2390P - Correlation between overall survival and bladder-intact event-free survival in cystectomy-ineligible/refusal muscle-invasive bladder cancer patients in Sweden

Background

Radical cystectomy (RC) is currently the recommended treatment for muscle-invasive bladder cancer (MIBC) in Europe and the US. In Sweden, patients unfit or refusing RC are offered bladder-sparing curative or palliative treatment, such as radiotherapy and/or chemotherapy. Bladder-intact event-free survival (BI-EFS) is defined as survival from treatment initiation until confirmed refractory/recurrent MIBC or nodal/metastatic disease, RC, or death, and has been introduced as a primary endpoint in clinical trials. This study evaluated the correlation between BI-EFS and overall survival (OS) in RC-ineligible/refusal MIBC patients in real world in Sweden.

Methods

Patients diagnosed with T2-T4aN0M0 MIBC who subsequently received radiotherapy and/or chemotherapy during 2006-2017 in Sweden were identified in population-based registers and followed until 2018. Exclusion criteria included other urothelial carcinoma prior to MIBC diagnosis and upfront RC upon diagnosis. An iterative multiple imputation method for censored outcomes was used to measure the normal scores rank correlation between BI-EFS and OS.

Results

A total of 337 patients were included in the study. The median age at diagnosis was 77 (IQR 71-82) years and 76% of patients were men. At diagnosis, 286 patients presented with T2 and 51 with T3/T4a stage. There was no significant difference in age at diagnosis between T2 and T3/T4a patients. Overall, the median OS and BI-EFS were 1.04 (95%CI 0.88-1.27) and 0.77 (95%CI 0.65-0.99) year, respectively. T2 and T3/T4a patients had a median OS of 1.11 (95%CI 0.91-1.33) and 0.76 (95%CI 0.5-1.45) year, respectively; and a median BI-EFS of 0.85 (95%CI 0.71-1.05) and 0.5 (95%CI 0.22-0.98) year, respectively. Overall, the correlation between BI-EFS and OS was 0.82 (95%CI 0.77-0.85); for T2 and T3/4a patients, the correlation was 0.84 (95%CI 0.80-0.87) and 0.65 (95% CI 0.44-0.79), respectively.

Conclusions

BI-EFS was correlated with OS in RC-ineligible/refusal MIBC patients who received radiotherapy and/or chemotherapy. The strong correlation in all subgroups supports the use of BI-EFS as a surrogate endpoint for OS in similar patient populations.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Schain Research AB.

Funding

This study was undertaken by Schain Research AB sponsored by Janssen Global Services, Llc.

Disclosure

S. Baculea, S. Côté: Financial Interests, Personal, Full or part-time Employment: Janssen Global Services, Llc; Financial Interests, Personal, Stocks/Shares: Janssen Global Services, Llc. S. Spigelman: Financial Interests, Personal, Full or part-time Employment: Janssen Research & Development, Llc; Financial Interests, Personal, Stocks/Shares: Janssen Research & Development, Llc. All other authors have declared no conflicts of interest.