Screen May Detect High-Risk Lung Cancer
NEW YORK (Reuters Health) - Michigan scientists have developed a method of identifying which patients with early-stage lung cancer might benefit most from aggressive treatment.
Though the screening, which looks for genetic markers of aggressive cancer in tumor cells, is not yet ready for widespread use, the analysis eventually may help patients with high-risk cancers live longer, according to researcher Dr. David G. Beer.
Lung cancer is the number-one cause of cancer deaths in industrialized countries. Most people with so-called non-small-cell lung cancer are not diagnosed until the cancer is already in an advanced stage. Just 8% to 10% of people with this type of lung cancer are still alive 10 years after diagnosis.
Even when lung cancer is detected early and is surgically removed, the cancer will return within 5 years in 35% to 50% of patients.
Unfortunately, it is not currently possible to identify high-risk patients who would be most likely to benefit from additional therapy besides surgery.
That may soon change, according to findings published in the advance online edition of the journal Nature Medicine. Using technology called microarrays, which make it possible to view thousands of genes at once on a single chip, researchers at the University of Michigan at Ann Arbor analyzed tumor samples from 86 patients with early- or late-stage adenocarcinoma, the most common type of non-small-cell lung cancer. Based on this analysis, Beer and colleagues compiled a list of the 50 genesmost associated with patient survival.
From that list, the researchers developed a "risk profile" to classify the aggressiveness of lung tumors. When Beer's team applied these risk profiles to a sample of early-stage lung cancers from another study, they were able to distinguish between low- and high-risk cancers.
"The strategy used in our study involving the developing of a risk index of survival-related gene expression not only provides a means to identify genes involved in aggressive tumor behavior and potentially new targets for therapy, but also allows for independent testing by other researchers," Beer told Reuters Health.
There is still a lot that needs to be done, however, before the technique can be put into practice, according to Beer.
"I am not sure that the exact type of analyzes we have done in this study will be used in the clinic," he said. He characterized the research as being in the "discovery phase," and said that the most predictive genes still need to be identified. Also, there is a need for "quick, accurate and dependable" methods of analyzing genes in tumor samples, Beer noted.
"These are all things that can be done, and I do think they will be," he said.
Even if high-risk patients can be identified, Beer said that there is a desperate need for appropriate therapies to treat aggressive lung cancer.
"This is where looking at the genes that are associated with aggressive behavior may provide some promise," he said.
The Michigan researcher pointed out that one of the genes that the study linked to poor survival was the gene for vascular endothelial growth factor (VEGF), which may influence the growth of blood vessels supplying lung cancer. He noted, "Targeting this gene product as a form of therapy for cancer is an active area of research in the scientific community."