Objective: To observe the effects of intravesical instillation of immunotoxin (IT) on the prevention of recurrence of bladder carcinoma.
Methods: 128 patients with superficial bladder carcinoma or bladder carcinoma of T2 stage underwent operation, and then were randomly divided into 3 groups 2 - 3 weeks after operation to be instilled intravesically with solution of mitomycin (n = 53), Calmette-Guerin vaccine (n = 30), or IT (n = 45) once a week for 8 weeks and then once every month for 8 months respectively. Cystoscopy, blood routine examination, routine urine examination, and liver function test were conducted every 3 months. Immunohistochemistry was used to examine 30 samples of resected carcinoma. The effects and side effects were observed. Recurrence was verified by cystoscopy and/or ultrasonography, CT, and surgery.
Results: Out of the 30 samples of resected bladder carcinoma, 27 were staining positive (+ - + + +) with a positive rate of 90%. The binding activity was significantly different between the G(1) carcinoma of and the G(3) carcinoma (P < 0.05) and not significantly different between the G(1) and G(2) carcinomas and between the G(2) and G(3) carcinomas (both P > 0.05). The higher the grade of carcinoma, the stronger the binding activity of IT (P < 0.05). The recurrence rate in the first year were 11.1%, 10.0%, and 15.1% in the IT, BCG, and MMC groups respectively without significant difference between any 2 groups (all P > 0.05); and the recurrence rate in the 2nd year were 24.4%, 30.0%, and 28.3% in the 3 groups respectively without significant difference between any 2 groups (all P > 0.05). The side effect rate were 17.8% on the IT group, significantly lower than those in the other 2 groups (70.0% and 56.6% respectively, both P < 0.01). However, the side effect rates between the BCG group and MMC group was not significantly different (P > 0.05).
Conclusion: IT is more effective on the prevention of recurrence of carcinomas with higher malignancy and has fewer side effects. The short-term effect of IT is similar to those of BCG and MMC. The activity of IT is associated with the grade and not the stage of carcinoma.