Evaluating the Protective Effect of Intravesical Bacillus Calmette-Guerin against SARS-CoV-2 in Non-Muscle Invasive Bladder Cancer Patients: A Multicenter Observational Trial

Simple Summary The transurethral resection of bladder tumors followed by intravesical Bacillus Calmette-Guerin (BCG) instillations represents the standard treatment for high-risk and selected intermediate-risk non-muscle invasive bladder cancer (NMIBC) patients. We hypothesized that intravesical BCG might be protective against symptomatic SARS-CoV-2 infection, especially in those patients who experienced systemic adverse events during BCG treatment. We tested our hypothesis in a large multicenter cohort of NMIBC patients treated with adjuvant intravesical BCG in the year preceding the first and second waves of the SARS-CoV-2 pandemic at two tertiary urological centers in Northern Italy. We aim to evaluate the potential protective role of intravesical Bacillus Calmette-Guerin (BCG) against SARS-CoV-2 in patients with non-muscle invasive bladder cancer (NMIBC). Patients treated with intravesical adjuvant therapy for NMIBC between January 2018 and December 2019 at two Italian referral centers were divided into two groups based on the received intravesical treatment regimen (BCG vs. chemotherapy). The study's primary endpoint was evaluating SARS-CoV-2 disease incidence and severity among patients treated with intravesical BCG compared to the control group. The study's secondary endpoint was the evaluation of SARS-CoV-2 infection (estimated with serology testing) in the study groups. Overall, 340 patients treated with BCG and 166 treated with intravesical chemotherapy were included in the study. Among patients treated with BCG, 165 (49%) experienced BCG-related adverse events, and serious adverse events occurred in 33 (10%) patients. Receiving BCG or experiencing systemic BCG-related adverse events were not associated with symptomatic proven SARS-CoV-2 infection (p = 0.9) nor with a positive serology test (p = 0.5). The main limitations are related to the retrospective nature of the study. In this multicenter observational trial, a protective role of intravesical BCG against SARS-CoV-2 could not be demonstrated. These results may be used for decision-making regarding ongoing and future trials.

Automated summary

This study aimed to evaluate the potential protective role of intravesical BCG against SARS-CoV-2 in NMIBC patients. The results showed that BCG treatment and systemic BCG-related adverse events were not associated with SARS-CoV-2 infection. The main limitation of this study is its retrospective nature.