High Pathologic Response Rate Of Hepatic Colorectal Cancer Metastases (Hcrm) Following Neoadjuvant Bevacizumab (Bev) -Based Treatment (Tx)

529 Background: BIG 1-98 is a randomized, phase III study that compares five years of tamoxifen (tam) or letrozole (let), (monotherapy arms), or their sequences (tam-let or let-tam) in post-menopausal women with ER+ early BC. In the monotherapy arms, the magnitude of benefit of adjuvant let compared with tam varies by histology (greater in invasive lobular carcinoma (ILC) than invasive ductal carcinoma (IDC)). In this analysis we investigate the magnitude of benefit of let compared to tam-let and let-tam according to histology (IDC and ILC) at 96 months of median follow-up. Methods: There were 4,634 patients enrolled in the let, tam-let and let-tam arms of BIG-98. This analysis includes patients with centrally-reviewed histological subtype (n=4,223); classified as classic ILC or IDC (n=3,790); and with centrally reviewed ER, PgR and Ki67 (n=3,212). Results: The 8-year DFS and OS univariate estimates (±SE) for IDC and ILC are presented in the Table. When correcting for classic clinicopathological variables...