Transforming cancer screening: the potential of multi-cancer early detection (MCED) technologies

Early cancer detection substantially improves the rate of patient survival; however, conventional screening methods are directed at single anatomical sites and focus primarily on a limited number of cancers, such as gastric, colorectal, lung, breast, and cervical cancer. Additionally, several cancers are inadequately screened, hindering early detection of 45.5% cases. In contrast, Multi-Cancer Early Detection (MCED) assays offer simultaneous screening of multiple cancers from a single liquid biopsy and identify molecular changes before symptom onset. These tests assess DNA mutations, abnormal DNA methylation patterns, fragmented DNA, and other tumor-derived biomarkers, indicating the presence of cancer and predicting its origin. Moreover, MCED assays concurrently detect multiple cancers without recommended screening protocols, potentially revolutionizing cancer screening and management. Large trials have reported promising results, achieving 50-95% sensitivity and 89-99% specificity for multiple cancer types. However, challenges, regarding improving accuracy, addressing ethical issues (e.g., psychosocial impact assessment), and integrating MCED into healthcare systems, must be addressed to achieve widespread adoption. Furthermore, prospective multi-institutional studies are crucial for demonstrating the clinical benefits in diverse populations. This review provides an overview of the principles, development status, and clinical significance of MCED tests, and discusses their potential and challenges.