Carcinoma in situ (CIS) of the urinary bladder consists in an early stage of bladder cancer, when the tumor(s) have affected only the innermost layers of the bladder wall. Left untreated, the carcinoma can affect deeper and deeper layers until it penetrates the wall and affects surrounding organs. The species of bacteria (NAME) (BCG) causes tuberculosis, but when attenuated for treating bladder CIS, the live bacteria cannot multiply and cause the disease. The bacteria cause an immune response that rids the bladder of the CIS tumors.
Bladder CIS
According to eMedicine, bladder CIS, a form of transitional cell carcinoma (TCC), affects 4,000 to 5,000 people in the United States each year, with men outnumbering women 3:1. It accounts for 10 percent of TCC, the rest being more invasive. CIS forms on the lining of the bladder wall and tends to spread flat along the inside of the bladder. If left untreated it can become invasive and affect deeper layers of the bladder. Symptoms include irritation when urinating and blood in the urine, but these symptoms occur also with urinary tract infection. With cystoscopy, which uses an instrument to see into the bladder, CIS appears red with a velvety texture. Experts believe smoking and exposures to environmental carcinogens causes most bladder cancers.
Instillation of BCG
The most common preparations of BCG, Tice and TheraCys, have similar compositions. Technically considered vaccines, they contain live and dead bacteria in a freeze-dried powder. Meyer et al., in their review article in "Postgraduate Medicine," explains that the physician activates the bacteria in 30 to 50 mL of saline (about an ounce) and then, using a catheter through the urethra, instills the solution into the bladder. Given the similarity of CIS symptoms to urinary tract infections, the physician must rule out such infections before instilling the BCG solution.
Retention in the Bladder
Meyer et al. go on to explain that the patient retains the solution for at least one hour and then passes it. During that hour, the patient lies on the back, the front and both sides for 15 minutes each, to ensure that the solution comes into contact with all of the bladder lining. While in the bladder, the BCG causes inflammation as the body's immune system fights against it. Immune system T-cells and macrophages rush to the site and attack the tumors along with the BCG bacteria. BCG also appears to interfere directly with the tumor growth.
Frequency and Number of Treatments
The patient will undergo weekly treatments for six weeks, after which the physician will perform a cytoscopy. If necessary, the patient will undergo another six-week regimen. Meyer et al. refer to various efficacy studies to note that CIS responds completely to the treatment in approximately 85 percent of patients, with some studies following patients for up 44 months. Patients receiving one or two treatments have a low rate of CIS recurrence.
Side Effects and Risks
Most patients experience side effects, according to Meyer et al. In addition to the risks of the catheterization, about 80 percent of patients experience irritation and difficulty urinating, 40 percent blood in the urine and 30 percent a fever from BCG. Meyer et al. recommend analgesics to alleviate the symptoms, which normally resolve within two days. Other rare but more serious effects may occur, including granulomas, allergic reactions and a severe systemic reaction to BCG. Brosman recommends that patients clean the toilet after urinating for the next three urinations to avoid exposing family members to the bacteria.
Alternative Treatments
Brosman lists several other chemotherapeutic agents that may be used instead of BCG, including mitomycin-C, gemcitabine and doxyrubicin, but BCG remains the treatment standard. Surgery does not constitute a feasible treatment because CIS often has small tumors dispersed inside the bladder, making it difficult the tumors and remove them all. Grossman et al. note that adding interferon to BCG can improve response rates and, for CIS that does not respond to BCG treatment, physicians may try valrubicin. Valrubicin, however, has a low response rate in treating these patients. Removal of the bladder may be necessary when chemotherapeutic agents fail.
Tags: affect deeper, bladder wall, blood urine, chemotherapeutic agents, deeper layers, inside bladder, into bladder