What Is the Standard Maintenance BCG Schedule?

After the first six weekly treatments, most people with higher-risk bladder cancer go on to maintenance BCG, a series of short treatment rounds spread over the following years. The standard version, called the SWOG or 6+3 schedule, adds a round of three weekly treatments at 3 and 6 months and then every 6 months, usually for up to 3 years in high-risk disease. People at intermediate risk often stop after about 1 year. Doctors regularly adjust the schedule for side effects and BCG supply, and few people complete every planned dose.

The Standard 3-Week Maintenance Schedule, Round by Round

The first course, called induction, is one BCG treatment a week for six weeks, usually starting a few weeks after surgery to remove the tumor.¹ Maintenance means the further BCG rounds given after induction to keep the cancer from returning.² The most widely used maintenance plan is called the SWOG or 6+3 schedule, after the research group that tested it.³

Seven rounds of three treatments add up to 21 maintenance treatments over 3 years.¹¹ Counting induction, the full program comes to 27 bladder treatments.

Month counts usually start from the beginning of induction, so confirm this with your clinic. Ask the clinic for the round dates in writing so you can plan work and travel around them.

Maintenance does not mean the cancer is back; it is planned in advance. Skipping a round changes the schedule, so tell the team early about any conflict.

The gaps are three months at first and then six, so treatment is front-loaded when the risk of recurrence is highest and tapers afterward. Long treatment-free stretches are part of the design, not a sign that anything has gone wrong.

One Year or Three Years Depends on Your Risk Level

In a large European trial of about 1,350 people, intermediate-risk patients on full-dose BCG did no better with 3 years of maintenance than with 1.¹² For high-risk patients, 3 years lowered the chance of the cancer coming back, but only when full-strength doses were used.¹³ One year at one-third dose did worse than 3 years at full dose.¹⁴ Neither longer nor stronger treatment changed the chance of the cancer growing deeper or how long people lived.¹⁵ Some specialists use longer and lower-dose plans, with one-third doses given out to as long as 12 years.¹⁶

Doctors sort non-muscle-invasive bladder cancer into low, intermediate and high risk using tumor grade, stage, size, number of tumors and whether it has come back before. High grade, stage T1, or carcinoma in situ (flat, fast-growing cancer cells on the lining) generally points to the high-risk group. Intermediate risk often describes low-grade tumors that are multiple, large or recurrent. Your risk group shapes both the length of maintenance and whether BCG is advised at all, so it is worth finding it on your pathology report or asking your urologist which group you are in and which plan they are following.

Why Maintenance Is Worth the Extra Visits

Compared with induction alone, maintenance lowered the chance of the cancer returning by about 21%.¹⁷ A 21% reduction is relative: it lowers your existing chance of recurrence by about a fifth rather than removing it. It also lowered the chance of the cancer growing into a more dangerous stage.¹⁸ Many of the trials behind these figures were of limited quality, so the exact size of the benefit is uncertain.¹⁹ In high-risk disease, BCG treatment roughly halved the chance of progression over the long term.²⁰

A recurrence is a new tumor in the bladder lining, and it is often treatable again. Progression means the cancer has grown into the bladder muscle and may need bladder removal, which is why preventing it matters most.

BCG is a weakened tuberculosis germ that trains the immune system to attack cancer cells.²¹ It leaves immune cells primed to respond more strongly the next time they meet BCG, which is why repeat rounds help.²²

Side Effects and When Schedules Get Adjusted

Burning, urgency and slightly pink urine for a day or two after a treatment are expected, and they show the bladder lining reacting to BCG. A fever above 38.5°C (101.3°F), shaking chills, or any effect lasting beyond about 48 hours should prompt a same-day call to the clinic. BCG is live bacteria, so a fever that persists can signal an infection that needs treatment rather than waiting it out. Report every side effect before each new treatment so the team can adjust.

Effects often grow stronger with each round as the immune response builds. Tell the team early so they can delay a treatment or lower the dose before you feel you have to quit.

