Chemoimmunoprophylaxis of an experimental bladder cancer with retinoids and Bacillus Calmette Guérin

The prophylactic effect of 2 retinoids (Ro 4-3780 and Ro 10-9359), either alone or in combination with Bacillus Calmette Guérin (BCG), was studied in an experimental murine bladder tumor model. The incidence of tumor takes in all treatment groups was lower than in the control group. Both BCG and Ro 10-9359 were effective in decreasing the percentage of tumor takes and the simultaneous use of these agents was more effective than either one alone. Ro 10-9359 was found to possess more antitumor activity than Ro 4-3780 in this tumor model. Treatment of mice with a combination of Ro 10-9359 and BCG resulted in an 83.3 per cent incidence of complete tumor regression within 80 days. Results suggest that vitamin A derivatives may be useful in the prevention and treatment of bladder cancer and that the activity is likely potentiated by nonspecific stimulation.