Comparison Of Methods For Detection Of Fulvestrant-Induced Changes In Breast Tumor Estrogen And Progesterone Receptor Expression In A Neoadjuvant Trial (Newest)

e11602^ Background: Fulvestrant downregulates breast tumor estrogen and progesterone receptor (ER and PgR) levels in a dose-dependent manner. Using an Automated Cellular Imaging System (ACIS), NEWEST reported that 4-wks’ treatment with fulvestrant high-dose (HD, 500mg/month+500mg on Day 14 of Month 1) significantly reduced ER levels in primary breast tumors v approved-dose (AD, 250mg/month). However, no significant difference was detected between the two doses on PgR levels. To allow comparison with previous studies, a non-automated H-score assessment was performed and compared with ACIS. Methods: ER and PgR H-scores were derived by manual assessment of % tumor cells in each of 5 staining categories (negative, very weak, weak, moderate, strong) in the same sections scored by ACIS. This microscopic assessment was performed by 2 experienced observers blind to ACIS and clinical data. Mean % changes in H-scores were then calculated (table). Results: Both scoring methods showed a greater effect for fulvestrant HD v AD on ER expression at Wk 4, but H-score provided better dose discrimination. ACIS showed no difference between fulvestrant HD v AD on PgR expression at Wk 4, however, a significantly greater reduction in PgR expression was detected with fulvestrant HD using H-score. Conclusions: The choice of scoring method for determining ER and PgR expression in pharmacodynamic studies such as NEWEST is critical. Compared with H-scores, ACIS has a narrower dynamic range and reduced ability to discriminate fulvestrant HD v AD, particularly on PgR expression. [Table: see text] ASCO Conflict of Interest Policy and Exceptions In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519–521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting. For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2009 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings. For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .