Developing biomarkers for improved diagnosis and treatment outcome monitoring of bladder cancer

Importance of the field: A non-invasive marker for the follow-up and diagnosis of bladder cancer is highly needed. Several markers have been studied with regard to sensitivity and specificity in detecting bladder cancer. Comparison of studies is complicated by limited data on tumor characteristics and treatment details. Many studies do not differentiate between primary and recurrent tumors, nor is the performance of the studied marker assessed separately in superficial and invasive or high-versus low-grade tumors. Areas covered in this review: The field of bladder cancer biomarker research from the past 15 years. What the reader gain: A summary of the current field of bladder biomarker research with concluding remarks on some specific challenges in developing biomarkers for improved diagnosis and monitoring the disease. Take home message: In general, the best new markers give higher sensitivity than urinary cytology, but specificity is usually lower. By using new markers, the intervals between follow-up cystoscopies can be increased and the detection of relapse can be improved. But to date no non-invasive biomarker has proven to be sensitive and specific enough available to replace cystoscopy, neither in the diagnosis nor in the follow-up of bladder cancer. However, new marker combinations and algorithms for risk assessment hold promise for the future.