Multitumor blood tests, also known as multicancer early detection (MCED) tests, have generated significant interest due to their potential to detect multiple cancer types concurrently using a single blood sample. However, their clinical utility and impact on patient outcomes remain areas of active investigation and debate.
Diagnostic performance
- Sensitivity and specificity: MCED tests have demonstrated varying levels of sensitivity and specificity. For instance, a study validating an MCED test reported a specificity of 99.5% and an overall sensitivity of 51.5%, which increased with cancer stage
- Cancer signal origin prediction: The same study reported an accuracy of 88.7% in predicting the cancer signal origin in true positive cases
Clinical utility
- Early detection: MCED tests have the potential to improve early cancer detection, including cancers that currently lack effective screening methods
- Diagnostic workup: A positive MCED test necessitates a broad diagnostic workup to confirm the location and type of underlying cancer, which can be a complex process
- Impact on mortality: The impact of MCED tests on cancer-specific and all-cause mortality is yet to be fully understood. Randomized clinical trials are needed to ascertain their effect on patient-centered outcomes
Challenges and uncertainties
- False positives and negatives: MCED tests can yield false positive and false negative results, which can lead to unnecessary diagnostic procedures or missed diagnoses
- Overdiagnosis and overtreatment: There is a risk of overdiagnosis and overtreatment, particularly of indolent diseases that may not have caused harm if left undetected
- Health disparities: The use of MCED tests could potentially alleviate or exacerbate existing health disparities, an ethical consideration that needs to be addressed
In conclusion, while multitumor blood tests hold promise for early cancer detection, their clinical utility and impact on patient outcomes are not yet fully established. Further research, including randomized clinical trials, is needed to evaluate their benefits, harms, and cost-effectiveness