A blood test for cancer detection at an early stage

A main problem in treating cancer is that often it is not detected at an early stage. In the earlier stages the tumour has not metastasized to further organs which makes it possible to remove the tumour surgically. When the tumour has not metastasized, this is the safest way to cure cancer. However, if the tumour has spread throughout the entire body, a surgical removal is not possible anymore. In these cases, chemotherapy has to be applied. Nowadays also new methods are developed which might be able to replace chemotherapy, such as cancer vaccines (http://stm.sciencemag.org/content/10/426/eaan4488) or nanorobots (https://www.nature.com/articles/nbt.4071).

Given the fact that chemotherapy comes with many side-effects and newer immunotherapies are still being tested and quite expensive, detecting a malicious tumour at an early stage and removing it surgically is the best treatment at the moment.
Furthermore, it is also not guaranteed that the current therapies are effective enough to kill the cancerous cells.
Therefore, it is so important to have a robust testing method which can detect different types of cancers. Current methods to identify cancers are for instance mammography and colonoscopy. However, a blood-based test has not been approved yet. When designing a cancer-detection blood test researchers, were faced with many challenges.

Source

Quite recently, a lab group at the Johns Hopkins Sidney Kimmel Cancer Center published a paper in which they described their blood-test CancerSEEK for detecting early cancers. Their blood-test is based on two components namely ctDNA (circulating tumour DNA) and protein biomarkers. This CancerSEEK was tested on about 1,000 patients with non-metastatic tumours. Those included tumours of the breast, colorectum, lung, ovary, liver, stomach, pancreas, esophagus.

Although the results were not perfect, they were still promising. Their test was able to detect 70% of the cancer types considered. Moreover, the specificity was quite high (< 99%) and in < 80% of patients, it was able to localize the cancer.
This blood-test still needs to be further developed. Nevertheless, it laid a solid foundation for the development of cancer detecting blood-tests which may contribute to a more efficient cancer treatment therapy.