Circulating Basophils as a Prognostic Marker for Response to Bacillus Calmette-Gurin

There is a need for accessible biomarkers to refine the treatment of patients with nonmuscle invasive bladder cancer (NMIBC). This 2-center retrospective study evaluates the circulating basophil count as a biomarker for patients receiving Bacillus-Calmette Guerin (BCG) for NMIBC. We found higher circulating basophils independently predicted both recurrence and progression, highlighting its potential as a biomarker for patients with NMIBC. Purpose: To predict recurrence and progression in non-muscle-invasive bladder cancer (NMIBC) patients receiving bacillus Calmette -Guerin (BCG), we evaluated circulating basophils as a biomarker that could be detected from the complete blood count. Patients and Methods: We use a pooled cohort of patients from the Centre Hospitalier Universitaire de Quebec -Universite Laval (2016-2020) and the Vancouver General Hospital (2010-2018) where a complete blood count was available before transurethral resection of bladder tumor (TURBT) of a high-grade NMIBC and subsequent BCG. Descriptive statistics described the cohort based on the dichotomous presence or absence of basophils on the complete blood count. Kaplan -Meier estimates and a log-rank test compared recurrence-free survival (RFS) and progression -free survival (PFS), with multivariable cox regression analysis used to estimate proportional hazard ratios. Results: The study cohort included 261 patients, with a median follow-up of 31.5 months (interquartile range 18.1-45.0 months). The median age was 74.0 years and 16.8% were female. Circulating basophils were detectable in 49 (18.9%) patients. Both RFS and PFS were significantly lower in patients with detectable basophils. Multivariable analysis demonstrated detectable basophils were an independent predictor of both recurrence (HR = 1.85; 95% confidence interval [CI] 1.20-2.85; P = .01) and progression (HR = 2.29; 95% CI 1.14-4.60; P = .02). Conclusion: Our results confirm that baseline levels of circulating basophils are an immunological biomarker to predict recurrence and progression of NMIBC.