MONDAY, April 22, 2013 (HealthDay News) -- Lung cancer patients carrying a rare gene mutation may experience delayed disease progression with drugs often taken by those with breast cancer, a new study suggests.
European researchers found that patients with non-small cell lung cancer who took drugs targeting so-called HER2 proteins -- which result from gene mutations in less than 5 percent of lung cancers -- experienced an extra five months of progression-free survival.
"We were favorably surprised by the outcome of patients and the promising activity of drugs that are usually dedicated to breast cancer patients," said study author Dr. Julien Mazieres, a professor of pulmonology at Larrey Hospital in Toulouse, France. "We do think that all lung [cancers] should be tested for HER2 as is done in France."
The study was published April 22 in the Journal of Clinical Oncology.
Non-small cell is the most common type of lung cancer -- the type seen in about 85 percent of lung cancer cases, according to the American Cancer Society. More than 200,000 Americans are diagnosed with lung cancer each year and 158,000 die from it, according to the U.S. Centers for Disease Control and Prevention.
HER2-positive cancer tests positive for a protein called human epidermal growth factor receptor 2, which feeds the growth of cancer cells and is caused by a gene mutation.
Mazieres and his colleagues identified this mutation in 65 non-small cell lung cancer patients, administering anti-HER2 drugs such as Herceptin (trastuzumab), which also is used to target HER2 in breast cancer patients.
Half of the patients were already at stage 4 lung cancer when diagnosed, while others were at earlier stages of the disease. Notably, most participants with the gene mutation were women, more than half of whom had never smoked.
The extra five months of progression-free survival experienced by patients undergoing HER2 therapies "is a big deal in the cancer business," said Dr. Norman Edelman, chief medical officer of the American Lung Association.
"It's not absolutely a new finding, but it's another study in what is a very exciting field now in cancer," Edelman said. "Up until now, we've treated cancers ... using an elephant gun. This new field looks at the genetic makeup of individual tumors to see if we can attack them in a specific way, not a general way."
Although only a small percentage of lung cancer patients carry this gene mutation, Edelman recommended that all patients be tested for it.
"It's useful and it's being done," he said. "If I had somebody I cared about who I thought had lung cancer, I would say to only go to a center where they're doing this testing. The odds are strong they will not be benefited [by anti-HER2 drugs], but lung cancer is a devastating disease."
Mazieres and Edelman agreed that future research in this area should focus on large clinical trials, which are costly but can tease out various genetic abnormalities that are important to tumor growth.
The U.S. National Library of Medicine has more about lung cancer.