Abstract
BACKGROUND: Most cases of upper tract urothelial carcinoma (UTUC) exhibit recurrence within the first year following surgery. The time from surgery to recurrence significantly impacts cancer-specific survival. In this study, we analyzed patients with localized UTUC (pTis-3N0/xcM0) who experienced postoperative recurrence to identify an appropriate early recurrence time point and the associated risk factors. METHODS: From July 1988 to October 2022, we retrospectively analyzed 3435 localized UTUC patients after undergoing radical nephroureterectomy using Taiwan's UTUC Collaboration Group Database. Early recurrence time point was defined according to oncologic outcome. Variables including clinical and pathological characteristics were assessed in relation to early recurrence. A prediction model was constructed by factors associated with early recurrence and externally validated. RESULTS: Early recurrence time point in localized UTUC was determined at 9 months post-surgery, with patients experiencing early recurrence exhibiting worse overall and cancer specific survival. Diabetes mellitus, multifocality, lympho-vascular invasion, tumor necrosis and pathologic T stage were independent factors associated with early recurrence. The predictive model for early recurrence achieved an area under the curve (AUC) of 0.84 (95%CI: 0.82-0.86). External validation demonstrated that the model exhibited good discrimination (AUC: 0.76, 95%CI: 0.73-0.79), calibration (Brier score: 0.08) and clinical utility in a distinct cohort. CONCLUSIONS: This study identified the optimal time point for early recurrence and its associated risk factors. A prediction model for early recurrence was developed based on these factors and validated externally, demonstrating good generalizability. This clinical tool can facilitate early identification of high-risk patients, enabling targeted surveillance and timely intervention. Future studies should explore effective treatment strategies for preventing early recurrence.