EAU 2024: The International Bladder Cancer Group Intermediate-Risk Non-Muscle Invasive Bladder Cancer (IBCG IR-NMIBC) Scoring System Predicts the Need for Intervention for Patients on Active Surveillance

(UroToday.com) The 2024 European Association of Urology (EAU) annual congress held in Paris, France between April 5th and 8th was host to a non-muscle invasive bladder cancer (NMIBC) poster session of studies evaluating the benefits and harms of various treatment options. Dr. Roberto Contieri presented the results of an analysis evaluating the International Bladder Cancer Group Intermediate-risk Non-muscle Invasive Bladder Cancer (IBCG IR-NMIBC) scoring system to predict the need for intervention among patients on active surveillance.

Dr. Contieri noted that active surveillance remains an option for intermediate risk NMIBC. The investigators evaluated whether the IBCG IR-NMIBC scoring system can predict the need for surgical intervention among patients with low grade NMIBC managed with active surveillance. 

The investigators utilized the Bladder Italian Active Surveillance (BIAS) registry, a prospective study of LG Ta/T1 NMIBC patients managed with active surveillance. Patients with the following disease characteristics were recommended for active surveillance:

  • Low-grade papillary disease
  • ≤5 suspicious lesions at recurrence
  • Each lesion ≤1 cm in diameter
  • Absence of gross hematuria
  • Negative urinary cytology

Delayed TURBT was offered for patients who did not meet these strict eligibility criteria or upon patient request. The primary endpoint was the rate of delayed TURBT in this cohort. Multivariable Cox proportional-hazards analysis was used to evaluate predictors of delayed TURBT following the initial period of active surveillance.

This analysis included a total of 163 LG Ta/T1 patients. At a median follow-up of 24 months (IQR: 8 – 60), a delayed TURBT was performed in 109/163 patients. Patients without any, 1, and ≥2 IBCG IR-NMIBC risk factors accounted for 20%, 58%, and 22% of patients, respectively. Patients without any risk factors were three-fold more likely to continue on active surveillance, compared to patients with ≥3 risk factors at 24 months follow-up (61% versus 19%). 

Multivariable Cox regression analysis adjusted for age and stage demonstrated that the IBCG scoring system was significantly associated with the rate of delayed TURBT:

  • 1 – 2 risk factors: HR= 1.8, 95% CI= 1.06 – 3.06, p=0.030
  • ≥3 risk factors: HR= 3.76, 95% CI= 2.07 – 6.81, p<0.001 

Dr. Contieri concluded that the IBCG IR-NMIBC scoring system can be used to predict the rate of discontinuing active surveillance in favor of delayed TURBT in a cohort of patients with low-grade Ta/T1 disease. This may aid in the counseling of such patients considering active surveillance.

Presented by: Roberto Contieri, MD, Humanitas University, Department of Biomedical Sciences, Milan, Italy

Written by: Rashid Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2024 European Association of Urology (EAU) annual congress, Paris, France, April 5th – April 8th, 2024