Diagnostic accuracy of cystoscopic biopsy for tumour grade in outpatients with urothelial carcinoma of the bladder and the risk factors of upgrading

Objective: To assess the concordance of tumour grade in specimens obtained from diagnostic cystoscopic biopsy and transurethral resection of bladder tumour (TURBT) and explore the risk factors of upgrading. Methods: The medical records of 205 outpatients who underwent diagnostic cystoscopic biopsy before initial TURBT were retrospectively reviewed. Comparative analysis of the tumour grade of biopsy and operation specimens was performed. Tumour grade changing from low-grade to high-grade with or without variant histology was defined as upgrading. Logistic regression analyses were performed to identify the risk factors of upgrading. Results: For the 205 patients, the concordance of tumour grade between specimens obtained from biopsy and operation was 0.639. The concordance for patients who were preoperatively diagnosed with low-grade and high-grade was 0.504 and 0.912, respectively. Univariate and multivariate logistic regression analyses showed that older age, tumour multifocality, high neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and low lymphocyte-to-monocyte ratio (LMR) were significantly associated with upgrading (odds ratio ranging from 0.412 to 4.364). The area under the curve of the different multivariate models was improved from 0.752 to 0.821, and decision curve analysis demonstrated a high net benefit when NLR, LMR, and PLR were added. Conclusion: Diagnostic cystoscopic biopsy may not accurately represent the true grade of primary bladder cancer, especially for outpatients with low-grade bladder cancer. Moreover, older age, tumour multifocality, high NLR, PLR, and low LMR are risk factors of upgrading, and systemic inflammatory markers improve the predictive ability.