(UroToday.com) The 2024 European Association of Urology (EAU) annual meeting featured a non-muscle invasive bladder cancer session and a presentation by Dr. Roberto Contieri discussing follow-up strategies for EAU 2021 intermediate-risk non-muscle invasive bladder cancer.
The current EAU non-muscle invasive bladder cancer guidelines categorize patients into four groups based on their risk of progression. While distinct follow-up recommendations are available for the low-risk and high-risk groups, there is a lack of a specific follow-up protocol for the non-muscle invasive bladder cancer intermediate-risk group patients. The aim of this study presented at EAU 2024 was to identify a new subgroup of higher-risk intermediate-risk patients who may require a more stringent follow-up schedule.
Patients with primary Ta-T1 non-muscle invasive bladder cancer treated at 17 hospitals between 1990 and 2018 and meeting the EAU21 definition of intermediate-risk based on the WHO 1973 grading system were included. Using a multivariable Cox regression model stratified by institution, Dr. Contieri tested risk factors for time to first recurrence among T-stage, grade, multifocality, size (> 3 cm), and age (> 70 years). The model was adjusted for a single instillation of intravesical chemotherapy, induction intravesical chemotherapy, and induction BCG. Based on this multivariable Cox regression model, the investigators defined two subgroups:
- Intermediate-risk-low-risk-of-recurrence
- Intermediate-risk-high-risk-of-recurrence
Kaplan-Meier curves were used to estimate recurrence-free survival and progression-free survival. Additionally, they assessed the probability of first recurrence at different time points in these subgroups with Locally Weighted Scatterplot Smoothing.
A total of 2,086 patients with intermediate-risk-non-muscle invasive bladder cancer were analyzed. Over a median follow-up of 46 months (IQR 22.5-85), 879 recurred and 87 progressed. The multivariable Cox regression model indicated that multifocality (HR 1.9, 95% CI 1.6-2.2; p < 0.01) and size >3 cm (HR 1.5, 95% CI 1.3-1.8; p<0.01) were significantly associated with the time to first recurrence. Patients with at least one of these risk factors were included in the newly defined intermediate-risk-high-risk-of-recurrence subgroup (n = 999, 48%). The 5-year recurrence-free survival was 60% (95% CI 56-63%) for intermediate-risk-low-risk-of-recurrence and 42% (95% CI 38-45%) for intermediate-risk-high-risk-of-recurrence patients. The following figure shows the probability of first recurrence stratified by intermediate-risk-subgroup, indicating that during the first 5 years, intermediate-risk-high-risk-of-recurrence patients have a higher probability of first recurrence than intermediate-risk-low-risk-of-recurrence patients:
Overall, the risk of progression was small (5-year progression-free survival: 96%), with no statistical difference among the subgroups (p = 0.08).
Dr. Contieri concluded his presentation discussing follow-up strategies for EAU 2021 intermediate-risk non-muscle invasive bladder cancer with the following conclusions:
- Patients with intermediate-risk-non-muscle invasive bladder cancer can be stratified into low (Intermediate-risk-low-risk-of-recurrence) and high (intermediate-risk-high-risk-of-recurrence) risk of first recurrence
- These findings could be considered for future treatment strategies, follow-up recommendations, and within investigational trials
Presented by: Roberto Contieri, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
Written by: Zachary Klaassen, MD, MSc - Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, WellStar MCG Health, @zklaassen_md on Twitter during the 2024 European Association of Urology (EAU) annual congress, Paris, France, April 5th - April 8th, 2024