BCG treatment for bladder cancer typically spans up to three years when completed in full. It begins with a six-week induction phase and, for most patients, continues with periodic maintenance cycles over the following 36 months. The exact duration depends on your cancer’s risk level, how well you respond, and whether BCG supply is available.
The Induction Phase: First Six Weeks
Every BCG treatment plan starts with induction therapy: one treatment per week for six consecutive weeks. During each session, a nurse inserts a thin catheter into your bladder and delivers a liquid solution containing a weakened strain of bacteria. You then hold the solution in your bladder for about two hours before urinating it out. The entire clinic visit is relatively short, and you go home the same day.
After induction, your doctor will perform a cystoscopy (a camera exam of your bladder) to check whether the cancer has responded. This typically happens around the three-month mark. What they find determines whether you move into the longer maintenance phase or need a different approach.
Maintenance Therapy: Up to Three Years
If your bladder responds well to induction, the standard maintenance protocol adds treatment cycles at 3, 6, 12, 18, 24, 30, and 36 months after the initial course. Each cycle consists of once-weekly instillations for three weeks, so you’re looking at seven separate three-week rounds spread across three years.
Completing the full maintenance schedule matters significantly. Research shows that patients who received only the induction course had nearly four times the risk of tumor recurrence compared to those who continued with maintenance. Patients who completed 13 to 15 total instillations had the lowest recurrence rates of any group studied. In practical terms, finishing maintenance is one of the most important things you can do to keep the cancer from coming back.
Not everyone needs the full three years, though. For intermediate-risk tumors, some doctors limit maintenance to one year. High-risk tumors, including high-grade disease and carcinoma in situ, generally warrant the complete three-year course.
What Each Treatment Session Feels Like
The catheter insertion takes only a few minutes and causes brief discomfort similar to a urinary tract sensation. Once the solution is in your bladder, you’ll be asked to hold it for up to two hours. Some clinics ask you to lie down or shift positions during that time to help the solution contact all surfaces of the bladder lining. Others let you sit or move around normally. Practices vary, and researchers are still studying whether positioning makes a meaningful difference.
Most people experience irritative urinary symptoms afterward: frequent urination, burning, and urgency that can last one to three days. Some develop flu-like symptoms including low-grade fever, fatigue, and body aches. These side effects tend to be worst during the induction phase and generally lessen during maintenance. About 5% of patients develop side effects severe enough that they need to stop BCG entirely.
Why Your Timeline Might Be Shorter
BCG has been in a global supply shortage for several years, and that shortage directly affects how long treatment lasts. When supply is limited, the American Urological Association recommends prioritizing BCG for high-risk patients who need induction and, when possible, reducing maintenance to one year instead of three. Doses may also be split to one-half or one-third strength so that a single vial can treat multiple patients on the same day.
If BCG is completely unavailable, your doctor may substitute other medications delivered directly into the bladder. These alternatives follow their own schedules, typically involving an induction phase followed by monthly maintenance for up to a year. The specific drug and timeline will depend on what your treatment center has in stock and your cancer’s characteristics.
Beyond supply issues, some patients stop early because the cancer doesn’t respond to induction, because side effects become intolerable, or because a recurrence during maintenance signals that BCG alone isn’t working. In those situations, your urologist will discuss next steps, which could range from a different bladder-delivered therapy to surgery.
A Typical Treatment Timeline
- Weeks 1 through 6: Induction therapy, one instillation per week
- Month 3: First maintenance cycle (3 weekly instillations), plus cystoscopy to assess response
- Month 6: Second maintenance cycle
- Month 12: Third maintenance cycle
- Months 18, 24, 30, 36: Continued maintenance cycles every six months
Between cycles, you’ll have regular cystoscopies and urine tests, typically every three to six months. These monitoring visits continue even after BCG treatment ends, often for five years or longer, because bladder cancer has a relatively high rate of recurrence. The BCG treatments themselves involve roughly 27 instillations over three years if you complete the full course, but the total number of clinic visits will be higher once you factor in surveillance.