• Carcinoma in situ (CIS)
• Superficial invasive TCC
• Muscle Invasive TCC

CIS may affect the entire bladder mucosa. Therefore, the therapy directed to its eradication must treat the entire mucosal surface. Bacille Calmette-Guerin (BCG) is a weakened strain of Mycobacterium bovis-a cousin of the organism primarily responsible for tuberculosis. When instilled as a solution into the bladder-known as intravesical therapy-the body recognizes this foreign agent and a powerful immune response ensues. Known as "immunotherapy", the resulting reaction simultaneously destroys many if not all of the abnormal cells composing the CIS. This treatment is instilled through a catheter usually once a week for six weeks. At times, additional courses of 6 week treatments are necessary in the event of recurrent CIS. "Maintenance" treatment(once-a-month) may be given after each 6-week cycle of intensive/acute therapy to minimize risks of recurrence.

As with any treatment, potential side effects exist. The most common is bladder irritability, where individuals experience any possible array of symptoms including burning on urination, urinary frequency, urgency, and/or hematuria or bleeding in the urine. In rare cases, the bladder may become scarred or contracted after intravesical BCG treatment. Although uncommon, more systemic symptoms can occur, such as fevers, chills, or joint aches. If prolonged fever or shaking chills occurs after treatment, this may be a sign of systematic infection and prompt medical attention should be sought. Systemic anti-tubercular medication may be needed.