Impact of squamous differentiation on intravesical recurrence and prognosis of patients with upper tract urothelial carcinoma.

Background: The prognostic role of squamous differentiation in upper urinary tract urothelial carcinoma (UTUC) is still unclear. This article describes the impact of squamous differentiation on prognosis and intravesical recurrence of patients with primary UTUC treated with radical nephroureterectomy (RNU).

Methods: Totally, we retrieved (I) 669 histologically confirmed UTUC patients without histologic variants; (II) 101 UTUC patients with squamous differentiation in our institution, dating from April 2003 to April 2016. The clinical pathological characteristics and survival outcomes were compared between these two cohorts.

Results: In our study, 13% UTUC patients were detected with squamous differentiation. The mean age of all the patients examined was 66, of whom 70% were males. Squamous differentiation significantly associated with tumor stage, tumor grade and lymphovascular invasion. The Kaplan-Meier and Cox regression analyses showed that presence of squamous differentiation was correlated with shorter cancer specific survival of UTUC patients. The 5-year cancer specific survival rates were 47% for squamous differentiation-present patients and 63% for squamous differentiation-absent patients. UTUC patients with squamous differentiation showed a higher frequency of high-grade disease in advanced stage (pT2/pT3/pT4), while the discrepancy was not shown in early stage (pTa/pT1). Intravesical recurrence was observed in 27% patients. We found that intravesical recurrence had little impact on the cancer specific survival of squamous differentiation-present patients, yet it tended to decrease cancer specific survival among squamous differentiation-absent patients.

Conclusions: The presence of squamous differentiation in UTUC patients was a vital prognostic factor for cancer specific survival and correlated with intravesical recurrence after receiving RNU.