A blood test to identify lung cancer in its early stages could potentially save millions of lives if initial results can be confirmed, researchers say.
French scientists on Monday announced preliminary results from a new lung cancer test at the annual congress of the European Society for Medical Oncology, a meeting of some 10,500 doctors, scientists, pharmaceutical representatives and non-governmental organizations.
The test distinguishes lung cancer from other lung diseases, such as emphysema.
People who smoke develop multiple changes in their genes; both those who get cancer and those who get other lung diseases often have the same type of cell degeneration. But at a certain point, people who develop cancer exhibit different changes at the molecular level.
"The point of this test is to catch patients at the turning point, before the cancer spreads," said Dr. Paris Kosmidis, director of oncology at Hygeia hospital in Athens, Greece, who was not connected to the study. "If we catch lung cancer early enough, we've proven in practice that we can cure it," said Kosmidis.
The new test works by detecting proteins produced by cancer cells in the blood. Cancer cells produce different types and amounts of proteins in the blood, giving them a unique protein profile. Researchers theorize that such protein signatures might be spotted long before the symptoms of lung cancer appear and before the disease would be detectable in X-rays giving patients the possibility of early treatment and thus strengthening their survival chances.
"The findings could help overcome a major problem with cancer diagnosis," said Dr. William Jacot, the study's principal author and a medical oncologist at Hopital Arnaud de Villeneuve, Montpellier, France.
Nearly 75 percent of patients diagnosed with lung cancer are caught only in the advanced stages of the disease, when the cancer has already spread to other parts of the body. The prognosis at this stage is usually poor, with a maximum of 16 percent of patients surviving for at least five years after diagnosis. But if lung cancer is identified early enough, patients can be essentially cured. Lung cancer is the most common type of cancer worldwide, with an average of two million patients diagnosed annually.
Jacot and colleagues analyzed serum samples from 170 patients (of which 147 had lung cancer and 23 had chronic lung disease), looking for the protein blueprint of cancer cells. Their test accurately identified lung cancer in nearly 90 percent of the specimens tested. "It's still not good enough to use as a screening tool, but it's better than conventional tumor markers," he said, adding that the test's methodology needs to be refined and confirmed in larger studies using greater numbers of healthy people, so as not to skew the results.
While experts guessed that the blood test might still be at least five to 10 years away from being an everyday medical reality, they said that its hypothesis, of testing for cancer through blood tests, is promising.
"If this can be confirmed, it would have an incredible impact," said Dr. Hans-Joachim Schmoll, director of hematology and oncology at Martin Luther University in Wittenberg, Germany, who had no ties to the study. "This could potentially revolutionize cancer care and save millions of people," he said. Schmoll said that the blood test could be performed routinely every few months in people at high risk of lung cancer, reports AP.
Similar blood tests to detect ovarian cancer are also under investigation, though this is the first test to target lung cancer. If the French approach to detecting lung cancer works, scientists might be able to adapt it to look for other types of cancer.
"We are still in the very early stages of this test, but if it works, we will have another tool to screen for lung cancer," said Jacot. "And that will make a big difference."