Bacillus Calmette-Guerin (BCG) is the main intravesical immunotherapy for early-stage bladder cancer. It can help the immune system get rid of cancer cells in the bladder but may cause side effects.

BCG is a liquid drug that doctors deposit directly into your bladder through a catheter. There, it prompts the immune system to target cancer cells. Doctors have been using this method of treating early-stage bladder cancer for 40 years.

It is made from a weakened strain of Mycobacterium bovis, a vaccine for tuberculosis.

Continue reading to learn more about BCG, how it’s used, and what you can expect from treatment.

Doctors typically recommend BCG to treat carcinoma in situ and non-muscle invasive bladder cancer.

This can include noninvasive (stage 0) and minimally invasive (stage 1) bladder cancers. It usually follows a procedure called transurethral resection of bladder tumor (TURBT) to help prevent recurrence.

As it only affects cells inside the bladder, it’s not useful for later-stage bladder cancer that has spread into or beyond the bladder lining, or to other tissues and organs.

BCG treatment is more effective than TURBT alone or TURBT with chemotherapy in preventing recurrence.

Before your first treatment session, a medical professional typically provides instructions for you to follow before and after the procedure. They may also ask for a full list of any medications you take, as some can interfere with BCG treatment. Your care team may have to stop using them temporarily or switch to alternatives during the course of your treatment.

Instructions for before you start a BCG treatment may include:

  • not taking certain medications, such as diuretics and antibiotics, that may interfere with your BCG treatment, as approved by your care team
  • limiting your fluid intake for 4 hours before the procedure
  • limiting your caffeine intake before the procedure
  • a recommendation to urinate just before the procedure so you can hold the medication in your bladder for several hours

A healthcare professional inserts a urinary catheter through your urethra and into your bladder. Sometimes, a healthcare professional may give you a local anesthetic to make the procedure more comfortable.

Then the BCG solution is injected into the catheter. The catheter is clamped off so the solution stays in your bladder. Some doctors may remove the catheter at this time.

You have to hold the solution in your bladder. A doctor may instruct to lie on your back and roll from side to side to make sure the solution reaches your entire bladder.

After about two hours, the catheter is unclamped so the fluid can be drained. If the catheter was already removed, you’ll be asked to empty your bladder at this time.

A doctor typically provides instructions to follow after treatment. This can help prevent the spread of BCG to others. You may need to:

  • Drink a lot of liquid to flush the medication from your bladder for 8-12 hours after treatment.
  • Urinate sitting down to prevent urine from splashing onto your skin for 6 hours after treatment.
  • Avoid using public restrooms for 6 hours after treatment.
  • For 6 hours after treatment, disinfect your urine and toilet each time after urinating by adding 2 cups of bleach into the toilet and closing the lid. Let it stand for about 20 minutes before flushing with the lid down.
  • For 6 hours after treatment, wash your genital area very carefully after you urinate, so your skin doesn’t become irritated from the BCG. Wash your hands thoroughly, too.
  • Avoid sex for 48 hours after treatment.
  • Use a condom or other barrier method between treatments and for 6 weeks following your final treatment.
  • Avoid getting pregnant or breastfeeding while on BCG therapy.

Treatment is usually given every week for 6 weeks. After that, some doctors may recommend additional treatment sessions, known as maintenance therapy for up to 3 years.

If the cancer comes back, a doctor may recommend additional BCG treatments.

One benefit of BCG is that while it affects the cells in your bladder, it doesn’t have a major effect on any other part of your body. But it can cause side effects that include:

Talk with a medical professional if symptoms last more than a few days.

White rare, BCG can potentially spread through the body and cause a serious infection. Symptoms of this can include:

  • a high fever that doesn’t respond to aspirin or other fever reducers
  • confusion
  • dizziness or lightheadedness
  • shortness of breath

Serious complications of infection can include:

  • inflammation of the lungs
  • hepatitis
  • inflammation of the prostate and testicles

If you have any sign of serious infection, seek immediate medical attention.

Cancer treatment usually involves more than one type of therapy, which can be given at the same time or one at a time. That makes it difficult to compare one treatment to another.

Some factors can determine your options for treatment. These can include:

  • type of bladder cancer
  • stage at diagnosis
  • your age and general health
  • how well you tolerate certain treatments
  • whether you have a weakened immune system

Doctors typically recommend BCG following TURBT in early-stage bladder cancer.

BCG treatment may result in fewer side effects than systemic chemotherapy, which affects your entire body. It may also reduce your chance of the cancer coming back or spreading.

Sometimes, TURBT isn’t an option, as would be the case in later-stage bladder cancer. Then it becomes necessary to remove part or all of the bladder. Chemotherapy or radiation therapy may also be recommended.

Each type of treatment has potential benefits and side effects to consider. A doctor can explain your options and help you decide on the best treatment for you.

BCG has been used to treat noninvasive bladder cancer for a long time. It’s an effective way to get your own immune system to attack the cancer cells in your bladder without harming other tissues and organs. It’s generally well-tolerated.

Based on records from 2013 to 2019, the five-year relative survival rates were 96-97% for stage 0 bladder cancer and 70-71% for stage 1 bladder cancer.

Survival rates

Health professionals often use 5-year survival rate as a measure of a disease’s outlook. It refers to the percentage of people with the disease that are still alive at least 5 years after their diagnosis.

5-year relative survival rate is another commonly used term. This is a measure of how many people with the disease are alive five years later compared to people without the disease.

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For many people, BCG therapy following TURBT surgery can reduce the risk of cancer returning or spreading within 5 years compared to TURBT alone or with chemotherapy.

Many factors can affect your individual outlook. These can include your:

  • age
  • cancer stage
  • general health
  • response to treatment

The following includes frequently asked questions about BCG treatment for bladder cancer.

Is BCG treatment chemotherapy?

BCG and chemotherapy are different types of treatments. BCG is an immunotherapy treatment for early-stage bladder cancer. But healthcare professionals can administer both treatments directly into your bladder (intravesically).

Is BCG better than chemo?

A 2022 review of studies suggests that people with stage 1 or 2 bladder cancer who receive BCG therapy after TURBT have lower rates of recurrence-free survival 5 years later than people who receive intravesical chemotherapy after TURBT, particularly among people at a higher risk. But the treatment that is best for you can depend on other factors, including your overall health.

Is BCG treatment painful?

BCG treatment typically isn’t painful but you may experience discomfort when the catheter is inserted and removed.

How many times can you have BCG treatments?

BCG therapy may have two phases that include an initial induction phase where you receive treatment weekly for 6 weeks and a maintenance phase, which may include additional treatments either weekly or less often. These treatments may continue up to 3 years, depending your risk for recurrence and other factors.

BCG is a type of immunotherapy for early-stage bladder cancer that hasn’t spread into the muscles of the bladder or other organs. Doctors typically recommend it following a TURBT surgery in order to reduce the risk of the cancer returning or spreading.

It can cause some side effects, including fever and urinary symptoms, that can last a few days. In some cases, it can cause more serious side effects, particularly in people with a weakened immune system.