Can a yearly blood test find cancer as long as it’s curable? – Orange County Registry
Despite decades of efforts to fight cancer, screening tests are only available for five types of the disease, accounting for less than a third of all cases.
What if a single test with a single vial of blood could indicate dozens of cancers?
Innovations in genetics and computational technology that enable the detection of tiny fragments of genetic material shed from cancer cells with a “liquid biopsy,” or blood draw, are opening a new front in this fight.
“State-of-the-art techniques serve as a window to detect cancer early and get an idea of where the cancer is coming from,” said Dr. Ash Alizadeh, who directs the Cancer Genomics Program at Stanford Cancer Institute.
While the test is promising, there are also dangers. For example, according to Alizadeh and other experts at the recent Precision Medicine World Conference in Santa Clara, there is still no evidence that early detection of bad news actually extends life. And the test could do harm, they add, when people are being treated for cancers that otherwise would never have bothered them.
One company is already marketing its blood test, and more tests are in the pipeline. As part of President Joe Biden’s Cancer Moonshot, the National Cancer Institute plans to evaluate the value of such testing. It will conduct a four-year, $75 million study involving 24,000 people. Based on these results, the study could be expanded to 225,000 volunteers.
There are currently no screening tests for deadly cancers of the pancreas, ovaries, stomach, and other organs. Screening tests are only available for breast, cervical, colon and lung cancer, with prostate screening recommended on an individual basis. A different test is required for each type of cancer.
Current forms of cancer screening look for abnormal cells or solid clumps of tissue. Breast and lung cancer, for example, are detected with X-rays. Cervical cancer is found by removing cells. Screening for colon cancer uses a colonoscopy or stool test to look for polyps. When testing for prostate cancer, doctors look for clumps, or elevated protein levels.
The vision behind liquid biopsy, a field called multi-cancer screening, is to detect many cancers simultaneously at earlier stages when there is a better chance of successful treatment — and to integrate this test into routine medical care.
The concept is based on a discovery scientists made in the 1940s: when cells grow old and die, they release their genetic material into the bloodstream. Cancer cells behave the same way.
Taking a blood sample is easy, inexpensive and non-invasive – especially when compared to screening tests such as mammograms, colonoscopies or CT scans. But until recently there was a technical hurdle: it was almost impossible to distinguish the tiny number of cancer clues from the abundant healthy DNA that also circulates in the blood.
“It’s a needle-in-a-haystack problem,” Alizadeh said.
Two technological advances are changing the landscape. The first is genomics. Cheaper, faster and better gene sequencing tools can reveal the unique molecular properties of the DNA shed by tumor cells into the blood.
An approach called high-throughput gene sequencing “can sequence millions and billions of DNA molecules in a single sample so we can look for mutant molecules,” said Dr. Maximilian Diehn, a radiation oncologist at Stanford Medicine who specializes in treating lung cancer.
The second is advances in computer science, called bioinformatics. “When you have millions and billions of data points,” Diehn said, “you have to think: How do you interpret that?”
It is not necessary to find an actual cancer cell. Rather, scientists are looking for signs called “biomarkers.” The most common biomarker is called methylation, a sign that the DNA has been altered. They can also look for specific mutations or signs of extra or missing chromosomes, called aneuploidy. Or they could be looking for ominous proteins. New research from UC Santa Cruz biomolecular engineer Daniel Kim shows that certain types of RNA could also be indicative of cancer.
Detecting signs of cancer with a blood test is just a first step. Ideally, the genetic analysis would also reveal the carcinogenic organ.
Although an estimated 20 companies and academic labs are working on this new form of cancer detection, two companies have attracted attention because they have raised huge sums of money and are the scientific heavyweights doing research or sitting on their advisory boards.
Leading the way is biotech GRAIL, headquartered in Menlo Park, which is already offering its $949 prescription test to people over age 50 and others at increased risk of cancer. Its technology was developed by Dr. Richard Klausner, former director of the National Cancer Institute.
A Wisconsin-based company called Exact Sciences is completing development of a test that looks for not one, but four different biomarkers. Its liver cancer detection tool, developed by an elite team of scientists at Johns Hopkins Medical Center, has already received federal status as a “breakthrough device” and received an expedited review process.
Liquid biopsies are already being used to guide treatment for people with confirmed cancer. They help monitor the spread of cancer to other parts of the body; identify the genetic changes or mutations of a tumor; determine which drug treatments are most appropriate for particular patients; and show if treatments are working.
However, the use of the test for cancer screening faces ethical, practical and economic challenges. That’s because the test hasn’t yet been proven to improve patient outcomes. Experts fear some people could be told they have a “cancer signal” – prompting fear and further testing – only to be later told it was a false positive.
“The problem is that you can overstate things that never affect the person’s health,” said Kathryn Phillips, professor of health economics and health research at UC San Francisco. “Often it has an impact on the quality of life.”
Given these concerns, the tests haven’t yet passed the decision-makers who set payment policies for Medicare and other insurers.
According to an analysis by H. Gilbert Welch of Brigham and Women’s Hospital in Boston, if offered to the country’s 60 million Medicare beneficiaries annually, the tests would cost about $60 billion a year. That would mean a 7% increase in Medicare spending, which would be passed on to taxpayers in the form of higher premiums.
“We have to be good stewards of those dollars and not immediately give the green light to authorize these tests that could bankrupt Medicare,” Alizadeh said. “The tools need to be sharper and the results more tangible so we can bring them to hundreds of millions of Americans.”
https://www.ocregister.com/2023/02/08/can-an-annual-blood-test-find-cancer-while-its-curable/ Can a yearly blood test find cancer as long as it’s curable? – Orange County Registry