WEDNESDAY, March 23 (HealthDay News) -- A new study helps
explain how some lung cancers become resistant to targeted drug
Researchers at the Massachusetts General Hospital Cancer Center
analyzed tumor samples from 37 patients with non-small cell lung
cancer, the leading cause of cancer death worldwide, and identified
two new genetic changes associated with resistance.
They also confirmed resistance-related genetic changes
identified in previous studies.
The MGH team also discovered that the cellular nature of some
tumors changes in response to treatment and that genetic mutations
associated with drug resistance can disappear after treatment is
The findings highlight the importance of monitoring the
molecular status of lung cancer tumors throughout the treatment
process, the researchers said.
"It is really remarkable how much we oncologists assume about a tumor based on a single biopsy taken at one time, usually the time of diagnosis," lead author Dr. Lecia Sequist said in an MGH news release. "Many cancers can evolve in response to exposure to different therapies over time, and we may be blind to the implications of these changes simply because we haven't been looking for them."
"Our findings suggest that, when feasible, oncogene-driven cancers should be interrogated with repeat biopsies throughout the course of the disease," Sequist said. "Doing so could both contribute to greater understanding of acquired resistance and give caregivers better information about whether resumption of targeted therapy or initiation of a standard therapy would be most appropriate for an individual patient."
The study appears March 23 in the journal
Science Translational Medicine.
The American Cancer Society has more about
non-small-cell lung cancer.