Identifying Novel Biomarkers Ready for Evaluation in Low-Prevalence Populations for the Early Detection of Upper Gastrointestinal Cancers: A Systematic Review
In 2018, there were over 2.1 million new cases of upper gastrointestinal (UGI) cancers (stomach, oesophagus, pancreas and biliary tract) diagnosed worldwide. However, detecting upper gastrointestinal (GI) cancers in primary care is challenging, as cancer symptoms are common, often non-specific, and most patients presenting with these symptoms will not have cancer. For cancers with non-specific symptom signatures, we need better biomarkers to support diagnostic assessment. This study conducted a systematic review to identify novel biomarkers for upper GI cancers which have been sufficiently validated to be ready for evaluation in low-prevalence populations. 149 eligible studies were identified, with a total of 431 biomarkers identified. Yet, only 35 biomarkers had been investigated in at least two studies, with reported outcomes for that marker for the same tumor type. Other reviews have investigated biomarkers used for early cancer detection however, few have considered the evidence in the context of future application of tests in low-prevalence populations, such as primary care. This review confirms that more research is required before we have sufficient evidence about biomarkers for upper GI cancers to warrant their adoption into clinical practice.