Treatment for superficial bladder cancer
Risk factors are used to predict tumor aggressiveness and thereby provide logic on when to place medications into the bladder to treat the cancer (intravesical therapy).7 Patients with small, single low-grade tumor with a normal amount of DNA (diploid) that are limited to the urothelium (Ta) are at low risk for recurrence. In these patients, random bladder biopsies and the results of post resection cytologic examinations are usually normal. Generally, these patients are treated by transurethral resection followed by periodic cystoscopy, cytology and DNA ploidy evaluations. In these, intravesical therapy in addition to removal of the tumor through the cystoscopic instrument is generally administered only following tumor recurrence.
Patients with multiple tumors , high-grade, abnormal amounts of DNA ploidy (aneuploid), with carcinoma in situ or tumor penetration into the lamina propria are at high risk for tumor recurrence and progression. Usually, random bladder biopsy specimens and post resection cytologic examinations reveal abnormalities. High risk patients are candidates for intravesical therapy with bacillus Calmette-Guerin (BCG), mitomycin, doxorubicin or thiotepa. These agents are typically instilled into the bladder through a urethral catheter for two hours weekly for six to eight weeks. Occasionally, long-term maintenance treatment regimens are employed.
Clinical studies may have various endpoints such as tumor recurrence, tumor progression or patient survival. In clinical trials comparing transurethral resection plus and an intravesical agent versus transurethral resection alone, a significant reduction in tumor recurrences was noted in 4 of 5 BCG studies, 2 of 5 mitomycin studies, 2 of 4 doxorubicin studies, and 6 of 10 thiotepa studies; and a significant reduction in tumor progression was documented in 3 of 3 BCG studies, 0 of 2 mitomycin studies, 0 of 2 doxorubicin studies, and 0 of 3 thiotepa studies.8 Of these agents BCG is the only one shown to result in a survival advantage over transurethral resection alone. The above studies demonstrate why BCG is favored as the first-line intravesical agent. However, recent pharmacologic studies involving mitomycin suggest its efficacy can be substantially increased by completely draining the bladder prior to drug administration, minimizing urine production, alkalinization of urine, and increasing the drug concentration.9 Application of these types of pharmacologic principles may also improve the efficacy of doxorubicin and thiotepa.
To access any part of this article just click over the name of the section