Preoperative absolute basophils count predicts recurrence and progression of non-muscle-invasive bladder cancer following bacillus Calmette-Guérin treatment
Raphaëlla Rosebush-Mercier1, Timo Nykopp2, Jonathan Fadel1, Bernhard J. Eigl3, Peter C. Black4, Paul Toren1.
1Department of Surgery, Faculty of Medicine - Université Laval, Québec, QC, Canada; 2Department of Surgery, University of Eastern Finland, Kuopio, Finland; 3Department of Medical Oncology, BC Cancer, Vancouver, BC, Canada; 4Department of Urologic Sciences, Faculty of Medicine - University of British Columbia, Vancouver, BC, Canada
Introduction: Intravesical bacillus Calmette-Guérin (BCG) is the main treatment to prevent relapse and progression of high-grade non-muscle-invasive bladder cancer (NMIBC). Th2-related cytokines in the tumor immune microenvironment have been shown to predict adverse response to BCG. Given the implication of basophils in this Th2 response, we sought to evaluate the association between basophil levels and outcomes following BCG treatment for high-grade NMIBC.
Methods: High-grade NMIBC patients were included if they received at least five of six BCG instillations and had a complete blood count (CBC) before transurethral resection of bladder tumor (TURBT). Data were pooled from CHU de Québec-Université Laval (2016–2020) and UBC (2010–2018). Descriptive statistics, Kaplan-Meier analysis, and Cox regression analyses evaluated the predictive value of detectable (vs. undetectable) absolute basophil levels on clinical outcomes. Multivariable regression analysis was conducted on relevant clinical and pathological variables, in addition to detectable basophil levels.
Results: Basophil levels were detectable at baseline in 42 of 217 (19%) patients. Patients with detectable basophils showed less carcinoma in situ and more >3 cm tumors. Recurrence and progression were observed in 84 (39%) and 27 (12%) patients, respectively. The median time to recurrence was 15 months in patients with detectable basophils and not reached in patients with undetectable basophils (p=0.003). Progression-free survival was lower among patients with detectable basophils (p=0.002). On multivariable regression analysis, the presence of detectable basophils significantly increased the risk of recurrence (hazard ratio [HR] 2.04, 95% confidence interval [CI] 1.27–3.32) and progression (HR 2.98, 95% CI 1.36–6.52).
Conclusions: The presence of basophils on the pre-TURBT CBC is an important predictor of the risk of disease progression or recurrence following BCG. As an available and inexpensive biomarker, it can help in clinical decision-making for patients with NMIBC.
