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

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.