• 1/15/2004
  • International Journal of Cancer, December 2003

The new drug Iressa, which is approved for treating a type of lung cancer, may also be useful for treating oral cancers, Japanese researchers report. The drug is an inhibitor of a molecule called the epidermal growth factor receptor (EGFR), which is overactive in several cancers. Lab experiments show that Iressa triples the susceptibility of oral cancer cells to radiation therapy, by blocking the tumor’s ability to repair DNA damage after such treatment. In fact, “this new treatment strategy with radiation in combination with an EGFR inhibitor may help overcome oral cancer without surgery,” lead researcher Dr. Satoru Shintani suggested.

Shintani and colleagues at Ehime University School of Medicine came to these conclusions following a series of experiments with human oral cancer cell lines. The study is reported in the International Journal of Cancer.

Radiation or Iressa alone slowed proliferation of the cancer cells, and a cooperative anti-proliferative effect was seen when radiation was followed by Iressa treatment. After radiation, Iressa had a strong inhibitory effect on mechanisms in the tumor cells that repair DNA damage, and the researchers suggest this may help account for its enhancement of radiotherapy. Furthermore, when tumors were grafted into mice, the radiation and Iressa combination “caused a striking decrease in tumor cell proliferation.”

Thus they conclude that Iressa owes its action to “multiple mechanisms that may involve antiproliferative growth inhibition and effects on DNA repair after exposure to radiation.”