In the large European trial, a one-third dose caused no fewer side effects than the full dose.²⁸ Even so, some specialists lower the dose step by step when side effects build up.²⁹ About 8% of people stopped BCG because of side effects.³⁰

Few people finish everything on paper. In one large hospital group, only 10% of people who began the standard 3-week schedule finished all 21 treatments.³¹ In another hospital, 6% completed the full schedule.³² Talk with your team before quitting rather than stopping on your own.

What Happens During a BCG Shortage

During shortages, US urology groups give new high-risk patients’ induction priority over maintenance.³³ When supply is limited, maintenance should use one-third doses and stop at 1 year.³⁴ In a severe shortage, maintenance may not be given at all.³⁵ Intermediate-risk patients are usually switched to chemotherapy placed in the bladder instead of BCG.³⁶

New high-risk patients come first because they gain the most from a first course, which means people already in maintenance are the most likely to see their plan trimmed. This is a temporary measure to stretch supply, not a judgment that you need less treatment.

There are alternatives. Maintenance with gemcitabine and docetaxel after BCG induction kept cancer from returning about as well as BCG maintenance, and it was easier on patients.³⁷ Shortages can also mean fewer doses or a different BCG strain.³⁸

If your supply is cut, ask whether your plan has changed and why, and whether a chemotherapy drug will replace BCG for maintenance. It is also fair to ask whether you can make up missed doses once supply returns.

What a Maintenance Treatment Day Looks Like

Limit fluids for several hours beforehand so your urine doesn’t dilute the drug, and empty your bladder just before treatment.³⁹ If you feel unwell, check your temperature at home and call before coming in if you have a fever, since treatment is not given during an infection. Staff check your temperature and test your urine for blood or infection.⁴⁰

A nurse or doctor then passes a thin tube called a catheter into the bladder, and it carries the BCG in.⁴¹ You hold the BCG for 1 to 2 hours, then urinate.⁴² Some clinics ask you to change position so the drug reaches the whole bladder lining. Holding gets easier as the visits go on, and if you can’t hold it, urinate early and tell the staff. If the urine is very bloody, the treatment is usually postponed by a week.⁴³

Because BCG is live bacteria, urine needs careful handling afterward.⁴⁴ Sit to urinate, avoid public toilets, and add 2 cups of bleach to the toilet, then wait 15 to 20 minutes before flushing.⁴⁵ Some clinics ask you to do this for every trip to the toilet for the next 24 hours.⁴⁶ Avoid sex for 48 hours and use condoms throughout the treatment course.⁴⁷

Plan to spend about 2 to 3 hours at or near the clinic, counting check-in, the catheter and the holding time. At home, have a private toilet and bleach ready. Wash your hands and genitals after every trip to the toilet, and wash any clothes soaked by leaking urine separately in hot water.

Check-Ups and What If Cancer Returns

Cystoscopy, a camera check of the bladder through the urethra, plus a urine test, is done every 3 to 6 months for the first 2 years.⁴⁸ After that, check-ups are spaced farther apart.⁴⁹ A thin camera looks at the whole bladder lining, usually while you are awake after numbing gel, and the urine sample is checked for cancer cells at the same time. Any suspicious spot may be sampled or removed in a separate procedure.

Check-ups often fall close to maintenance round dates, so one visit may combine both. A clear result usually means the next round goes ahead as planned, while a suspicious finding may pause BCG while a biopsy is done.

If cancer returns, the timing matters. High-grade cancer that returns within 6 months of adequate BCG is counted as not responding to BCG.⁵⁰ Cancer that returns more than 2 years after the last dose may be treated much like cancer that has not had BCG.⁵¹ An early recurrence suggests more BCG is unlikely to work, while a late one may respond to restarting it. Bladder removal may come up if high-risk cancer keeps returning.

Some people whose cancer returns can still be treated through the bladder, with more BCG or chemotherapy.⁵² Docetaxel placed in the bladder cleared the cancer in up to 77% of people after BCG had failed.⁵³ Drugs that boost the immune system, given alongside BCG maintenance, are being tested.⁵⁴