Squamous cell carcinoma of the upper urinary tract: clinical characteristics, treatment patterns, and survival outcomes in the National Cancer Database.

PURPOSE

We sought to investigate the disease characteristics, treatment patterns, and survival outcomes of upper urinary tract squamous cell carcinoma (UT-SCC) using the National Cancer Database (NCDB).

METHODS

The NCDB was queried for UT-SCC patients from 2004 to 2020. Patients with upper tract urothelial carcinoma (UTUC) were also identified for comparison with UT-SCC. Baseline characteristics were compared between UT-SCC and UTUC patients. Kaplan-Meier analysis assessed stage-based differences in median overall survival (mOS) between 1:4 propensity-matched cohorts of UT-SCC and UTUC patients. Predictors of mortality were assessed via multivariate cox regression.

RESULTS

644 cases of UT-SCC and 55,994 cases of UTUC were identified. Compared to UTUC, UT-SCC patients were more likely to have a higher TNM stage, lymphovascular invasion, and positive surgical margins. UT-SCC demonstrated a comparable mOS to UTUC for non-metastatic T1-T2 disease (74.84 vs. 106.38 months, p = 0.353) and metastatic disease (5.62 vs. 7.16 months, p = 0.058). However, UT-SCC carried a poorer prognosis for carcinoma in situ (45.14 vs. 69.32 months, p = 0.032) and non-metastatic T3-T4 disease (13.63 vs. 31.93 months, p < 0.001). Moreover, we found increasing T stage, metastatic disease, and positive surgical margins to be significant predictors of UT-SCC mortality. Lastly, we found that surgery does not confer a survival benefit over other management strategies for metastatic UT-SCC.

CONCLUSIONS

UT-SCC is a rare, aggressive malignancy that typically presents with a more advanced stage than UTUC. Surgical margin status may represent one of the most salient predictors of UT-SCC mortality. Further studies are needed to best define treatment strategy for this uncommon malignancy.