Point-of-Care Diagnosis of Bladder Cancer With Vibrational Spectroscopy: A Systematic Review

Abstract

IntroductionVibrational spectroscopy (VS) is a new and rapidly evolving technology in cancer diagnostics. Originating from analytical chemistry, VS evaluates vibrations of nuclei to produce a unique “biological fingerprint.” While multiple studies have been published on this technology and physician awareness has increased, no systematic review has evaluated the role of VS in bladder cancer (BCa) tissue diagnosis.MethodsTo conduct this systematic review, we searched the MEDLINE, Embase, and Cochrane databases for studies that used Raman spectroscopy (RS), surface-enhanced RS (SERS), infrared spectroscopy (IR) or near-infrared spectroscopy (NIRS) to analyze human BCa specimens. Studies using animal tissue or liquid biopsies were excluded. We synthesized the evidence by comparing modalities, study design, data analysis techniques, and diagnostic accuracy. The quality of evidence was evaluated by the QUADAS-2 tool.ResultsOut of 362 results, 20 studies met our inclusion criteria. There has been growing interest in VS use in BCa, with 50% of the studies published in the past 5 years. RS was the most commonly used modality (65%), followed by IR (20%) and SERS (10%). Only one study compared RS to IR (5%). The mean sample size was 44 patients (range, 6–214). To date, there have been only 2 in vivo studies, with the remaining ex vivo studies performed with large variation in tissue preparation, data analysis, and reporting. Advancements in fiber optic probes and machine-learning data analysis techniques, and increased computational power have improved diagnostic accuracy up to 98% sensitivity and 100% specificity.ConclusionsVS shows high potential for BCa diagnosis, but there is a need for uniform reporting methods and studies with adequate sample sizes to validate the models. RS has shown promising results, with ongoing improvements in fiber optic probes allowing its integration into conventional cystoscopes. While no single VS modality has proven to be perfect, a multimodal approach is likely required to establish its value in clinical practice.