New guidelines recommend lung cancer patients be genetically tested to determine whether they are amenable to a class of drugs called tyrosine kinase inhibitors. Patients with EGFR or ALK mutations could benefit more from such targeted therapies, and suffer fewer side effects, than with chemotherapy.
“In the U.S., up to 20% of patients with lung adenocarcinoma, the most common type of lung cancer, will test positive for one of the two biomarkers,” says Philip Cagle, pulmonary pathologist at the Methodist Hospital in Houston, Texas, and one of the authors of the new guidelines. These EGFR and ALK abnormalities can be effectively treated with erlotinib (Tarceva) and crizotinib (Xalkori), respectively. Other drugs in the same tyrosine kinase inhibitor family include gefitinib (Iressa), currently only available outside the U.S., and afatinib, which may be approved by the U.S. Food and Drug Administration (FDA) later in 2013.
The guidelines, jointly developed by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology, form the first internationally agreed standard for biomarker testing in lung cancer. They stipulate that all advanced adenocarcinoma patients should be tested, regardless of sex, age, or ethnicity. Smoking history should also not exclude patients from testing, as 5% to 10% of smokers could harbor one of these mutations, making them suitable for targeted therapy. Intended for clinicians and pathologists, the guidelines also address when and how testing should be performed, with a view to expanding the use of targeted drugs and making testing for genetic abnormalities in lung cancer routine, much like it already is in breast cancer.
The investigators used the results of more than 500 published research articles to arrive at their recommendations. “Pathologists who specialize in molecular diagnostics and lung cancer collaborated to create the guideline to minimize variation and provide greater precision in the care of patients,” explained lead author Neal Lindeman of Brigham & Women’s Hospital in Boston, Massachusetts. The investigators encourage EGFR and ALK testing at diagnosis of earlier stage I, II, or III disease and say that testing for mutations in these two genes should be prioritized over others. In addition, a turnaround of no more than 10 days for test results is advised, as decisions about treatment strategies may need to be made quickly, especially in cases of advanced adenocarcinoma.
Identifying these biomarkers could expand patients’ treatment options to include targeted therapies like tyrosine kinase inhibitors, which tend to be better tolerated than chemotherapy and also extend survival time. The new biomarker guidelines are explained in a series of videos; a patient guide is also available.