A simple blood test may soon detect cancer

One of cancer’s most nefarious traits is how elusive it can be. Often times, years pass before any sort of symptoms signifying the presence of cancer develops. Even then, these symptoms may present as simply fatigue or shortness of breath—signs that may be written off as something else.

There are hundreds of different types of cancer, all of which can present in unique ways. This makes it difficult to diagnose the type of cancer you have.

In general, blood tests cannot detect whether or not a person has cancer, with the exception of leukemia—a form of blood cancer. However, this may soon change, as new research into a single blood test to detect tumor DNA has recently proven to hold much promise.

Looking more closely at our genome

While studies are still in the early phases, researchers have been able to pinpoint at least one genetic change that can be observed on a simple blood test. This innovative approach uses high-intensity sequencing to detect cancer from circulating tumor DNA in the bloodstream, essentially detecting cancer early.

The process involves scanning a very broad area of the genome—our genes and chromosomes. While this type of testing has existed before, this high-intensity approach is able to yield 100 times more data with higher accuracy.

“Our findings show that high-intensity circulating tumor DNA sequencing is possible and may provide invaluable information for clinical decision-making, potentially without any need for tumor tissue samples. This study is also an important step in the process of developing blood tests for early detection of cancer,” said lead study author Pedram Razavi, a medical oncologist and instructor in medicine at Memorial Sloan-Kettering Cancer Center (MSK) in New York, NY.

A simple blood test to detect cancer

Studies testing this new procedure involved collecting blood samples from 124 patients with metastatic breast cancer, non-small cell lung cancer, or prostate cancer. Detailed genetic information was then sequenced using a combined analysis of cell-free DNA and white blood cell DNA for each blood sample looking for tumor DNA.

This can be difficult in itself, as tumors may have various genetic changes. These changes can be different in different parts of the same tumor as well as in different sites where the tumor spreads in the body.

The researchers found that in 89 percent of patients, at least one genetic change was detected. Overall, 864 genetic changes in tissue samples across all three tumor types were detected, 73 percent of which were detected in the blood.

While not completely foolproof, this new form of cancer detection is a giant leap forward. To be able to detect cancer without information from the actual tumor tissue itself is an amazing accomplishment. As further research is conducted with high-intensity sequencing, the development of future tests for the early detection of cancer is inevitable.