Which patients benefit most from adjuvant aromatase inhibitors? Results using a composite measure of prognostic risk in the BIG 1-98 randomized trial

Viale, G. et al. (2011) Which patients benefit most from adjuvant aromatase inhibitors? Results using a composite measure of prognostic risk in the BIG 1-98 randomized trial. Annals of Oncology, 22(10), pp. 2201-2207. (doi: 10.1093/annonc/mdq738)

Abstract

Background: On average, aromatase inhibitors are better than tamoxifen when used as initial or sequential therapy for postmenopausal women with endocrine-responsive early breast cancer. Because there may be contraindications to their use based on side-effects or cost, we investigated subgroups in which aromatase inhibitors may be more or less important. Patients and methods: Breast International Group 1-98 trial randomized 6182 women among four groups comparing letrozole and tamoxifen with sequences of each agent; 5177 (84%) had centrally confirmed estrogen receptor (ER) positivity. We assessed whether centrally determined ER, progesterone receptor (PgR), human epidermal growth factor receptor 2, and Ki-67 labeling index, alone or in combination with other prognostic features, predicted the magnitude of letrozole effectiveness compared with either sequence or tamoxifen monotherapy. Results: Individually, none of the markers significantly predicted differential treatment effects. Subpopulation treatment effect pattern plot analysis of a composite measure of prognostic risk revealed three patterns. Estimated 5-year disease-free survival for letrozole monotherapy, letrozole -> tamoxifen, tamoxifen -> letrozole, and tamoxifen monotherapy were 96%, 94%, 93%, and 94%, respectively, for patients at lowest risk; 90%, 91%, 93%, and 86%, respectively, for patients at intermediate risk; and 80%, 76%, 74%, and 69%, respectively, for patients at highest risk. Conclusion: A composite measure of risk informs treatment selection better than individual biomarkers and supports the choice of 5 years of letrozole for patients at highest risk for recurrence

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gusterson, Professor Barry
• Authors: Viale, G., Regan, M. M., Dell'Orto, P., Mastropasqua, M. G., Maiorano, E., Rasmussen, B. B., MacGrogan, G., Forbes, J. F., Paridaens, R. J., Colleoni, M., Lang, I., Thurlimann, B., Mouridsen, H., Mauriac, L., Gelber, R. D., Price, K. N., Goldhirsch, A., Gusterson, B.A., and Coates, A. S.
• College/School: College of Medical Veterinary and Life Sciences
• Journal Name: Annals of Oncology
• ISSN: 0923-7534