Development of a Prediction Tool for Exclusive Locoregional Recurrence After Radical Cystectomy in Patients With Muscle-Invasive Bladder Cancer

BACKGROUND: Limited information is available about the pattern of relapse after perioperative chemotherapy with radical cystectomy (RC) vs. RC alone in muscle-invasive bladder cancer. PATIENTS AND METHODS: Data from 1082 patients of the Retrospective International Study of Invasive/Advanced Cancer of the Urothelium database, treated from February 1990 to December 2013 at 27 centers in the United States, Europe, Israel, and Canada, were collected. Locoregional relapse was defined as any pelvic lymph node or soft tissue-only recurrences. Cumulative incidence methods were used to estimate time to locoregional relapse (TTR_L). Cox regression analyses were performed and a nomogram for 12-month locoregional relapse-free survival (RFS) was developed. The nomogram was applied to an external data set (n = 1021). RESULTS: A total of 517 patients (47.8%) developed a relapse: 177 (16.4%) exclusive locoregional relapse. In multivariable analyses, perioperative chemotherapy was associated with longer TTR_L (P < .001). Other factors were nonurothelial histology (P = .013), pT-stage (P < .001), and surgical margins (P < .001). The concordance index of the model was 0.681 (95% bootstrapped confidence interval, 0.666-0.716). Risk group categories were obtained according to nomogram tertiles. Despite, overall, observed locoregional RFS in the validation cohort exceeding predicted results, for high-risk patients (80 points or less, lowest nomogram tertile) observed 12-month RFS was similar between development and validation cohorts (60.1% and 66.6%). The study is limited by its retrospective nature. CONCLUSION: In the largest study, to our knowledge, that analyzed locoregional recurrences after RC, we propose a risk prediction tool for exclusive locoregional failures that might be suitable for clinical studies. Patients best suited for adjuvant radiotherapy might be those within the lowest nomogram tertile. Prospective trials are needed to validate findings.