A larger detrusor wall thickness increases the risk of non muscle invasive bladder cancer recurrence and progression. Result from a multicenter observational study

BACKGROUND: Recent experimental study showed a higher incidence of bladder cancer in presence of bladder detrusor muscle thickening. The aim of this study is to assess whether a higher detrusor muscle thickness (DWT) may be a risk factor of recurrence of non-muscle invasive urothelial bladder cancer (NMIBC). METHODS: Men with histologically-confirmed diagnosis of NMIBC were prospectively enrolled in 4 centers between December 2015 and April 2017. DWT was measured by ultrasound and DWT>2.5 mm was used as threshold for detrusor muscle thickening. Patients underwent to adjuvant local treatment in according to their progression and recurrence risk computed by European Organization Research and Treatment of Cancer (EORTC) Score for NMIBC. Every three months cystoscopy and urinary cytology were used to detect disease recurrence and progression. The main clinic-pathological variables were compared between patients with DWT=2.5 mm and DWT>2.5 mm. RESULTS: One hundred patients (49.8%) with DWT >2.5 mm were significantly older, had larger and more tumors and experienced more prior NMIBC than 101 (50.2%) patients with a DWT=2.5 mm. Recurrence and progression disease occurred more often and briefly in patients with a detrusor muscle thickening. At univariate analysis, DWT>2.5 was a predictive risk factors of cancer recurrence and progression, respectively: OR 4.9 (95% CI: 2.5-9.5) P=0.001 and OR 2.21 (95% CI: 1.71-4.73), P=0.001. Enclosing DWT in EORTC risk calculator significantly increased by 3% and 1% recurrence and progression risk assessment, respectively. CONCLUSIONS: Detrusor muscle thickening may have a role in NMIBC course with a higher recurrence rate, however further confirmatory and elucidating studies are required.