TY - JOUR
T1 - Analyses adjusting for selective crossover show improved overall survival with adjuvant letrozole compared with tamoxifen in the BIG 1-98 study
AU - Colleoni, Marco
AU - Giobbie-Hurder, Anita
AU - Regan, Meredith M
AU - Thürlimann, Beat
AU - Mouridsen, Henning
AU - Mauriac, Louis
AU - Forbes, John F
AU - Paridaens, Robert
AU - Láng, István
AU - Smith, Ian
AU - Chirgwin, Jacquie
AU - Pienkowski, Tadeusz
AU - Wardley, Andrew
AU - Price, Karen N.
AU - Gelber, Richard D
AU - Coates, Alan S
AU - Goldhirsch, Aron
PY - 2011/3/20
Y1 - 2011/3/20
N2 - Purpose: Among postmenopausal women with endocrine-responsive breast cancer, the aromatase inhibitor letrozole, when compared with tamoxifen, has been shown to significantly improve disease-free survival (DFS) and time to distant recurrence (TDR). We investigated whether letrozole monotherapy prolonged overall survival (OS) compared with tamoxifen monotherapy. Patients and Methods: Of 8,010 postmenopausal women with hormone receptor-positive, early breast cancer enrolled on the Breast International Group (BIG) 1-98 study, 4,922 were randomly assigned to 5 years of continuous adjuvant therapy with either letrozole or tamoxifen. Of 2,459 patients enrolled in the tamoxifen treatment arm, 619 (25.2%) selectively crossed over to either adjuvant or extended letrozole after initial trial results were presented in January 2005. To gain better estimates of relative treatment effects in the presence of selective crossover, we used inverse probability of censoring weighted (IPCW) modeling. Results: Weighted Cox models, by using IPCW, estimated a statistically significant, 18% reduction in the hazard of an OS event with letrozole treatment (hazard ratio [HR], 0.82; 95% CI, 0.70 to 0.95). Estimates of 5-year OS on the basis of IPCW were 91.8% and 90.4% for letrozole and tamoxifen, respectively. The HRs of DFS and TDR events by using IPCW modeling were 0.83 (95% CI, 0.74 to 0.94) and 0.80 (95% CI, 0.67 to 0.94), respectively (P < .05 for DFS, OS, and TDR). Median follow-up was 74 months. Conclusion: Adjuvant treatment with letrozole, compared with tamoxifen, significantly reduces the risk of death, the risk of recurrent disease, and the risk of recurrence at distant sites in postmenopausal women with hormone receptor - positive breast cancer.
AB - Purpose: Among postmenopausal women with endocrine-responsive breast cancer, the aromatase inhibitor letrozole, when compared with tamoxifen, has been shown to significantly improve disease-free survival (DFS) and time to distant recurrence (TDR). We investigated whether letrozole monotherapy prolonged overall survival (OS) compared with tamoxifen monotherapy. Patients and Methods: Of 8,010 postmenopausal women with hormone receptor-positive, early breast cancer enrolled on the Breast International Group (BIG) 1-98 study, 4,922 were randomly assigned to 5 years of continuous adjuvant therapy with either letrozole or tamoxifen. Of 2,459 patients enrolled in the tamoxifen treatment arm, 619 (25.2%) selectively crossed over to either adjuvant or extended letrozole after initial trial results were presented in January 2005. To gain better estimates of relative treatment effects in the presence of selective crossover, we used inverse probability of censoring weighted (IPCW) modeling. Results: Weighted Cox models, by using IPCW, estimated a statistically significant, 18% reduction in the hazard of an OS event with letrozole treatment (hazard ratio [HR], 0.82; 95% CI, 0.70 to 0.95). Estimates of 5-year OS on the basis of IPCW were 91.8% and 90.4% for letrozole and tamoxifen, respectively. The HRs of DFS and TDR events by using IPCW modeling were 0.83 (95% CI, 0.74 to 0.94) and 0.80 (95% CI, 0.67 to 0.94), respectively (P < .05 for DFS, OS, and TDR). Median follow-up was 74 months. Conclusion: Adjuvant treatment with letrozole, compared with tamoxifen, significantly reduces the risk of death, the risk of recurrent disease, and the risk of recurrence at distant sites in postmenopausal women with hormone receptor - positive breast cancer.
UR - http://www.scopus.com/inward/record.url?scp=79952748821&partnerID=8YFLogxK
U2 - 10.1200/JCO.2010.31.6455
DO - 10.1200/JCO.2010.31.6455
M3 - Article
AN - SCOPUS:79952748821
VL - 29
SP - 1117
EP - 1124
JO - Journal of Clinical Oncology
JF - Journal of Clinical Oncology
SN - 0732-183X
IS - 9
ER -