Poster Presentation 2025 National Cancer Survivorship Conference

The non-muscle invasive bladder cancer symptom index (NMIBC-SI) is valid and reliable. (#160)

Claudia Rutherford 1 2 , Margaret-Ann Tait 1 2 , Daniel SJ Costa 3 , Madeleine King 3 , David P Smith 2 , Shomik Sengupta 4 5 6 , Manish I Patel 6 7 8
  1. Sydney Nursing School, University of Sydney, Sydney, NSW, Australia
  2. The Daffodil Centre, The University of Sydney, a Joint Venture with Cancer Council New South Wales, Sydney, NSW, Australia
  3. School of Psychology, University of Sydney, Sydney, NSW, Australia
  4. Eastern Health Clinical School, Monash University, Melbourne, Vic, Australia
  5. Department of Urology, Eastern Health, Box Hill, Vic, Australia
  6. ANZUP Cancer Trials Group, Barangaroo, NSW, Australia
  7. Sydney Medical School, Specialty of Surgery, University of Sydney, Sydney, NSW, Australia
  8. Department of Urology, Westmead Hospital, Westmead, NSW, Australia

Aims 

Non-muscle invasive bladder cancer (NMIBC) is a lifelong chronic condition requiring treatment and regular cystoscopies. Patient-reported outcomes (PROs) are important treatment considerations for chronic conditions; however, existing PRO measures inadequately cover NMIBC-specific symptoms and side-effects of current treatments. To address this, we developed and psychometrically evaluated a patient-reported NMIBC-Symptom Index (NMIBC-SI). 

Methods 

A conceptual framework of NMIBC-PROs was developed through a systematic review and interviews with patients (n=26) and clinicians (n=20). NMIBC-PROs were phrased as questions and pre-tested in cognitive interviews (n=12), producing a draft-NMIBC-SI, which was administered to 220 NMIBC-patients on active treatment. Index items were chosen based on item-level analysis for acceptability and expert consensus (n=9) on clinical relevance. The final NMIBC-SI contains a Core-index (23-items) and treatment-specific indexes: Cystoscopy (6-items) and Intravesical therapy (10-items).

A longitudinal study of newly diagnosed NMIBC patients (16 sites, 5 countries) administered the NMIBC-SI at baseline, post-surgery, post-induction, and 1-year. Composite model goodness of fit (CFI>0.9) assessed construct validity. Test-retest reliability (ICC>0.7) evaluated stability. Change from baseline, and between-group differences, assessed responsiveness and clinical validity (p<0.05).  

Results 

Of 232 participants (176 male; mean age 68y), 182 completed the NMIBC-SI at baseline and follow-up. Composite analysis supported a two-composite model containing the core and cystoscopy indexes (CFI=0.948). There were insufficient participant numbers to test the intravesical index. Stability reliability was supported (ICC range 0.89-0.91). Compared with baseline, Core-index symptom scores worsened post-surgery (t(401)=5.53,p<0.001), and improved post-induction (t(562)=2.89,p=0.004) and at 1-year (t(616)=3.36,p<0.001); Cyst-index showed higher symptom burden post-surgery (t(229)=7.15,p<0.001) and post-induction (t(326)=2.85,p=0.005), all supporting responsiveness. Core-index discriminated between no-treatment vs any-treatment groups (t(174)=2.89,p=0.004), and Cyst-index discriminated between surgery+chemo vs surgery alone (t(89)=2.98,p=0.004), demonstrating clinical validity.

Conclusions 

The NMIBC-SI is a comprehensive and valid assessment of patient-reported NMIBC symptoms and treatment side-effects suitable for clinical research and clinical practice to improve treatment decisions and patient outcomes.