Micropapillary variant of upper tract urothelial carcinoma: a SEER-based propensity score–matched analysis of clinicopathological features and survival outcomes
摘要
To utilize a population-based database to compare the clinical-pathological characteristics and survival results of the micropapillary variant of upper urinary tract urothelial carcinoma (UTUC) with those of conventional papillary UTUC.
MethodsIn this retrospective cohort study, SEER data were used for patients diagnosed with upper urinary tract urothelial carcinoma (UTUC) between 2000 and 2022. After applying predefined exclusion criteria, a total of 10,096 patients were included in the study, comprising 10,037 with conventional papillary UTUC and 59 with the micropapillary variant of UTUC. Clinical and pathological characteristics and survival results were compared among the groups. Cancer-specific and overall survival was evaluated using Kaplan–Meier and Cox regression analyses. To reduce baseline imbalance, a 1:4 propensity score matching was performed using two separate models.
ResultsPatients with micropapillary variant UTUC had higher rates of high-grade tumors and advanced-stage disease than those with conventional papillary UTUC. In the unmatched cohort, cancer-specific survival was significantly worse in the micropapillary group, whereas overall survival did not differ significantly. In the matched analysis including stage and grade, no significant difference was observed in either outcome. However, when stage and grade were excluded from the matching model, cancer-specific survival remained significantly worse in the micropapillary group. In multivariable Cox analyses, micropapillary histology was not an independent predictor of survival.
ConclusionsMicropapillary UTUC is associated with higher grade, more advanced stage, and a more aggressive clinical presentation than conventional papillary UTUC. Although its association with survival was attenuated after matching or adjustment for stage and grade, these variables may represent part of the biological expression of the micropapillary subtype. Therefore, the independent and total prognostic effects of micropapillary histology cannot be clearly separated using registry-based observational data.