Non-Muscle-Invasive Bladder Cancer: Treatment Options and When Immunotherapy Is Used

Research-informed explainer — last updated April 12, 2026

About 75% of bladder cancers are diagnosed at a non-muscle-invasive stage, where the tumor has not grown into the muscular wall of the bladder — and with the right treatment protocol, many patients can keep their bladder while controlling their disease. Understanding whether your tumor is low-, intermediate-, or high-grade determines whether you receive a single post-operative treatment or years of immunotherapy with BCG.

This article draws on research from four specialists in bladder cancer. Yair Lotan, MD, at Parkland Health and Hospital System in Frisco, Texas, published the leading epidemiology review of urothelial bladder cancer (cited over 2,100 times), the Lancet bladder cancer primer, and recurrence and progression data for non-muscle-invasive disease. James McKiernan, MD, Director of Urologic Oncology at NewYork-Presbyterian/Columbia, co-authored the AUA/SUO Non-Muscle-Invasive Bladder Cancer guideline (cited over 1,350 times) — the standard-of-care document that governs how patients are stratified and treated. Adam Feldman, MD, Associate Professor at Harvard Medical School and Massachusetts General Hospital, published the long-term outcomes data on trimodality (bladder-preserving) therapy versus radical cystectomy, which is critical for patients whose disease progresses. Laura Bukavina, M.D., at Cleveland Clinic, published the 2023 systematic review of bladder cancer epidemiology and risk factors.

What is non-muscle-invasive bladder cancer?

The bladder wall has several layers. Non-muscle-invasive bladder cancer (NMIBC) means the tumor is confined to the innermost layers — the urothelium (Ta, Tis) or the lamina propria just beneath it (T1). Stage T2 or higher means the cancer has invaded the muscle layer (detrusor), which changes the treatment algorithm entirely.

NMIBC is further divided by grade:

• Low-grade NMIBC (Ta LG): Slow-growing, rarely progresses to muscle invasion. Recurrence is common (50-70% at 5 years) but progression to muscle invasion occurs in fewer than 5% of patients.
• High-grade NMIBC (Ta HG, T1, or CIS): Much higher risk. Carcinoma in situ (CIS) — a flat, high-grade lesion — carries a 40-80% risk of muscle invasion without effective treatment. T1 high-grade disease has a 30-50% risk of progression within 5 years.

Step 1: TURBT — transurethral resection of the bladder tumor

For all NMIBC, the first intervention is transurethral resection of the bladder tumor (TURBT). This is a procedure done through the urethra, under anesthesia, in which a urologist uses a resectoscope to remove visible tumor tissue and cauterize the base. Pathology of the resected specimen confirms grade, depth of invasion, and whether muscle (detrusor) was included in the specimen.

A complete, quality TURBT is essential — incomplete resection is one of the main drivers of early recurrence. For T1 high-grade disease, re-TURBT at 4 to 6 weeks is often recommended because residual tumor or understaging is found in 20-50% of cases at repeat resection.

Step 2: Intravesical therapy — BCG or chemotherapy

Based on the AUA/SUO NMIBC guideline co-authored by Dr. McKiernan, patients are stratified into low, intermediate, and high risk to guide intravesical (bladder-instilled) treatment:

Low-risk (single, small, low-grade Ta tumor): A single immediate postoperative instillation of intravesical mitomycin C (MMC) given within hours of TURBT reduces the risk of recurrence by approximately 40% by destroying circulating tumor cells. No maintenance therapy is typically needed.

Intermediate-risk (recurrent or multifocal low-grade, or low-grade T1): Induction BCG (6 weekly instillations) followed by 1 year of maintenance therapy. Alternatively, intravesical MMC or gemcitabine/docetaxel for patients who cannot tolerate BCG.

High-risk (high-grade Ta, T1 high-grade, or CIS): Full induction BCG (6 weekly instillations) followed by 3-year maintenance BCG (3 weekly instillations at months 3, 6, 12, 18, 24, 30, 36). BCG is an immunotherapy — it instills attenuated Mycobacterium bovis directly into the bladder, triggering a local immune response that clears residual cancer cells and prevents recurrence and progression.

What happens if BCG fails?

BCG-unresponsive disease — defined as high-grade recurrence within 6 months of adequate BCG — carries a high risk of progression and historically has required radical cystectomy. In recent years, several alternatives have gained FDA approval for BCG-unresponsive CIS:

• Pembrolizumab (Keytruda): PD-1 checkpoint inhibitor given intravenously; complete response rate approximately 41% at 3 months in the KEYNOTE-057 trial.
• Nadofaragene firadenovec (Adstiladrin): Gene therapy delivered intravesically; complete response rate approximately 51% at 3 months.
• Erdafitinib: For FGFR-altered tumors (about 20% of patients).
• Gemcitabine/docetaxel combination: Off-label but widely used; response rates 35-55% in salvage setting.

Patients with BCG-unresponsive disease who are not candidates for or refuse cystectomy should discuss these options with a high-volume bladder cancer center.

When is radical cystectomy needed?

Cystectomy — removal of the entire bladder, prostate (in men), or uterus and anterior vaginal wall (in women) — becomes the standard recommendation when:

• Muscle-invasive disease (T2 or higher) is confirmed
• BCG-unresponsive high-grade NMIBC where bladder-preserving options have failed
• T1 high-grade disease with adverse pathological features (lymphovascular invasion, variant histology, multifocal CIS)

Bladder-preserving trimodality therapy: when it is a valid alternative

For patients with muscle-invasive bladder cancer who refuse cystectomy or are medically unfit, trimodality therapy (TMT) — maximal TURBT followed by concurrent chemotherapy and radiation — can preserve the bladder while achieving cancer control. The updated Massachusetts General Hospital series published by Dr. Feldman's group reported 5-year overall survival of approximately 57% and disease-specific survival of 66% in carefully selected muscle-invasive patients. A 2023 multi-institutional propensity-matched analysis comparing TMT to radical cystectomy found no statistically significant difference in overall survival for selected patients with T2 disease.

TMT is not appropriate for everyone — it requires complete or near-complete TURBT, no hydronephrosis, and bladder capacity adequate for surveillance. Incomplete responders need cystectomy.

Surveillance after treatment

Because bladder cancer has among the highest recurrence rates of any cancer (50-70% for NMIBC at 5 years, per Dr. Lotan's epidemiology work), surveillance is lifelong:

• Cystoscopy at 3 months after treatment, then every 3-6 months for 2 years, then annually
• Urine cytology at each visit
• Upper tract imaging (CT urogram) every 1-2 years for high-risk patients

Questions to ask your doctor

• What is my exact stage and grade — am I Ta, T1, or CIS, and is the tumor low or high grade?
• Was muscle included in the TURBT specimen, and do I need a re-TURBT?
• Am I high-risk enough to warrant BCG, and is there a BCG shortage that would affect my treatment?
• How often will I need cystoscopy surveillance, and for how long?
• If my cancer is BCG-unresponsive, what bladder-sparing options am I eligible for before considering cystectomy?
• Should I be evaluated at a high-volume academic bladder cancer center?

The bottom line

Non-muscle-invasive bladder cancer is treatable, but it demands rigorous surveillance because recurrence is the rule, not the exception. Low-grade tumors require a single instillation and monitoring; high-grade and CIS require years of BCG immunotherapy and close follow-up. Disease that does not respond to BCG is a clinical emergency — either new FDA-approved salvage therapies or radical cystectomy must be considered promptly. When muscle invasion occurs, the choice between radical cystectomy and bladder-preserving trimodality therapy depends on tumor characteristics and patient fitness, not on patient preference alone.