Therefore, a possible interpretation for the findings of our study is that women with ER positive tumours, which have been treated chronically up to 5 years in the adjuvant setting with the antioestrogen tamoxifen, may have eventually developed a MBC in which the EGFR driven pathway has become important for cancer cell growth and for such reason become sensitive to gefitinib cialis without prescription PMID 34497589 Free PMC article