Readers Write: New blood tests developed for early cancer detection

The Island Now

CEO Helmy Eltoukhy, Guardant Health co-founder, said at the recent American Society of Clinical Oncology meeting “scientists aren’t far from creating blood tests that can be used to detect the earliest stages of cancer.”

This company, working with Astra-Zeneca, is developing blood tests to help identify cancer patients likely to respond well to treatment with selected oncology therapies.

Bits of cancer DNA can be found in a patient’s blood and give doctors clues about which treatments are most likely to work. So-called “liquid biopsy” tests, which can detect this tiny genetic material, are already nearly a standard of care for people with Stage III or IV cancer, a cancer that is far along in its growth, Eltoukhy told an interviewer at the ASCO meeting in Chicago.

Guardant’s CEO said his product has been used in 50 different types of cancer, but lung cancer is about 45 percent of the volume because the traditional tissue biopsy is the most difficult and has the highest failure rate.

The researchers also suspected that DNA evidence alone might not be enough to identify all cancers or the place in the body the cancer originated. Previous studies had shown that many very early tumors don’t release DNA into the bloodstream at detectable levels and cancers in different parts of the body can have the same growth-promoting mutations.

So, the researchers at Johns Hopkins then enrolled people diagnosed with one of eight cancer types: ovary, liver, stomach, pancreas, esophagus, colon, lung and breast. No study participants had undergone chemotherapy or shown evidence that their cancer had spread beyond the original site. The team also tested 812 healthy people with no known history of cancer. One of the blood tests they used is called CancerSEEK, a pioneering blood test, that will be developed by Thrive Earlier Detection, Inc.

Also, Thrive Earlier just announced its launching using a circulating tumor, DNA and protein testing method, that is currently being validated in a 10,000-person trial with Pennsylvania’s Geisinger Health System.

After performing all of the tests, the researchers found CancerSEEK was best at detecting Stage II or III cancers, primary tumors that haven’t metastasized but are getting large. However, the test still detected 43 percent of early Stage I cancer. The test almost never missed a case of ovarian or liver cancer but was not as good in picking up colorectal, lung, or breast cancer.

Eltoukhy said Guardant is currently testing to find targeted therapy options for patients with non-small-cell lung cancer or who are in Stage III or Stage IV or have metastatic carcinoma. This company has a goal of using its test in one million people over the next five years. This would be a dramatic accomplishment. It launched its first product called a liquid biopsy in 2014 and its tests have been given to 40,000 people, but the goal is not just to increase use but to collect data.

Dr. Francis Collins, director of the National Institutes of Health, in a blog issued in January, 2018, wrote that early detection usually offers the best chance to beat cancer. Unfortunately, many tumors aren’t caught until they’ve grown relatively large and spread to other parts of the body.  

In Conversation-Medical Press, Mel Ziman tells of a new blood test that could detect early-stage melanoma in lung cancer. The test can identify cancer DNA that was shed from tumors and track how well someone is responding to treatment faster and more accurately than other tests.  

Another company is working on a blood test to detect cancer in healthy people. The data from a pilot study is using its diagnostic before running through two much larger clinical trials. Results were presented at the ASCO meeting. Data thus far shows it can detect cancer in the blood with relatively few false positives and that it is fairly accurate at identifying where in the body the tumor was found. The ASCR abstract showed that the test is more likely to identify tumors if they are more deadly.

Scott Kopetz, an associate professor at MD Anderson Cancer Center, says liquid biopsies provide much greater resolution than was possible before. Disease could be detected in patients who were previously thought cured by surgery. It would be possible to see if a particular drug was helping a patient without waiting for months for a change on an imaging scan.

Researchers at Johns Hopkins University, Bert Vogelstein, Kenneth Kinzler, and Nikolas Papadopoulos, in an article published in “Science” last year, demonstrated greater than 99 percent specificity with varying sensitivities in different cancer types and stages.

Exact Sciences, a company working with the Mayo Clinic to discover the relevant biomarkers and their technology platforms, can extract trace amounts of most relevant DNA and use a combination of biomarker type to detect cancer and pre-cancer suites at the most treatable stages.

The Freenome company connects people with next generation cancer screening and diagnostic tests through the power of AI, or artificial intelligence. Testing using blood biopsies is now being done for heart attack risk, emotional and physical pain, and concussions.

However, with all of the positive cancer information above, one big worry with a cancer blood test is that it would lead to large numbers of patients being diagnosed with mild tumors that would be better off untreated.

Full disclosure: this article and the information it contains is not intended to provide any form of financial or stock investment suggestions or advice. I am a retired pharmacist, not a financial stock picker or financial adviser. While from time to time I may own a few shares of stock of some of the companies mentioned, don’t consider that an endorsement of the company and or its stock.

Bertram Drachtman

Great Neck

Share this Article