Cedars-Sinai Blog

New Breath Test Could Detect Cancer

What if a simple breath test could save lives by discovering cancer at an early stage?

That question has motivated research groups from around the world to analyze exhaled breath to find a "chemical signature" for for gastric and esophageal cancer, which claim over 700,000 lives worldwide each year. The early stages of these cancer types either cause no symptoms or can easily be mistaken for less serious ailments.

But recently, a team from Imperial College London and the Karolinska Institutet in Sweden announced that the breath test the team administered could correctly identify cancer in about 80% of their patients with stomach tumors.

"There has been a lot of work in this area for several years, and it really looks quite promising," said Dr. Joshua Ellenhorn, a surgical oncologist at the Cedars-Sinai Samuel Oschin Comprehensive Cancer Institute. "Right now, the only screening test for gastric cancer is an endoscopy, which is expensive and invasive."

"But with the new breath test, you can pinpoint the patients that you want to have an endoscopy by going through a large population and first doing a relatively inexpensive breath test."

Gastric Cancer Causes and Clues

Gastric or stomach cancer is almost always caused by the chronic presence of bacteria called Helicobacter pylori. The bacteria first leads to infection and inflammation. There is already a breath test for the bacteria, but it detects only the bacteria—not cancer.

Dr. Sheraz Markar, a clinical trials fellow at Imperial College, explains how the tumors themselves can now be discovered: "Because cancer cells are different to healthy ones, they produce a different mixture of chemicals. This study suggests that we may be able detect these differences and use a breath test to indicate which patients are likely to have cancer of the esophagus and stomach, and which do not."

"With a screening test like this, it may push gastric cancers up to a much earlier diagnosis where an outpatient endoscopic procedure can cure the cancer."

Researchers determined the specific chemical combination by testing them against the breath samples of over 300 people who had undergone an endoscopy to investigate upper digestive tract issues.

Improving the Surgical Option

Many gastric cancer patients can't be operated on because their tumors have progressed too far. Chemotherapy may have benefits, but it isn't curative. Surgeons like Cedars-Sinai's Dr. Ellenhorn are excited by the prospect of a screening test that could identify patients who haven't yet had metastases or have a tumor limited to the stomach that can be surgically removed.

"Even better," he says, "finding that there are only very superficial tumors in the stomach that are amenable to what's called endoscopic mucosal resections. That's when an endoscope basically peels the surface of the inside of the stomach where there's a very early tumor."

"With a screening test like this, it may push gastric cancers up to a much earlier diagnosis where an outpatient endoscopic procedure can cure the cancer."

The chemical signature breath test currently doesn't have government approval in the US or elsewhere. But the recent studies are very encouraging, and there are efforts to develop similar tests for bowel and pancreatic cancer. Meanwhile, there are unique populations that would almost certainly be helped by the new cancer screening.

Gastric Cancer Worldwide

Countries such as Korea, Japan, and China have more gastric cancer diagnoses than the United States. There are also populations in South America with high rates of the disease.

"In Chile, for instance, it's very high," explains Dr. Ellenhorn. "We don't really know why it's more prevalent in those other countries. A large part is Helicobacter bacteria. But it could be that there are genetic factors that combine with the H. pylori; not everybody who gets infections develops gastric cancer."

Nonetheless, there are certain population groups in the United States for whom the disease is more common. People born in Korea and neighboring Asian countries who have moved to the US would benefit from improved gastric cancer screening.

Those who have already been tested and are positive for Helicobacter pylori or who have had prior gastric surgery are also good candidates for the new breath test.