Recurrence factors in patients with Keratinizing squamous metaplasia of the bladder after surgical management: a single-center retrospective study

BACKGROUND: Keratinizing squamous metaplasia (KSM) is a clinically heterogeneous disease that lacks research that provide definitive recurrent risk factors. Therefore, we identified the recurrence factors in patients with KSM of the bladder after transurethral resection (TUR). We also attempted to investigate the association between KSM and bladder cancer. METHODS: Clinical information of 257 patients diagnosed with KSM who underwent TUR in Xiangya Hospital from January 2010 to November 2018 were retrospectively collected. Clinical information was available for follow-up of 223 patients. To determine the risk factors for recurrence, we conducted univariate and multivariate cox regression analysis respectively. To explore the association between KSM and bladder cancer, we used clinical follow-up data. RESULTS: The median follow-up time is 49 (IQR, 12–121) months. Five-year recurrence-free rate (RFR) and 1-year RFR were 86.1% and 91.9%, respectively. Thirty-one patients (13.9%) relapsed of KSM after a median follow-up of 49 months (range, 12–121 months), and none of them developed subsequent bladder cancer. Univariate Cox analysis indicated that urinary tract infection [hazard ratio (HR) =2.111; 95% confidence interval (CI): 1.043–4.271; P=0.038], and atypical urothelial hyperplasia of the bladder (HR =4.191; 95% CI: 2.006–8.756; P<0.001) were significant recurrence factors. Multivariate Cox analysis suggested that atypical urothelial hyperplasia of the bladder (HR =3.506; 95% CI: 1.663–7.392; P=0.001) was the independent risk factor for postoperative recurrence of KSM. CONCLUSIONS: The recurrence rate in patients with KSM was about 13.9%, and atypical urothelial hyperplasia of the bladder was the independent risk factor in patients with KSM recurrence. In cases with bladder atypical urothelial hyperplasia, close follow-ups are necessary. Also, we demonstrated that KSM did not increase the subsequent risk of bladder cancer.