BACKGROUNDMultiple recurrences are common in non-muscle invasive bladder cancer, but the risk of multiple recurrences has not been fully described. Identifying patients at high risk of multiple recurrences will help to select an optimal therapeutic strategy and to improve prognosis. This study was conducted to identify the risk factors for multiple recurrences of non-muscle invasive bladder cancer.

METHODSWe reviewed the clinical data of all patients with non-muscle invasive bladder cancer in our hospital between January 2003 and February 2010. Patients with at least one recurrence were included. Multivariate analysis was performed for theorized risk factors (age, gender, tumor stage, grade, size, location, number of lesions, adjuvant intra-vesical chemotherapy after transurethral resection, and recurrence-free survival after each resection) to clarify risk factors for multiple recurrences of non-muscle invasive bladder cancer.

RESULTSOf the 278 patients with non-muscle invasive bladder cancer, 84 were with at least one recurrence and a total of 222 recurrences among them were followed up for 6 - 70 months (mean, 36.1 months). Recurrence-free survival after initial resection predicted the overall frequency of bladder cancer recurrence (risk ratio (RR) = 37.83, 95% confidence interval (CI) = 3.45 - 396.13, P = 0.001) and second recurrence (RR = 6.15, 95%CI = 1.28 - 29.57, P = 0.023). Similarly, recurrence-free survival after a second resection was the only significant risk factor for third recurrence (RR = 31.08, 95%CI = 2.53 - 381.47, P = 0.007). Moreover, recurrence-free survival after initial resection was the only significant factor to predict later progression to muscle invasive bladder cancer (RR = 8.62, 95%CI = 1.47 - 58.34, P = 0.001).

CONCLUSIONSRecurrence-free survival after resection is an independent predictor of multiple recurrences of non-muscle invasive bladder cancer. The shorter the period between resection and recurrence is, the higher the risk of multiple recurrences.