29 Sep, 2014
Spotting cancer early is key, but trying to do that — often when there are no symptoms — has been challenging.
Still, more and more evidence suggests that all cancers have a signature, or even a scent, that can be detected early. Now, researchers worldwide are testing simpler methods to spot the subtle signs of:
- Breast cancer
- Colorectal cancer
- Lung cancer
- Pancreatic cancer
- Oral cancer
- Other cancers
Some tests are already available.
“During the past couple of decades, scientists have learned a great deal about the cellular and molecular changes that distinguish cancers from normal tissues,” says Ted Gansler, MD. He’s the director of medical content at the American Cancer Society. “Most professionals who follow the field of cancer screening and diagnosis are excited about the implication of this … in eventually reducing cancer deaths.”
Breath Tests for Cancer
Your breath can reveal many clues about your health, and not simply whether you brushed recently. The air that you breathe out has hundreds of different chemicals, called volatile organic compounds (VOCs).
Many studies have shown that exhaled breath from people with lung and breast cancers has a distinctly different panel of “odors” or VOCs compared to the breath of people without such cancers.
Detailed lab experiments and a robust knowledge of cancer’s biochemistry helped fuel these findings. But some say you could also give a bit of credit to dogs.
Decades ago, there were a few word-of-mouth reports about dogs sniffing out cancer in their owners. Since then, “a growing number of scientific studies support the accuracy of dogs in detecting chemicals released by cancers,” Gansler says. Those include colon, breast, bladder, ovary, prostate, and lung cancer, among others.
Today, clinical trials are underway to find out if breath sensors and artificial noses based on dog-sniffing research can accurately detect certain lung cancers.
Peter Mazzone, MD, MPH, is director of the lung cancer program at Cleveland Clinic Respiratory Institute. He has studied breath and urine tests for lung cancer with encouraging results. “Our results have shown around 85% accuracy in distinguishing those with cancer in high-risk patients,” he says.
The tests are fairly simple and pose no risk, according to Mazzone. You just breathe out, and sensors in the equipment pick up your unique “breath print.” The odors in the breath sample are captured by the system and change colors when exposed to specific chemicals.
“Easy detection is the key,” says Hossein Borghaei, DO. He’s the chief of thoracic medical oncology at Fox Chase Cancer Center in Philadelphia, where a lung cancer breath test clinical trial is being done. “Exhaled breath collection is cheap and can be applied to a wide population relatively quickly and at low cost.”
A breath test may also help spot early breast cancer or help confirm an abnormal mammogram, according to research published online in the March 2014 issue of PLOS One.
Study co-author J. David Beatty, MD, says it’s possible that checking for VOCs in women without obvious symptoms “will help find breast cancer earlier and result in improved outcomes from treatments.” But he cautions that it’s too early to consider such testing as a replacement for mammograms. Beatty is the medical director of the clinical and bioinformatics program at the Swedish Cancer Institute in Seattle.