Exponential Tech: DNA testing in cancer screening (Part 2)
In last week’s post, we cruised through a primer on exponential technologies and how it can disrupt business and life as we know it. Moving on, this week we’ll attempt to understand how this applies to cancer screening in healthcare. We’ll do so from the lens of gastroenterology (GI).
Here’s what you’ll take away from this article:
• Present DNA testing methods of colon cancer screening (stool DNA testing)
• Upcoming DNA testing methods such as liquid biopsy (using a blood draw to detect not one but many types of cancers)
• Implications of exponential technologies in cancer screening
Colorectal cancer screening 101
For those of us in the GI world, colonoscopy is not new. Using the procedure, a gastroenterologist examines the colon and rectum for abnormalities. It is a key colorectal cancer (CRC) screening method and helps in detecting or removing small polyps in the colon. Larger polyps or tumours need a biopsy and further tests.
Colonoscopy is the gold standard in CRC screening. It detects and removes precancerous polyps well before they become malignant. If you test negative, you may not need to test yourself for the next 10 years.
Almost all insurances in the US cover this procedure. The cost of a colonoscopy could vary from $500 to $3,000 depending on it happens. It contributes to a significant portion of a gastroenterologist’s income. As you’ll soon find out, this revenue stream is at risk.
Colonoscopies have certain downsides. It’s invasive and inconvenient. An endoscopist inserts a scope (5-6ft narrow tube with a camera at the end) through the anus to examine the colon. The procedure requires sedation and a bowel prep.
Exponential Tech makes its way into cancer screening
The gastroenterology circuit is buzzing with newer alternate CRC screening methods. Though not as reliable a screening tool as colonoscopy is, these methods may pick up momentum soon. As you know from my previous article, exponential technologies scale up quickly after a point.
Extremely well funded startups and established players are working on stool DNA testing and liquid biopsy. These are not small forces.
Stool DNA testing
There are “old-fashioned” GI stool tests, fecal immunochemical tests (labeled FIT) or the guaic-based fecal occult blood tests (gFOBT). These detect blood in stools.
With DNA testing of stool, however, you check for not just microscopic blood but also altered DNA. Cologuard (a product from Exact Sciences) leads in this testing method. It was approved by FDA in 2014. The company sends a kit home. You can leave it at the doorstep for UPS to pickup! There are no trips to doctors or scopes poking around the posterior. Completely contactless – it seems to have a new upside in COVID times.
Cologuard vs. Colonoscopy
► Colonoscopy detects 95% of CRC and advanced precancerous polyps. If tested negative, you don’t need another test for the next decade.
► Cologuard has a 92% sensitivity rate and a 87% specificity rate overall, in a clinical study of 10,000 patients aged between 50-84 years at an average risk of CRC. False positives and false negative results can occur, which is still a high risk to patients. This indicates that once you have your readings, you still need to consult with your provider. In case the result is positive, diagnostic colonoscopy will follow. If negative, you will have to screen again in three years because the test is unable to detect high risk precancerous polyps definitively.
Cologuard has its benefits as a more convenient and comfortable screening method. The Cologuard kit costs US$ 649 and it takes two weeks to get the test results. Medicare and most of the insurances in the US cover it.
Cologuard has covered ample ground since it got FDA approval in 2014. More than 3.5 million people have been screened for colorectal cancer. It has captured less than 6% of the large addressable market of people over 50 years old. It’s long term goal is to reach 40% of the market.
Cologuard has competition. Liquid biopsy is trying to detect not one, but many cancers
This is a test done on a sample of blood. It looks for cancer cells from a tumor that are circulating in the blood or for proteins in the blood due to the response of the immune system to the cancer. This will help in detecting cancer at an early stage.
Freenome, Cellmax, Grail, Thrive and Guardant Health are some of the players using a blood draw for their CRC screening tests.
► Freenome. Set up in 2014, the company has received a total funding of $237.6 million. It uses molecular biology and machine learning to detect cancer. According to the company, they are pioneering the Multiomics platform that decodes cell free biomarker patterns to detect cancer at its earliest stages. It analyzes a blood sample not just for DNA shed by cancer cells but also for proteins. Any of the biological molecules Freenome detects could originate in tumor cells, or could come from the person’s immune system responding to the onset of cancer. Their focus is on colorectal cancer and the final study for FDA approval is underway.
► GRAIL. Founded in 2015, this startup also working in the diagnostics space has raised $2 billion for its technology that screens for multiple cancers. It received the FDA Breakthrough Device Designation status in May 2019. The Pathfinder Study initiated in early 2020 is evaluating the implementation of GRAIL’s multi-cancer early detection test in clinical practice.
Using a single blood draw, GRAIL’s still-in-development test can detect more than 50 cancer types across all stages. It has very low false-positive rate of less than 1%.
► Thrive Earlier Detection. The startup spun out of John Hopkins in May 2019. It’s backed by $110 million in venture funding. This is another company looking at multiple cancer screens through a liquid biopsy test.
► Cellmax and Guardant Health.These are other players betting on liquid biopsy with their cancer screening tests pending FDA approval. Guardant is a public company that’s frequently loved by Wall Street.
Liquid biopsy = autonomous cars?
Are these new screening methods like the autonomous cars we analysed last week? They may still be evolving in performance now, but, given the efforts going into product enhancement and cost reduction, they may emerge as reliable screening tools in future. Will the power of exponentials start playing out in CRC screening too?
Liquid biopsy for early cancer detection is still years away from being a reliable screening tool. Its noninvasive nature, quick turnaround times, low cost, real time monitoring etc. makes it an attractive option. However, the true power of this will unleash when the sensitivity and specificity of these tests improve as does our understanding of the biology of tumours and what can be found in the blood. Experts state it is still a few years away from effective implementation.
But wait…what about colonoscopy for screening?
Payers, patients, and physicians – all have a role to play in the choice of the screening tool.
In today’s consumer-driven healthcare, the best test for colorectal cancer screening is the one that the patients demands. A colonoscopy may be a gold standard but a patient may be unwilling to undergo the procedure.
Cologuard also invests heavily in TV advertising that influences patient demand.
Primary care doctors are now more willing to prescribe such noninvasive screening tools to cater to patient requests. As more DNA testing occurs, companies like Exact Sciences will get more data on DNA of cancers. With more data, sensitivity and specificity will improve.
Meanwhile, payers are continuing to cut reimbursements of screening colonoscopy.
The technology that we use for colorectal cancer screening will continue to evolve. The demand for less invasive, cheaper tests with faster turn-around times will continue to rise.
As with the rest of the healthcare industry, gastroenterology is bracing itself for massive change. The underlying reason for that change is exponential technologies in action.
Originally published on LinkedIn, by Suzette Sugathan, Director, NextServices
Image Credit: Pixabay