BCG Treatment for Bladder Cancer: What Happens, Side Effects and Warning Signs

Quick answer

BCG is an immune-based treatment delivered into the bladder after TURBT for some non-muscle-invasive bladder cancers. It is not intravenous chemotherapy. It aims to reduce recurrence and, in suitable patient groups, progression risk; it cannot guarantee that a tumour will never return.

Does everyone need BCG?

No. Low-risk tumours are not treated in the same way as CIS or high-risk disease. The decision considers pathology, risk group, previous treatment and general health. Bladder removal may also be discussed in very-high-risk disease or when high-grade disease persists despite appropriate BCG. BCG should not replace standard treatments for muscle-invasive cancer.

How is it given, and how many sessions are needed?

The medicine enters the bladder through a thin catheter placed through the urethra. The unit explains how long to retain it and the toilet and hygiene instructions afterwards. An initial course often consists of six weekly treatments. Suitable patients may continue with intermittent maintenance; total duration depends on risk and tolerance. The number of sessions alone does not establish whether treatment suits an individual.

Maintenance dose and duration have been investigated separately. For example, the EORTC trial compared one-year and three-year maintenance in intermediate- and high-risk patients. A study schedule should not be copied unchanged for every patient.

References for this section: University College London Hospitals NHS Foundation Trust. BCG treatment for bladder cancer. Oddens J, Brausi M, Sylvester R, et al. Final results of an EORTC-GU cancers group randomized study of maintenance bacillus Calmette-Guérin in intermediate- and high-risk Ta, T1 papillary carcinoma of the urinary bladder: one-third dose versus full dose and 1 year versus 3 years of maintenance. Eur Urol. 2013;63(3):462-72.

Why distinguish the first six instillations from maintenance?

Induction is the initial course; maintenance consists of further instillations at intervals when response and tolerance allow. The SWOG trial by Lamm and colleagues studied maintenance in selected Ta/T1 and CIS patients. Completing the first six instillations therefore does not always complete the entire plan. Equally, maintenance is not an unquestioned repetition of the first prescription: surveillance findings and adverse effects are reassessed.

In the trial by Oddens and colleagues, longer treatment did not have identical effects in intermediate- and high-risk groups. Reducing recurrence in high-risk disease is also a different outcome from proving a reduction in progression or death. Ask about the expected benefit and burden of additional instillations for your risk group, rather than assuming the longest course is always best.

References for this section: Lamm DL, Blumenstein BA, Crissman JD, et al. Maintenance bacillus Calmette-Guerin immunotherapy for recurrent TA, T1 and carcinoma in situ transitional cell carcinoma of the bladder: a randomized Southwest Oncology Group Study. J Urol. 2000;163(4):1124-9. Oddens J, Brausi M, Sylvester R, et al. Final results of an EORTC-GU cancers group randomized study of maintenance bacillus Calmette-Guérin in intermediate- and high-risk Ta, T1 papillary carcinoma of the urinary bladder: one-third dose versus full dose and 1 year versus 3 years of maintenance. Eur Urol. 2013;63(3):462-72.

Are fewer sessions, a lower dose and postponement equivalent?

No. Dose, number of instillations and the interval between them are separate variables. In the randomised NIMBUS trial, the group assigned fewer standard-dose instillations had more recurrences, and recruitment stopped. This does not mean that a single session postponed under medical supervision because of an adverse effect has the same consequence. It also does not establish that spacing out treatment yourself is safe.

In the trial by Brausi and colleagues, reducing dose or duration did not reduce adverse effects as expected across all groups. Record symptom severity, onset and duration. Individual assessment is needed rather than assuming either that a lower dose is always safer or that treatment must continue regardless of adverse effects.

References for this section: Grimm MO, van der Heijden AG, Colombel M, et al. Treatment of High-grade Non-muscle-invasive Bladder Carcinoma by Standard Number and Dose of BCG Instillations Versus Reduced Number and Standard Dose of BCG Instillations: Results of the European Association of Urology Research Foundation Randomised Phase III Clinical Trial "NIMBUS". Eur Urol. 2020;78(5):690-698. Brausi M, Oddens J, Sylvester R, et al. Side effects of Bacillus Calmette-Guérin (BCG) in the treatment of intermediate- and high-risk Ta, T1 papillary carcinoma of the bladder: results of the EORTC genito-urinary cancers group randomised phase 3 study comparing one-third dose with full dose and 1 year with 3 years of maintenance BCG. Eur Urol. 2014;65(1):69-76.

When might a session be postponed?

BCG should not be given during the first two weeks after TURBT, with visible bleeding, after traumatic catheterisation or during a symptomatic urinary infection. Tell the team beforehand about fever, new urinary symptoms, antibiotics or immunosuppressive medicines. Not every positive urine test means the same thing: a clinician distinguishes asymptomatic bacteriuria from active infection.

References for this section: EAU. Non-muscle-invasive Bladder Cancer: Disease Management.

Can burning and frequent urination occur?

Bladder irritation, burning, urgency and frequent urination can follow treatment. Some people have brief malaise or flu-like symptoms. If symptoms persist, worsen or substantially affect daily life, tell the team before the next session. Burning alone does not show either tumour progression or that treatment is definitely working.

Which symptoms need urgent assessment?

After BCG, a temperature of 38°C or higher, severe chills, shortness of breath, inability to pass urine or a marked deterioration in general condition requires immediate contact with your treatment team. If they cannot be reached, seek emergency care. Heavy bleeding or clots should also not be delayed. Tell the assessing team that you received intravesical BCG and when the last dose was given. Rare but serious BCG-related infections can occur; do not wait to reach a time threshold found online.

References for this section: Cancer Institute NSW, eviQ. Patient information — Bladder cancer: Intravesical BCG.

What information helps the team assess an adverse effect?

Note the date of the last instillation, highest measured temperature, symptom onset, ability to pass urine and medicines taken. Before every session, explain how the previous one went. Persistent burning may reflect treatment irritation, infection or another problem; its cause cannot be established from urine colour or a message alone.

With fever, severe chills or marked deterioration, do not wait for the next appointment. Tell the assessing team that BCG contains live attenuated bacteria and can rarely cause serious infection. Starting antibiotics or anti-tuberculosis medicines yourself may delay assessment; the clinician decides which investigations and treatment are needed.

References for this section: Cancer Institute NSW, eviQ. Patient information — Bladder cancer: Intravesical BCG. Brausi M, Oddens J, Sylvester R, et al. Side effects of Bacillus Calmette-Guérin (BCG) in the treatment of intermediate- and high-risk Ta, T1 papillary carcinoma of the bladder: results of the EORTC genito-urinary cancers group randomised phase 3 study comparing one-third dose with full dose and 1 year with 3 years of maintenance BCG. Eur Urol. 2014;65(1):69-76.

What should I do at home?

Ask for written unit instructions about fluids, toilet cleaning, sexual activity and medicines. The same fluid intake is not suitable for everyone with heart or kidney disease. Do not start antibiotics yourself, change the BCG dose or mix cleaning chemicals. The team will adjust the plan if a session is postponed or side effects develop.

Does cystoscopy follow-up stop when BCG finishes?

No. Response and follow-up are not determined only by symptoms improving. Cystoscopy and, when indicated, cytology or imaging continue according to risk. If a tumour recurs, its grade, stage and timing in relation to BCG are assessed. Not every recurrence is BCG-unresponsive disease; that term requires information about treatment received and timing.

References for this section: EAU. Non-muscle-invasive Bladder Cancer: Follow-up of Patients with NMIBC.

How do BCG intolerance, recurrence and unresponsive disease differ?

Intolerance means adverse effects prevent treatment from continuing. Recurrence means previously treated disease is detected again. BCG-unresponsive disease has a narrower definition involving adequate treatment exposure, the type of high-grade finding and time since treatment. A low-grade recurrence and an early high-grade recurrence cannot be treated as the same category.

In the EAU definition, adequate BCG includes at least five of the first six induction doses plus at least two doses of a second induction course or two of a three-dose maintenance course. High-grade Ta/T1 recurrence within six months, or CIS within twelve months, after adequate treatment is assessed within the unresponsive-disease criteria. These thresholds explain why accurate treatment records matter; they are not instructions to stop treatment yourself.

When unresponsive disease is confirmed, radical cystectomy is the standard and preferred option for suitable patients. Bladder-preserving options, local availability and clinical trials can be discussed when surgery is unsuitable or declined. Reading about a new drug does not establish that it is approved or appropriate for you in Türkiye.

