Relative effectiveness of letrozole compared with tamoxifen for patients with lobular carcinoma in the BIG 1-98 Trial

Metzger Filho, O. et al. (2015) Relative effectiveness of letrozole compared with tamoxifen for patients with lobular carcinoma in the BIG 1-98 Trial. Journal of Clinical Oncology, 33(25), pp. 2772-2779. (doi: 10.1200/jco.2015.60.8133) (PMID:26215945)

Full text not currently available from Enlighten.

Abstract

Purpose: To evaluate the relative effectiveness of letrozole compared with tamoxifen for patients with invasive ductal or lobular carcinoma. Patients and Methods: Patients diagnosed with early-stage invasive ductal carcinoma (IDC) or classic invasive lobular carcinoma (ILC) who were randomly assigned onto the Breast International Group (BIG) 1-98 trial and who had centrally reviewed pathology data were included (N = 2,923). HER2-negative IDC and ILC were additionally classified as hormone receptor–positive with high (luminal B [LB] –like) or low (luminal A [LA] –like) proliferative activity by Ki-67 labeling index. Survival analyses were performed with weighted Cox models that used inverse probability of censoring weighted modeling. Results: The median follow-up time was 8.1 years. In multivariable models for disease-free survival (DFS), significant interactions between treatment and histology (ILC or IDC; P = .006) and treatment and subgroup (LB like or LA like; P = .01) were observed. In the ILC subset, there was a 66% reduction in the hazard of a DFS event with letrozole for LB (hazard ratio [HR], 0.34; 95% CI, 0.21 to 0.55) and a 50% reduction for LA subtypes (HR, 0.50; 95% CI, 0.32 to 0.78). In the IDC subset, there was a significant 35% reduction in the hazard of a DFS event with letrozole for the LB subtype (HR, 0.65; 95% CI, 0.53 to 0.79), but no difference between treatments was noted for IDC and the LA subtype (HR, 0.95; 95% CI, 0.76 to 1.20). Conclusion: The magnitude of benefit of adjuvant letrozole is greater for patients diagnosed with lobular carcinoma versus ductal carcinoma.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mallon, Dr Elizabeth and Gusterson, Professor Barry
Authors: Metzger Filho, O., Giobbie-Hurder, A., Mallon, E., Gusterson, B., Viale, G., Winer, E. P., Thurlimann, B., Gelber, R. D., Colleoni, M., Ejlertsen, B., Debled, M., Price, K. N., Regan, M. M., Coates, A. S., and Goldhirsch, A.
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
Journal Name:Journal of Clinical Oncology
Publisher:American Society of Clinical Oncology
ISSN:0732-183X
ISSN (Online):1527-7755

University Staff: Request a correction | Enlighten Editors: Update this record