Pathological characteristics and clinical course of bladder tumour developing after nephroureterectomy.

OBJECTIVES To determine the pathological features and clinical course of intravesical recurrence after nephroureterectomy (NU) for upper urinary tract (UUT) cancer. PATIENTS AND METHODS Among 325 patients undergoing NU with bladder cuff excision for UUT cancer, in this retrospective multi-institutional study we evaluated 113 who developed bladder tumour after NU. Excluding patients with (i) perioperative systemic chemotherapy or radiotherapy for UUT cancer; (ii) a history of previous or synchronous bladder cancer at the time of NU; (iii) distant metastasis at the time of NU; (iv) a follow-up of < 1 year after the initial bladder cancer recurrence; or (v) missing data, 74 patients were included in this study. We compared the pathology between UUT cancer and the first bladder cancer recurrence, using Fisher's exact test. Further intravesical recurrence and bladder cancer progression was analysed using the Kaplan-Meier method, with the log-rank test used to assess significance. A Cox proportional hazard model was used for multivariate analysis. RESULTS The grade of the first bladder cancer recurrence strongly correlated with that of the UUT tumour (P < 0.001) and the carcinoma in situ (CIS) lesion with the first bladder cancer recurrence correlated with high grade (grade 3) UUT tumour (P < 0.001). In all, 56 of the assessable 70 patients further developed intravesical recurrence at a median interval of 7 months after the first bladder cancer recurrence. There were no clinicopathological factors that predicted the second recurrence. Progression occurred in 14 patients, at a median interval of 25 months. A CIS lesion with the first bladder cancer recurrence was a risk factor for progression on multivariate analysis. CONCLUSIONS A large proportion of the patients who developed bladder tumour after NU had further intravesical recurrence, which indicated its refractory nature. Especially when a CIS lesion is detected in the initial intravesical recurrence, a careful follow-up is mandatory to detect bladder cancer progression.