Gefitinib (Iressa) could reduce the size of breast cancer tumours

May 17 2005

Giving women with early breast cancer a drug called gefitinib (Iressa) before surgery could reduce the size of their tumours, suggests a randomised trial published online today by The Lancet Oncology.

Gefitinib has been tested in clinical trials as a treatment for lung cancer but did not help patients live longer overall. Large-scale studies to assess its use in breast cancer, as a treatment prior to surgery, are now being designed, state the authors.

Some breast cancers are hormone sensitive and proliferate in the presence of oestrogen. But in trials where women with this type of breast cancer were given pre-surgical treatment to block hormones only half were found to respond. For this reason many doctors use chemotherapy prior to surgery, which can have negative side effects and cause substantial mortality.

A receptor called EGFR (epidermal growth factor receptor) is present on some hormone sensitive breast cancers and is associated with poor prognosis and failure to respond to hormone-blocking therapy. Charles Coombes (Imperial College and Hammersmith Hospital, London, UK) and colleagues tested whether inhibiting this receptor with a drug called gefitinib might suppress breast cancer cell proliferation. They recruited 56 postmenopausal women with breast cancer that was hormone sensitive and positive for EGFR from hospitals in London. 27 women were assigned gefitinib and an aromatase inhibitor called anastrozole (Arimidex) and 29 were assigned gefitinib and placebo for 4–6 weeks prior to receiving surgery. Tumours were reduced in size by 30-99% in 12 of 22 assigned gefitinib and anastrozole and in 14 of 28 patients assigned gefitinib and placebo.

Professor Coombes comments: “Gefitinib, combined with an aromatase inhibitor, might have a role in the neoadjuvant treatment of breast cancer by reducing the size of the tumour more rapidly. Studies are now being designed to assess this approach.”