Chemoradiation versus cystectomy for locally advanced bladder cancer: A global, propensity-matched retrospective cohort study.

e16603 Background: Prior studies have attempted to determine whether chemoradiation is comparable to cystectomy for treatment of locally advanced bladder cancer. Some studies have shown no significant difference, while others indicate a small benefit in favor of cystectomy. The purpose of this study was to use the large, multi-institutional TriNetX database to evaluate for differences in overall survival and development of metastatic disease between the two treatments at five years. Methods: The TriNetX research database was used for this study. Two patient cohorts were created by utilizing International Classification of Disease-10 (ICD-10) codes and Current Procedural Terminology (CPT) codes. Both cohorts of patients were required to have a diagnosis of bladder cancer (C67) and were prohibited from having any known sites of metastatic disease (C78 or C79). The cystectomy cohort was constructed by using CPT codes 51590, 51595, or 51596. Chemoradiation treatment was identified by encounters for chemotherapy and radiation occurring on the same day (Z51.11 and Z51.0). The chemoradiation cohort was prohibited from having any cystectomy surgery, and the cystectomy cohort was prohibited from having had any radiation treatment. The cohorts were then balanced by propensity score matching and the greedy nearest neighbor algorithm for age, race, gender, and ethnicity. This resulted in 232 patients in each arm. The cohorts were then compared for the outcome of death at 5 years, as well as the development of metastases to lymph nodes, lung, bone, liver, and peritoneum (C79.51, C78.0, C77, C78.7, C79.89). Results: Patients who underwent chemoradiation had significantly higher mortality at five years than those that underwent cystectomy (38.4% vs 20.3%, RR 1.89, 95% CI (1.40,2.56), P value < 0.0001). Patients treated with chemoradiation were also six times more likely to develop metastatic disease to lymph nodes, lung, bone, liver, or peritoneum (31.0% vs 5.2%, RR 6, 95% CI (3.3,10.8), P value < 0.0001). Conclusions: Patients with stage II or III bladder cancer can be treated with either cystectomy or chemoradiotherapy. Both options are Category 1 recommendations of the National Comprehensive Cancer Network, with patient preference often a deciding factor. This study found that the development of metastatic disease and mortality may be more substantial than previously believed, suggesting that bladder cancer is a relatively chemoradiation resistant malignancy.