Intravesical therapy for bladder cancer

Although transurethral resection of bladder tumor (TURBT) is effective therapy, up to 45% of patients will have a recurrence within 1 year after TURBT alone. Further, there is a 3 - 15% risk of tumor progression to muscle invasive and/or metastatic cancer. Depending on patient and tumor characteristics, a number of patients may benefit from some form of intravesical therapy. Adjuvant therapy is effective in avoiding post-TURBT implantation of tumor cells, eradicating residual disease, preventing tumor recurrence, and to delay or reduce tumor progression through direct cytoablation or immunostimulation.

The role of risk assessment in the management of nonmuscle invasive bladder cancer (NMIBC) and the indications for the use of intravesical agents are discussed. Findings from major randomized clinical trials on BCG, interferon and various chemotherapeutic agents are summarized; key aspects of drug pharmacology, drug efficacy, side effects, and toxicity are also covered.

The reader will gain a basic understanding of the role of risk assessment in determining the need for intravesical therapy, as well as an overview of the different types of agents in use in the United States today.

The type of intravesical therapy used is based on the risk groups as noted in the European prognostic tables. Bacillus Calmette-Guerin (BCG) is the most commonly used first-line agent immunotherapeutic agent for prophylaxis and treatment of carcinoma in situ and high-grade bladder cancer. Other immunotherapeutic options include the interferons, interleukins 2 and 12, and tumor necrosis factor, all of which have activity in BCG refractory patients, although with low durable remission rates. Studies have shown that chemotherapy prevents recurrence but not progression. The available data on intravesical chemotherapy do not indicate that any single agent currently in use is clearly better than any other. Therefore, the selection of a chemotherapeutic agent is usually based on cost, toxicity, and availability as well as on physician preference and experience.