The Impact of Tumor Size on Therapeutic Decision-Making for Upper Tract Urothelial Carcinoma: A Large-Scale Population Analysis.

PURPOSE: This study was designed to clarify the impact of tumor size on risk stratification in UTUC and to evaluate the feasibility and effectiveness of using 2 cm as a cutoff value for risk stratification.

METHODS

Using data from the Surveillance, Epidemiology, and End Results (SEER) database (2004-2021), we identified patients with nonmetastatic UTUC who underwent radical nephroureterectomy (RNU). Overall survival (OS) and cancer-specific survival (CSS) curves were generated by using the Kaplan-Meier method and compared with the log-rank test. Univariate and multivariate Cox proportional hazards regression models were used to identify predictors of OS and CSS. Univariate and multivariate logistic regression models were applied to assess predictors of adverse pathological features.

RESULTS

A total of 10,607 UTUC patients treated with RNU were included, comprising 7503 (70.7%) with renal pelvic UC and 3104 (29.3%) with ureteral UC. Tumor size ≥2.0 cm was independently associated with muscle-invasive disease (P < 0.001) and nonorgan-confined tumors (P < 0.001), but not with lymph node metastasis (P = 0.181). Tumor size ≥ 2.0 cm was independently associated with OS (P = 0.007) but not with CSS (P = 0.236). No significant difference in risk stratification ability was observed between a tumor size cutoff of 2.0 cm and those of 1.5 cm or 3.0 cm.

CONCLUSIONS

A 2-cm cutoff is a reasonable threshold for risk stratification in UTUC. Tumors larger than 2 cm are associated with a significantly increased risk of muscle layer invasion, extraorgan extension, and lymph node metastasis.