I AM AN ONCOLOGIST. SO YOU CAN IMAGINE my delight that researchers have developed a non-invasive breath test that accurately detects colorectal cancer. Today, we explore how your breath – organic volatile compounds – may someday be a cancer screening tool.
I will be honest with you. I am sharing this piece in part because the new research is exciting.
But I am also sharing it to nudge you to have appropriate cancer screening.
Cancer: Early Detection Matters
Early detection matters when it comes to optimizing survival chances. No one wants cancer, but it is best to catch it early if you have it.
For example, in the U.S., the five-year survival rate of colorectal cancer is 91 percent when caught early. On the other hand, those with advanced disease have 16 percent odds.
Here are the numbers for the initial stage:
We have to do better. Only seven in 10 U.S. adults aged 50 to 75 are up-to-date with colorectal cancer screening. Are you?
A Breath Test to Diagnose Cancer
A breath test is a non-invasive, easy-to-complete test. I want to share the results of a new study using a breath test to find cancer.
In the Colorectal Breath Analysis (COBRA1) Study, a multi-institutional British team combined a breath test with machine learning to identify volatile organic compounds (VOCs) and clinical data.
This study aims to determine whether we can use a breath test to detect colorectal cancer and polyps early.
Investigators asked patients who presented for a planned colonoscopy (or scheduled to undergo elective resection of confirmed colorectal cancer) to provide a breath sample.
They then looked for volatile biomarkers to distinguish between colorectal cancer and benign (non-cancerous) conditions such as polyps. Researchers also included a healthy control group.
Study Results
The diagnostic model predicted colorectal cancer with good accuracy:
- Sensitivity 79 percent. This number means if cancer was present, the test accurately called it four out of the time.
- Specificity 86 percent. This number means that if no chance is present, the test accurately calls it 86 percent of the time.
- Negative predictive value 97 percent. This number means the test was good at saying there was no cancer when there wasn’t malignancy present.
Breath Test, Compared to Other Screening
When colorectal cancer was present, the innovative breath test could find it 79 percent of the time.
How does the breath test’s 79 percent sensitivity compare to other screening maneuvers?
Here are the estimates for colonoscopy, the FIT stool test, a blood test to find circulating tumor cells (CTCs), the fecal (stool) occult blood test, and a more advanced FIT test (FIT-DNA).
- The numbers assume screening from 50 to 75 years, including 100 percent adherence, complete follow-up without delay, and appropriate surveillance.
- The colonoscopy in the model is every ten years, CTC testing every five years, and stool tests (FIT, FOBT, FIT-DNA) are annual.
My Take — Breath – A Cancer Screening Tool
The U.S. Preventive Services Task Force states that individuals [at average risk] 45 to 75 should have colorectal cancer screening.
Individuals should choose if they want to have a screening between 76 and 85. If you are over 75, please discuss screening with your healthcare provider.
I am excited to see the number of screening options increase, especially in the non-invasive realm.
The breath-focused screening technique also targets esophagus, stomach, and pancreas cancers.
This non-invasive might be a great triage tool, as it appears to have a high negative predictive value — if the test says cancer is not present, there is a good chance it isn’t there.
Which Screening Test Should I Do?
Each screening approach has pros and cons. Talk to your primary healthcare provider about the benefits and risks of each test and how often to be tested.
Your choice of screening tool may hinge on several factors, including the following:
- Your personal preferences.
- Your medical condition.
- Your personal or family history of colorectal cancer or polyps.
- If you have a genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (Lynch syndrome).
- The probability that you will get the test.
- The resources available for testing and follow-up.
People at an increased risk of getting colorectal cancer should talk to their doctor about when to begin screening, which test is right for them, and how often to get tested.
The bottom line? Colorectal screening tools reduce the chances of dying of the disease.
Have you done colorectal screening? If yes, which test did you choose?
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Colorectal cancer screening sensitivity data from:
- Zauber A, Knudsen A, Rutter CM, et al. Evaluating the Benefits and Harms of Colorectal Cancer Screening Strategies: A Collaborative Modeling Approach. AHRQ Publication №14–05203-EF-2. Rockville, MD: Agency for Healthcare Research and Quality; October 2015.
- Knudsen AB, Zauber AG, Rutter CM, et al. Estimation of Benefits, Burden, and Harms of Colorectal Cancer Screening Strategies: Modeling Study for the U.S. Preventive Services Task Force. JAMA 2016; 315:2595.
Thank you for reading “Breath – A Cancer Screening Tool.” One more thing:
