Intravesical interferon treatment of superficial bladder cancer

Superficial transitional cell carcinoma (TCC) of the bladder and carcinoma in situ (CIS) have a high recurrence rate and a variable incidence of progressive disease. Conventional intravesical agents used to treat these carcinomas have achieved only a variable degree of success, and have adverse side effects. Recently, intravesical interferon has been explored as a treatment for TCC and CIS. In a randomized, controlled trial, patients with CIS exhibited a significantly higher rate of complete response (CR) to high-dose (100 x 10(6) IU) than to low-dose (10 x 10(6) IU) interferon (45% vs 6%, respectively, p less than 0.0001). To date, 9/19 patients in the high-dose CR group have maintained a CR for at least six months. Five patients receiving high-dose therapy and 5 receiving low-dose therapy subsequently underwent cystectomy, but median time to surgery was 33.5 weeks for the high-dose group vs eighteen weeks for the low-dose group. Intravesical interferon was generally well tolerated. These results suggest that randomized clinical trials are warranted to assess the efficacy of intravesical interferon, as compared to BCG, for the treatment of CIS.