RESUMEN
OBJECTIVES: To prospectively investigate the role of a urinary mRNA biomarker (Xpert Test) after initial complete resection of T1 bladder cancer (BC) for the prediction of positive repeat biopsy for malignancy. METHODS: Patients who underwent TURBT for NMIBC between September 2018 and April 2020 were included. Patients with benign pathology, incomplete resection, concomitant CIS/upper tract urothelial tumor or muscle invasive BC, were excluded. 2 to 6 weeks after primary TURBT, voided urine sample was retrieved for Xpert analysis and patients were scheduled for repeat biopsy. The primary outcome was to determine the role of positive Xpert test to predict positive repeat biopsy for malignancy. RESULTS: During the study period, 254 patients met the study inclusion criteria of which 61 (24%) patients had recurrent NMIBC. Complete resection was censured by the presence of detrusor muscle in the specimen with documented T1 disease in all study participants. Xpert test was positive in 128 patients; of whom 85 (66.4%) showed positive repeat biopsy (HR=6.2, 95%CI=3.46-9.4, Pâ¯=â¯0.002). The sensitivity, specificity, positive and negative predictive values of Xpert test for repeat biopsy were 85.9% (95%CI: 82-89), 72.3% (95%CI: 68-76), 66.4% (95%CI: 62-71) and 88.9% (95%CI: 85-94), respectively. On median (range) follow up of 12(3-25) months, tumor recurrence was encountered in 84 (35%) patients. On multivariate Cox regression analysis, Xpert test was significantly associated with tumor recurrence (HR= 9.7, 95%CI=5-18, P <0.001). CONCLUSIONS: Positive Xpert test after primary complete resection of T1 BC is significantly associated with positive repeat biopsy for malignancy. In addition, Xpert test is an independent predictor of early tumor recurrence. Xpert test might be applied after initial complete resection of NMIBC to minimize unnecessary repeat biopsy with potential saving of healthcare costs and reduction in patient morbidity.
