From the Guidelines
Surveillance for non-muscle invasive bladder cancer (NMIBC) should follow a risk-stratified approach based on tumor characteristics, with the most recent guidelines recommending a tailored schedule for low-, intermediate-, and high-risk patients 1. The goal of surveillance is to detect recurrence and progression early, allowing for prompt intervention and potentially preventing progression to muscle-invasive disease.
Risk Stratification
The risk stratification is based on tumor characteristics, including:
- Tumor size: Tumors measuring 3 cm are associated with decreased time to first recurrence and time to progression compared with tumors measuring <3 cm 1.
- Tumor multifocality: Multiple tumors are identified in >40% of cases and are associated with higher rates of recurrence and decreased time to first recurrence 1.
- Tumor grade: The World Health Organization (WHO)/International Society of Urological Pathology (ISUP) 2004 grading system is used to classify tumor grade (I-III) 1.
- Tumor stage: Most UCs of the bladder are superficial (75%), although NMIBC consists of a heterogeneous group including Ta (70%), T1 (20%), and Tis (10%) lesions 1.
Surveillance Schedule
For low-risk NMIBC, cystoscopy should be performed at 3 months after initial treatment, then every 6-12 months for 5 years 1. For intermediate-risk NMIBC, cystoscopy and urine cytology are recommended at 3 months, then every 3-6 months for 2 years, every 6-12 months during years 3-4, and annually thereafter 1. High-risk NMIBC requires more intensive surveillance with cystoscopy and cytology every 3 months for 2 years, every 6 months for years 3-4, and annually thereafter 1. Upper tract imaging with CT urography or IVP should be performed every 1-2 years for high-risk patients 1.
Importance of Early Detection
Early detection of recurrence allows for prompt intervention, potentially preventing progression to muscle-invasive disease, which would require more aggressive treatments like radical cystectomy 1. The recurrence rates for NMIBC are high, ranging from 50-70%, with most recurrences happening within the first two years 1. Progression to muscle-invasive disease occurs in 10-30% of high-risk patients, highlighting the importance of rigorous surveillance 1.
From the Research
Surveillance Protocol for Non-Muscle Invasive Bladder Cancer (NMIBC)
The recommended surveillance protocol for NMIBC is based on a risk-adapted approach, taking into account the risks of recurrence and progression 2, 3. The protocol involves a combination of:
- Cystoscopy
- Urine cytology
- Upper tract imaging
Risk Groups and Surveillance Schedules
Patients with NMIBC can be classified into low-risk, intermediate-risk, and high-risk groups 2, 4. The surveillance schedule for each group is as follows:
- Low-risk tumors: annual cystoscopy alone is sufficient, with no upper tract evaluations or cytology needed except at diagnosis 2, 4
- High-risk tumors: cystoscopy every 3 months for 2 years, 6 months for 2 years, and then annually, with cytology at frequent intervals, and imaging for upper tract evaluation at 1 year and then every 2 years 2
- Intermediate-risk tumors: subclassified according to the International Bladder Cancer Group recommendations, and followed up with a surveillance strategy similar to that of high-risk tumors if associated with certain findings (multiple tumors, size ≥3cm, early recurrence <1 year, frequent recurrences >1 per year) 2
Role of Urine Markers
Several urine markers have been developed for the detection of NMIBC, but their routine use has not been integrated into current guidelines due to high costs and the need for specialized laboratories 2, 5. Cystoscopy and urine cytology remain the gold-standard tests for detection of recurrent disease during follow-up 3, 5.
Key Considerations
The aim of the surveillance protocol is to minimize the therapeutic burden of a disease with high recurrence rates without missing progressing tumors 2. The choice of diagnostic tests should be based on their sensitivity and specificity, with first-line tests having high sensitivity and second-line tests having high specificity 2.