Iressa or Tarceva when EGF are is not available – pro
For lung cancers caused by a mutation in the EGFR gene, Iressa works by blocking the EGFR protein that helps the cancer cells grow. The FDA based its approval on a study of 106 people with EGFR-mutated non-small cell lung cancer that had spread, and had not been treated before. The issue here is that e.g. effort testing is not possible because the original biopsy is not available or accessible and the new fine needle aspirate is insufficient for testing.
There is significant evidence that predates e.g. are for testing that elderly patients have a reasonable rate of response to EGFR directed drugs. Studies in Asia, where baseline EGF are positivity is higher , suggest that EGFR testing is helpful, but also that demographic evidence can be used to initiate therapy when EGF are testing is not available. “In those patients who have unknown EGFR mutation status, demographic and histopathology characteristics can be relied on to judge the potential efficacy of gefitinib use (Wu et al).”
Wu JY, Shih JY, Chen KY, Yang CH, Yu CJ, Yang PC. Gefitinib therapy in patients with advanced non-small cell lung cancer with or without testing for epidermal growth factor receptor (EGFR) mutations.Medicine (Baltimore). 2011 May;90(3):159-67.
Iressa, Prescribing Information 2017