Single Blood Test Could Detect Different Types of Cancer at Early Stages

Currently, reliable screening for only a few types of cancer is available, such as those affecting the breast, bowel, cervix (neck of the womb), and lung for individuals at high risk. While these screenings have been successful in reducing death rates from these cancers, they can sometimes lead to false positives and overdiagnosis. A groundbreaking single blood test, capable of detecting chemical signals from multiple types of cancer, may now be able to identify the disease in its early stages, making it easier to treat for nearly 50% of patients.

A study led by Queen Mary University of London (QMUL, London, UK) sought to determine if a multi-cancer early detection (MCED) test, administered annually or every two years, could detect cancer at an early stage and thereby improve patient outcomes. The study’s findings, published in BMJ Open, suggested that MCED tests have the potential to identify 31–49% of cancers at stages I-II that would otherwise be detected only at stages III-IV. The researchers used an existing disease progression model for various cancers to predict the effects of regular screening with an MCED test on cancer diagnosis times and patient survival under different screening schedules. The cancers included in the study span a wide range, including those of the anus, bladder, breast, cervix, bowel/rectum, esophagus, gallbladder, head and neck, kidney, liver/bile duct, lung, ovary, pancreas, prostate, sarcoma (soft tissues/bone), stomach, thyroid, uterus, and the blood cancers such as leukemia, lymphoma, melanoma, and myeloid neoplasms.

Image: A blood test for many cancers could potentially thwart progression to late stage in up to half of cases (Photo courtesy of Shutterstock)

The modeling results indicated that all MCED screening intervals showed better early-stage detection rates compared to standard care alone. The shift to earlier stages of diagnosis was particularly significant for tumors with faster growth, which tend to remain at stage I for 2 to 4 years before progressing. In contrast, tumors with fast, aggressive growth (progressing within 1 to 2 years from stage I) showed a smaller effect from early detection. The study found that annual MCED screening yielded more diagnoses and prevented more deaths within 5 years than screening every two years. In a scenario involving 392 individuals diagnosed annually with aggressive cancers that would lead to death within 5 years, biennial MCED screening could have prevented 54 (14%) deaths, while annual MCED screening could have prevented 84 (21%) deaths.

“When choosing how often to offer different type of cancer screening there is a balance to be made between preventing more cancer deaths and obtaining the greatest benefit for the costs and inconvenience of screening. Generally, the faster the cancer develops the more frequently one needs to screen,” said Professor Peter Sasieni, Professor of Cancer Epidemiology, Centre Co-Lead for the Centre for Cancer Screening, Prevention and Early Diagnosis, at QMUL. “We modelled what might be appropriate for a screening test that can detect all types of cancer. If screening works, even screening once every three years would prevent a substantial proportion of advanced stage cancers, but more frequent screening is needed to maximise the potential benefit. Depending on pricing, it seems likely that annual testing might deemed the most appropriate for blood-based multi-cancer screening.”