The Massachusetts General Hospital Cancer Center researchers said the study -- the first such U.S. clinical genetic screening trial -- supports the use of targeted therapies as primary treatments, rather than only after standard chemotherapy has failed.

Investigators found gefitinib (Iressa) treatment considerably improved the outcomes for non-small-cell-lung-cancer, although additional research is required before such a strategy can be used for routine treatment.

"This is a pivotal clinical trial that demonstrates the power of personalized medicine in lung cancer treatment," said Dr. Lecia Sequist, who led the study. "It is an exciting glimpse into what we hope is the future of cancer care. Instead of a 'one size fits all' therapy, we are moving towards finding the best treatment for each patient."

The report appears in the Journal of Clinical Oncology.