water the concentration in the deep parts of the tumor amounted to about 100 microgram per ml. This corresponds to a SER for hypoxic cell of the order of 1.7. A more uniform tissue distribution of the drug was noted 3.5 hours after an oral dose of 3 g/meter square. The concentration in the deep parts of the tumor and perivesical tissue was of the order of 100 micrograms/g. The concentration in these regions are relevant to preoperative irradiation which aims at sterilizing the deep infiltrating margins. The intravesical use with or without oral augmentation is suitable for use in association with concentrated preoperative radiotherapy regimens. The topical use of MIS in such regimens markedly reduces the risk of neurotoxicity. The tissue concentration resulting from the two routes proved to be additive. The higher concentration in lymph nodes after the oral route the greater concentration and prolonged contact after combined administration may have therapeutic merits.