Radical cystectomy compared to intravesical BCG immunotherapy for high-risk non-muscle invasive bladder cancer – is there a long-term survival difference? A Swedish nationwide analysis

Abstract

Objectives

High-risk non-muscle invasive urinary bladder cancer (NMIBC) presents an increased risk of progression and cancer death. To reduce these risks, two different treatments are recommended – BCG or radical cystectomy (RC). The purpose of this study is to analyze cancer-specific survival of these two initial treatments.

Materials and Methods

BladderBaSe links information from the SNRUBC from 1997 to 2014, with a number of national healthcare and demographic registers. BCG was used for 3,862 patients (399 had delayed RC), while 687 had initial RC. Propensity scores were used to match the patients treated with RC and with relevant variables such as age, gender, and tumor stage with the same number treated with BCG (673 each arm). In a further comparison, an instrumental variable analysis using hospital strategy as the instrument was used.

Results

The 5-year cancer-specific survival chance was higher for the BCG group than it was for the initial RC group, 87 vs 71%, respectively. In the population with propensity score matching, 78 died from cancer in the BCG group during follow-up and 162 in the RC group. In the instrumental variable analysis, the multivariate adjusted risk difference of cancer-specific death 2 years after diagnosis was 32 per 100 treated patients, in favor of the BCG group.

Conclusions

BCG therapy had better cancer-specific survival than RC also when two different statistic methods were used to try to control for confounding. A prospective randomized trial will be necessary to rule out that selection is a major factor for the outcome.

Keywords:

• High-risk non-muscle invasive bladder cancer
• intravesical BCG immunotherapy
• radical cystectomy
• long-term survival

Acknowledgments

Christel Häggström, department of surgical sciences, Uppsala University and Lars Lindhagen, Uppsala Clinical Research Center, Uppsala University for statistical advice.

This project was made possible with help of the data collected in the Swedish National Register for Urinary Bladder Cancer (SNRUBC) and we would like to thank the members of the SNRUBC: Viveka Ströck, Firas Abdul-Sattar Aljabery, Amir Sherif, Abolfazl Hosseini-Aliabad, Truls Gårdmark, Fredrik Liedberg and Staffan Jahnson.

Author contributions

Eugen Wang had full access to all the data in the study and takes responsibility for the integriy of the data and the accuracy of the data analysis. Study concept and design: Malmström. Acquisition of data: Gårdmark, Malmström. Analysis and interpretation of data: Wang, Larsson, Malmström. Drafting of the manuscript: Wang, Larsson, Gårdmark, Malmström. Critical revision of the manuscript for important intellectural content: Wang, Larsson, Gårdmark, Malmström. Statistical analysis: Larsson.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded by Center for Clinical Research, Sörmland, Uppsala University and Schmekel funder for Urological research.