Lung cancer is often dramatically different in women than it is in men, U.S. researchers reported on Tuesday in another study that suggests ways to tailor treatment for cancer patients.
They also found that some elderly patients have forms of lung cancer that make them likely to benefit from chemotherapy, even though the treatments can be harsh.
The study, published in the Journal of the American Medical Association, is the latest in a string of experiments that show cancer is far more complex genetically than doctors dreamed of even a few years ago.
Together, the studies may open better ways to target the hit-and-miss treatments that can sicken some patients while saving the lives of others.
Dr. Anil Potti of Duke University in North Carolina and colleagues studied 787 patients with non-small cell lung cancer, looking at how well they did on treatment and analyzing their DNA.
They looked at genes known to be involved in cancer — epidermal growth factor receptor or EGFR, Ras, STAT3 and others.
"Our study supports two key findings: First, the biology of lung cancer in women is dramatically different from what we see in men," Potti said in a statement.
"Women, in general, have a less complex disease, at least in terms of the numbers of molecular pathways involved. We also discovered that there is a subset of elderly patients would probably benefit from treatments that we've normally reserved for younger patients."
Some of the findings were not surprising. Patients whose cancer came back the quickest after treatment had tumors rich in genes activated for tumor spread or those that help tumors grow new blood supplies.
THOUSANDS OF MUTATIONS
The researchers noted that genetic cancer tests are far more available than in the past and often deliver results within a week. It may be possible to start defining patients by their specific genetic tumor signatures, they said.
In December British scientists who sequenced all the DNA from lung tumor tissue said they found more than 23,000 mutations.
Several cancer drugs are already targeted to some of the genetic mutations the researchers found, and studies have hinted at some of the variability seen in lung cancer.
For instance, AstraZeneca's lung cancer pill Iressa, or gefitinib, has been show to work far better than chemotherapy in people from East Asia with EGFR mutations.
Roche's erlotinib, sold under the brand name Tarceva, is also designed to affect tumors with certain EGFR mutations.
Eli Lilly's Erbitux, sold by Merck KGaA and Bristol-Myers Squibb, also targets mutated EGFR. The potential markets are huge — Erbitux had 2008 sales of $1.6 billion.
Lung cancer is the leading cause of cancer death globally, killing 1.3 million people a year. It does not cause symptoms right away so most people are diagnosed after it has spread — one reason the survival rate is only about 15 percent.
There are dozens of drugs on the market to treat lung cancer and oncologists make an art of matching the therapy to the patient.
"So being able to better understand the disease and stratify patients by their individual molecular profiles means we can do a much better job pairing the right drug with the right patient," said Duke's Dr. Jeffrey Crawford, who worked on the study.