Treatment for Bladder Cancer: Intravesical Options, Mitomycin C, BCG, Valrubicin, Apaziquone
Mitomycin C is a naturally derived chemotherapy that is isolated from the streptomyces bacteria. This drug is used for the treatment of various cancers, but in Urology it is used for the treatment of superficial bladder cancer, the most common type of bladder cancer that is diagnosed. Over 70,000 cases of bladder cancer are diagnosed in the United States yearly. Intravesical therapy is used to decrease the likelihood of tumor recurrence.
Mitomycin C is used intravesically (placed directly into the bladder) for the treatment of superficial bladder cancer. It is a liquid solution that is placed into the bladder through a catheter that is in place usually within 6 hours of the surgery. The catheter is then removed and the patient is asked to not urinate for approximately two hours, which gives the drug ample time to come into contact with all the surfaces of the bladder wall. The drug creates a crosslinkof the DNA that will ultimately lead to cell death.
This drug had been used more widespread than it is currently used as studies have shown that it was less effective in preventing tumor recurrence compared to BCG, another intravesical agent. Its main indication now is for cases of BCG failure. Over the last few years, there has been renewed interest in using this agent for disease that has not responded to other intravesical agents.
BCG (Bacille Calmette-Guerin) is presently the gold standard drug for the treatment of superficial bladder cancer. It is an attenuated tuberculosis virus that is placed intravesically. This substance is thought to be an immune modulator and works by creating a local immune response. It is most commonly used several weeks after the removal of the tumor for a series of six to eight treatments. Some patients will also undergo maintenance therapy for up to a year.
Valrubicin has recently become available for the treatment of BCG refractory cases of bladder cancer. Evidence exists that supports the use of this agent with its major side effects being bladder irritation.
The newest intravesical agent, apaziquone (Spectrum Pharmaceuticals), is presently in phase III clinical studies. Preliminary data has demonstrated this drugs efficacy in preventing recurrence of the disease and the FDA has granted Fast-Track status for its development. The drug is instilled into the bladder immediately after the resection of the bladder tumor. Side effects and toxicity have been reported as being minimal with the use of this agent.