Patients and treatment
A prospective, randomized, controlled, non-blinded study, conducted at West China Hospital, Sichuan University, compared intravesical BCG and EPI treatment. The study was approved by the ethics committee of the Center for Drug Evaluation of the National Medical Products Administration (China) and Ethics Committee of West China Hospital.
The inclusion criteria were: age 20–75 years; TUR-BT with completely tumor resection. BT was completely resected with pathologically proven intermediate or high-risk non-muscle invasive bladder urothelium carcinoma according to the European Association of Urology (EAU) guidelines for risk stratification of NMIBC(2).
Exclusion criteria were: a. Eastern Cooperative Oncology Group performance status score >1; b. patients with active tuberculosis or receiving treatment for anti-tuberculous; c. immune deficiency or undergoing immunosuppressive therapy; d. severe complication (e.g., serious cardiovascular and cerebrovascular disease), or presence of other types of cancer; e. previous diagnosis with muscle-invasive bladder cancer; f. patients underwent treatment (e.g., chemotherapy, radiotherapy or immunotherapy) during the previous 4 weeks which may influence the research results; f. serious intraoperative and postoperative complications (e.g., bladder perforation, serious postoperative hematuresis, bladder irritation, etc.); and g. patients not suitable to receive treatment or not able to participate in our trial due to pregnancy, severe disability, serious psychological problems, etc.
Post-operative immediate irrigation with EPI 50 mg was performed within 24 h after TUR-BT. After confirming the presence of intermediate- or high-risk NMIBC according to surgical findings and the final pathological report, patients who participated in the study were randomized into three bladder irrigation groups: a. BCG 19 group (BCG 120 mg weekly for six times, followed by biweekly irrigation for three times, and then monthly for 10 times, for a total of 19 irrigations with BCG); b. BCG 15 group (BCG 120 mg weekly for six times, followed by irrigations for the first 3 weeks and at 3, 6, and 12 months after surgery, for a total of 15 irrigations with BCG); and c. EPI 18 group (EPI 50 mg weekly for eight times, followed by monthly irrigation for 10 times, for a total of 18 irrigations). The randomization was performed within 14 days after surgery, at a 2:2:1 ratio (Das for IWRS Version 5.0, BioVoice & BioGuider, Beijing, China). Subsequently, irrigation was initiated on day 14 post operation and the duration of treatment was 1 year.
Follow-up and outcomes
For intermediate-risk patients, cystoscopy was performed 3 and 6 months after surgery, then biannually until 5 years. For high-risk patients, cystoscopy was performed trimonthly until 2 years after surgery, then biannually until 5 years. Urinalysis was performed prior to each irrigation. Patients were followed up until recurrence, progression, or discontinuation of treatment for any reason. Adverse effects were recorded at each follow-up according to the Common Terminology Criteria for Adverse Events Version 4.0(6).
The initiation time was the day TUR-BT was performed. The primary end point was recurrence during follow-up, while the secondary end point was progression to muscle-invasive bladder cancer or therapy-related discontinuation of treatment. Recurrence-free survival (RFS) and progression-free survival (PFS) times were recorded. BCG failure and intolerance were recorded according to the definitions of the EAU (2).
Data collection
Recorded clinical variants included gender, age and smoking history. Intraoperative recordings included tumor size, site, and number. Tumor histopathological type, T stage (8th American Joint Committee on Cancer TNM classification system)(7), tumor grade (2004 World Health Organization grading system), and carcinoma in situ status. All pathological reports were provided by the Pathology Department of West China Hospital.
Statistical methods
Differences in survival between two or more subgroups were evaluated using log-rank tests. Univariate and multivariate Cox regression analyses were performed to determine the clinicopathological parameters associated with the recurrence of patients with NMIBC. Patients were stratified using the European Organization for Research and Treatment of Cancer (EORTC) risk tables(8) and the Spanish Urological Club for Oncological Treatment (CUETO) scoring model(5). The predictive ability of these outcome prediction models was evaluated using the concordance index (c-index)(9).
Statistical analyses were performed using the SPSS Statistics version 25 (IBM, Armonk, NY, USA) and The R Programming Language 3.5.0 software (The R Foundation, Vienna, Austria). A P-value <0.05 denoted statistical significance.