image: MCED is able to detect multiple cancer types by analyzing cfDNAs, cfRNAs, circulating proteins and metabolites using liquid-based biopsy techniques and AI algorithms. The TOO results of an MCED test provide further guidance for subsequent clinical diagnosis and treatment. This new screening paradigm will eventually reduce cancer-specific mortality and be recommended for a broader population. (Created with BioRender.com).
Credit: ©Science China Press
This study is led by Prof. Wanqing Chen, Dr. Yongjie Xu, Dr. Changfa Xia (National Cancer Center, Chinese Academy of Medical Sciences and Peking Union Medical College, China), Dr. Sibo Zhu, Dr. Hui Yu, and Dr. Jing Liu (Shanghai Xiaohe Medical Laboratory Co., Ltd).
Current cancer screening methods are limited in scope. Techniques such as mammography, colonoscopy, and low-dose computed tomography (LDCT) cover only a few high-incidence cancer types and are often associated with high false-positive rates and invasive procedures, resulting in low patient adherence and limited overall effectiveness.
Liquid biopsy-based multi-cancer early detection (MCED) is regarded as a breakthrough in cancer screening and prevention. With advantages such as broad population and cancer-type coverage, minimal invasiveness, high patient compliance, and favorable health economic outcomes, MCED enables the detection of multiple cancers simultaneously—potentially with tissue-of-origin localization—through the analysis of biological markers such as cfDNA, cfRNA, and proteins collected from blood or other body fluids, enhanced by AI-driven algorithms.
Although several products have advanced their MCED platforms through technical development and into clinical phases, no MCED product has yet been approved for market release globally. This indicates that the translational pathway from laboratory research to clinical implementation still requires further validation through clinical trials and real-world evidence. From the standpoint of clinical efficacy, key metrics such as sensitivity, specificity, and TOO accuracy serve as crucial evidentiary endpoints and merit in-depth investigation. From the clinical utility perspective, "reduction in late-stage cancer incidence" is increasingly recognized as a feasible and credible surrogate endpoint for "reduction in cancer-specific mortality," given its shorter time span, lower cost, and higher practicality. Policymakers in public health must weigh a wide range of clinical evidence carefully when developing MCED-related screening guidelines.
At present, MCED should be viewed as a complementary, rather than replacement, strategy to existing cancer screening modalities. By expanding cancer type coverage and improving screening adherence, MCED offers potential to enable earlier diagnosis and treatment, thereby reducing healthcare costs and improving quality of life. Some studies suggest that if the per-test cost of MCED can be kept within an acceptable range, the technology could be cost-effective. With ongoing technological advancement, supportive policies, and reimbursement mechanisms, MCED may achieve broader adoption in the coming years and become a key component of comprehensive cancer control strategies.
Nevertheless, significant challenges remain. A critical question for both developers and regulators is how to balance surrogate endpoints—such as positive detection rate and patient adherence—with actual public health benefits. Another major challenge lies in detecting early-stage cancers, especially those with low cfDNA shedding or very small tumor burdens, which limits sensitivity. In addition, efforts must be made to minimize false positives, false negatives, and mislocalization errors that may lead to unnecessary interventions and increased patient anxiety. Finally, the unequal distribution of technical resources and high costs pose risks of health inequity, requiring context-specific implementation strategies.
Looking forward, MCED is expected to serve as a valuable supplement to traditional cancer screening approaches. It holds the potential to broaden population-level screening coverage and enhance cancer control. With continued progress in technical validation, cost control, and clinical evidence generation, MCED may gradually achieve standardized implementation and widespread use within global healthcare systems.
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