Abstract

Abstract Objectives To evaluate the clinical characteristics of oligometastatic disease (OMD) in metastatic urothelial carcinoma (mUC) with visceral metastases when classified into synchronous and metachronous metastases. Methods Of 957 cases of de novo mUC treated between 2008 and 2023, 374 with visceral metastases were analyzed. Cases were classified into OMD with up to three metastatic lesions and polymetastatic disease (PMD), and into synchronous and metachronous metastases. The clinical characteristics and overall survival (OS) for each group were analyzed. Results Overall, 196 (52.4%) had synchronous metastasis and 178 (47.6%) had metachronous metastasis. Median OS for synchronous metastases was significantly shorter than for metachronous metastases (12.1 months vs. 15.3 months, p = 0.011). Among the synchronous metastases, 48 (24.5%) were OMD and 148 (75.6%) were PMD. There was no significant difference in OS between the OMDs and PMDs (median 14.9 months vs. 11.7 months, p = 0.32), and only decreased albumin level was identified as a significant predictor of poor OS. Among the metachronous metastases, 64 (36.0%) were OMD and 114 (64.0%) were PMD. There was no significant difference in OS between the OMD and PMD (median 21.2 months vs. 15.0 months, p = 0.35), and no significant predictors of poor OS were identified. Conclusions For mUC with visceral metastases, the timing of metastasis appearance was associated with prognosis, with synchronous metastases being a poorer prognostic factor compared to metachronous metastases. There was no prognostic difference between OMD and PMD with visceral metastases when classified into synchronous or metachronous metastases.