The powerful genetic tool may help spare many early-stage lung cancer patients with less aggressive disease from unnecessary chemotherapy -- and all its unpleasant side effects, says researcher Ming Tsao, MD, professor of laboratory medicine and pathobiology at the University of Toronto. "Not all patients benefit from chemotherapy, and not all patients require chemotherapy after surgery."
"If validated, this genetic signature could potentially identify those patients who have aggressive cancer and who would benefit from chemotherapy and perhaps just as importantly, those patients not likely to benefit," he tells WebMD.
The findings are scheduled to be released at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago.
Gene Test Predicts Risk of Lung Cancer Recurrence
First, the researchers used a commercially available gene chip to analyze banked tumor tissue samples from patients who did not receive chemotherapy after surgery for non-small-cell lung cancer.
They were able to identify a set of 15 genes that discriminated between those at high risk and those at low risk of recurrence -- regardless of a patient's age, tumor stage, or other characteristics. Some of these genes are known to play important roles in cell growth and death, or regulate other genes involved in cancer.
"The 15-gene signature was able to classify patients into two groups with very different risks of recurrence: 31 patients with a very good prognosis and a very low risk of recurrence, and 31 patients with a very poor prognosis and a very high risk of recurrence," Tsao says.
The researchers then tried out the test on patients who did receive chemotherapy after surgery. They found that 67 patients classified at high risk of recurrence by the test did indeed benefit from the chemo; they were 67% less likely to die than if they didn't receive the anticancer drugs.
Sixty-six patients who were classified at low risk of recurrence, on the other hand, gained no benefit from chemotherapy, Tsao says.
Similar Test Available for Breast Cancer
Richard L. Schilsky, MD, president-elect of ASCO and professor of medicine at the University of Chicago, says this is "a very important and provocative paper."
Schilsky tells WebMD: "We know that chemo after surgery improves survival for patients with many common solid tumors, including breast, colorectal, and non-small cell lung cancer. But we also know that not every patient needs it; across the board, about 50% to 65% of people with solid tumors are cured by surgery alone. So what we would really like is some type of test that tells us who is at very high risk of recurrence and therefore who needs treatment, and that is exactly what this research is aiming to do."
Schilsky notes that a similar test, known as Oncotype DX, is already commercially available for women with some types of breast cancer. Researchers recently reported that the test has significantly cut down on the number of women who are unnecessarily undergoing chemotherapy after surgery to remove their breast tumors.
Alimta for Advanced Lung Cancer
Also at the meeting, researchers are scheduled to report that people with advanced non-small-cell lung cancer may benefit from taking the anticancer medication Alimta after finishing their regular course of chemotherapy.
In a study of 581 patients, cancer progressed in patients given placebo after just two months vs. four months for those on Alimta.
Also, there's also some suggestion that the additional treatment may extend lives, says Tudor Eliade Ciuleanu, MD, PhD, associate professor at the University of Medicine and Pharmacy Iuliu Hatieganu in Romania. His team is continuing to follow the patients to determine if it does improve survival rates.
"This is the first study to show that lung cancer patients can benefit from maintenance therapy. The fact that this approach significantly increases the amount of time that patients have before their cancer progresses, without increasing additional side effects, is particularly significant," he says.
Before being randomly assigned to Alimta or placebo, all the patients had completed a standard chemotherapy regimen.
Alimta is approved to treat non-small-cell lung cancers that progress despite standard chemotherapy.
The new findings suggest patients may benefit from receiving Alimta even before their tumors start to come back, says Schilsky. He was not involved with the work.
A total of 215,020 Americans will be newly diagnosed with lung cancer in 2008, and 161,840 will die of the disease, according to estimates by the American Cancer Society.
The researchers received funding from Eli Lilly, which makes Alimta.