Home Medizin Nicht-invasiver Bluttest zeigt eine Sensitivität von 83 % bei der Erkennung von Darmkrebs und gibt Hoffnung auf eine frühzeitige Diagnose

Nicht-invasiver Bluttest zeigt eine Sensitivität von 83 % bei der Erkennung von Darmkrebs und gibt Hoffnung auf eine frühzeitige Diagnose

von NFI Redaktion

In a recent study published in The New England Journal of Medicine, a team of scientists from the United States and Canada evaluated the performance of a blood-based test method using cell-free DNA for screening for colorectal cancer.

Study: A cell-free blood-based DNA test for colorectal cancer screening. Image Source: Connect world/Shutterstock.comStudy: A cell-free blood-based DNA test for colorectal cancer screening. Image Source: Connect world/Shutterstock.com

Background

Colorectal cancer is one of the most common cancers in the adult population of the United States, with the second-highest mortality rate and the third-highest incidence rate.

Although the lifetime risk of developing the disease is 4%, overall survival depends on early detection of the cancer.

Individuals diagnosed with cancer in the localized early stage have a 5-year survival rate of 91%, while those with metastatic cancer have a 5-year survival rate of 14%.

Leading cancer experts and organizations like the US Preventive Services Task Force recommend asymptomatic screening to reduce the incidence and mortality associated with colorectal cancer.

Despite the various stool-based and direct visualization tests available for colorectal cancer screening, the adherence rate to regular asymptomatic screening remains at 59%.

Furthermore, a significant percentage of colorectal cancer-related mortality is attributed to individuals who do not undergo regular screening. These statistics underscore the need for a simple and easily applicable method for colorectal cancer screening to improve adherence to screening.

About the Study

In the current study, the scientists evaluated the performance of a blood-based test that examines colorectal cancer using cell-free DNA.

Their goal was to address the main factors responsible for the low adherence rate in colorectal cancer screening, including the pain and invasiveness of the test methods, the time required to perform the test, the embarrassment and discomfort associated with endoscopy, and the lack of proximity to test providers, among others.

Participants in the multicenter, observational, prospective study were recruited from over 200 locations, including endoscopy and primary care centers.

Individuals aged 45 to 84 were eligible to participate in the study if they underwent routine colonoscopy-based screening and had an average risk of colorectal cancer.

Individuals with inflammatory bowel disease, a genetic predisposition to colorectal cancer, or a family history of colorectal or cancer in the past were excluded from the study.

All participants provided a blood sample before colonoscopy. A colonoscopy, which included visualization and photographic documentation of the ileocecal valve or cecum junction, was considered complete unless visualization was hindered by a large mass or lesion.

The location and size of lesions identified by colonoscopy were recorded, and the resected lesions were processed for histopathological analysis.

The blood samples underwent cell-free DNA testing to detect genomic alterations, genetic fragmentation, and abnormal methylation patterns in cell-free DNA indicative of colorectal cancer.

The two primary outcomes of the study were the sensitivity and specificity for colorectal cancer and advanced neoplasia. The secondary outcome was the test’s sensitivity in detecting advanced precancerous lesions.

Results

The results showed that the blood-based cell-free DNA test had a sensitivity of 83% in detecting colorectal cancer, a specificity of 90% in detecting advanced neoplasia, and only a sensitivity of 13% in detecting advanced precancerous lesions. The test also had a false positive rate of 10% in detecting neoplasia.

Despite the large diversity of the study population in terms of race and ethnicity, the test’s performance showed no significant differences, indicating consistent performance across all subgroups. However, age was a factor that inversely influenced the test’s specificity, possibly due to age-specific cell-free DNA methylation signals.

The sensitivity for detecting colorectal cancer in this blood-based cell-free DNA test was higher than that of fecal immunochemical tests (67.3%) but lower than that of multitarget stool DNA tests (93.9%).

However, the test’s sensitivity in detecting advanced precancerous lesions compared to tests such as the methylated Septin9 test, fecal immunochemical test, and multitarget stool DNA test, was the lowest.

Additionally, the test’s sensitivity also varied depending on the clinical stage of colorectal cancer, with a sensitivity of 55% for stage I cancer and 81% for colorectal cancer in stages I to III.

Conclusions

In summary, the study found that a blood-based test for detecting colorectal cancer using cell-free DNA had a sensitivity of 83% in detecting colorectal cancer, higher than that of stool-based immunochemical tests but lower than that of stool-based DNA tests.

However, the test’s sensitivity in detecting advanced precancerous lesions was lower than any other method.

Although the blood-based test represents a quick, relatively painless, and non-invasive method for colorectal cancer screening, these results suggest that further research on larger study populations is needed to improve the test’s sensitivity and specificity.

Journal Reference:

  • Chung, DC, Gray, DM, 2., Singh, H., Issaka, RB, Raymond, VM, Eagle, C., Hu, S., Chudova, DI, Talasaz, A., Greenson, JK, Sinicrope, FA, Gupta, S. & Grady, WM (2024). A cell-free blood-based DNA test for colorectal cancer screening. The New England Journal of Medicine 390(11), 973–983. doi:https://doi.org/10.1056/NEJMoa2304714. https://www.nejm.org/doi/full/10.1056/NEJMoa2304714

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