Post-BCG cytology also needs to be interpreted with treatment dates. Moulavasilis and colleagues examined the relationship between Paris System categories and tissue findings after BCG. An atypical or suspicious result should be related to planned cystoscopy and, when needed, tissue assessment rather than dismissed solely because BCG was given.

References for this section: EAU. Non-muscle-invasive Bladder Cancer: Disease Management. Moulavasilis N, Stravodimos K, Meletis E, et al. The Paris system classification for urinary cytology in patients under bacillus Calmette-Guerin treatment. Diagn Cytopathol. 2022;50(6):289-294.

Frequently asked questions

Is BCG chemotherapy?

BCG is intravesical immunotherapy. It differs from intravesical chemotherapy drugs and from systemic treatment given into a vein.

Should I wait two days if I develop fever after BCG?

No. Seek immediate help for a temperature of 38°C or higher, severe chills, shortness of breath or significant deterioration. Follow any earlier-contact instructions from your own treatment team.

Do side effects prove BCG is effective?

No. The severity of side effects cannot be equated with an individual's treatment success. Response is assessed at the planned follow-up examinations.

Sources

1. European Association of Urology. EAU. Non-muscle-invasive Bladder Cancer: Disease Management [Internet]. Available from: https://uroweb.org/guidelines/non-muscle-invasive-bladder-cancer/chapter/disease-management
2. University College London Hospitals NHS Foundation Trust. BCG treatment for bladder cancer [Internet]. Available from: https://www.uclh.nhs.uk/patients-and-visitors/patient-information-pages/intravesical-immunotherapy-bcg
3. Cancer Institute NSW, eviQ. Patient information — Bladder cancer: Intravesical BCG [Internet]. Available from: https://www.eviq.org.au/medical-oncology/urogenital/bladder-and-urothelial/607-bladder-intravesical-bcg/patient-information
4. European Association of Urology. EAU. Non-muscle-invasive Bladder Cancer: Follow-up of Patients with NMIBC [Internet]. Available from: https://uroweb.org/guidelines/non-muscle-invasive-bladder-cancer/chapter/followup-of-patients-with-nmibc
5. Oddens J, Brausi M, Sylvester R, Bono A, van de Beek C, van Andel G, et al. Final results of an EORTC-GU cancers group randomized study of maintenance bacillus Calmette-Guérin in intermediate- and high-risk Ta, T1 papillary carcinoma of the urinary bladder: one-third dose versus full dose and 1 year versus 3 years of maintenance. Eur Urol. 2013;63(3):462-72. doi:10.1016/j.eururo.2012.10.039 · PubMed
6. Lamm DL, Blumenstein BA, Crissman JD, Montie JE, Gottesman JE, Lowe BA, et al. Maintenance bacillus Calmette-Guerin immunotherapy for recurrent TA, T1 and carcinoma in situ transitional cell carcinoma of the bladder: a randomized Southwest Oncology Group Study. J Urol. 2000;163(4):1124-9. doi:10.1016/s0022-5347(05)67707-5 · PubMed
7. Grimm MO, van der Heijden AG, Colombel M, Muilwijk T, Martínez-Piñeiro L, Babjuk MM, et al. Treatment of High-grade Non-muscle-invasive Bladder Carcinoma by Standard Number and Dose of BCG Instillations Versus Reduced Number and Standard Dose of BCG Instillations: Results of the European Association of Urology Research Foundation Randomised Phase III Clinical Trial "NIMBUS". Eur Urol. 2020;78(5):690-698. doi:10.1016/j.eururo.2020.04.066 · PubMed
8. Brausi M, Oddens J, Sylvester R, Bono A, van de Beek C, van Andel G, et al. Side effects of Bacillus Calmette-Guérin (BCG) in the treatment of intermediate- and high-risk Ta, T1 papillary carcinoma of the bladder: results of the EORTC genito-urinary cancers group randomised phase 3 study comparing one-third dose with full dose and 1 year with 3 years of maintenance BCG. Eur Urol. 2014;65(1):69-76. doi:10.1016/j.eururo.2013.07.021 · PubMed
9. Moulavasilis N, Stravodimos K, Meletis E, Levis P, Leftheriotis V, Lazaris A, et al. The Paris system classification for urinary cytology in patients under bacillus Calmette-Guerin treatment. Diagn Cytopathol. 2022;50(6):289-294. doi:10.1002/dc.24952 · PubMed