An open randomised trial of second-line endocrine therapy in advanced breast cancer: comparison of the Aromatase inhibitors letrozole and anastrozole

We were surprised to read in the conclusion of the article by Rose and colleagues [ [1] Rose C Vtoraya O Pluzanska A et al. An open randomised trial of second-line endocrine therapy in advanced breast cancer: comparison of the aromatase inhibitors letrozole and anastrozole. Eur. J. Cancer. 2003; 39: 2318-2327 Abstract Full Text Full Text PDF PubMed Scopus (179) Google Scholar ] comparing anastrozole with letrozole as second-line treatment for advanced breast cancer that `advanced breast cancer is more responsive to letrozole than to anastrozole' when no differences were reported for the primary endpoint and five of six secondary endpoints in this study. Rather, we would suggest that this study failed to demonstrate improved efficacy of letrozole over anastrozole and instead indicated that marginal differences in potency seen between the two agents did not translate into greater efficacy.