Purpose To evaluate the prognostic and predictive value of Ki-67 labeling index (LI) in a trial comparing letrozole (Let) with tamoxifen (Tam) as adjuvant therapy in postmenopausal women with early breast cancer. Patients and Methods Breast International Group ( BIG) trial 1-98 randomly assigned 8,010 patients to four treatment arms comparing Let and Tam with sequences of each agent. Of 4,922 patients randomly assigned to receive 5 years of monotherapy with either agent, 2,685 had primary tumor material available for central pathology assessment of Ki-67 LI by immunohistochemistry and had tumors confirmed to express estrogen receptors after central review. The prognostic and predictive value of centrally measured Ki- 67 LI on disease-free survival (DFS) were assessed among these patients using proportional hazards modeling, with Ki- 67 LI values dichotomized at the median value of 11%. Results Higher values of Ki- 67 LI were associated with adverse prognostic factors and with worse DFS (hazard ratio [HR; high: low] = 1.8; 95% CI, 1.4 to 2.3). The magnitude of the treatment benefit for Let versus Tam was greater among patients with high tumor Ki- 67 LI (HR [Let: Tam] = 0.53; 95% CI, 0.39 to 0.72) than among patients with low tumor Ki- 67 LI (HR [Let: Tam] = 0.81; 95% CI, 0.57 to 1.15; interaction P = .09).Conclusion Ki- 67 LI is confirmed as a prognostic factor in this study. High Ki- 67 LI levels may identify a patient group that particularly benefits from initial Let adjuvant therapy.

Prognostic and predictive value of centrally reviewed Ki-67 labeling index in postmenopausal women with endocrine-responsive breast cancer : results from Breast International Group Trial 1-98 comparing adjuvant tamoxifen with letrozole / G. Viale, A. Giobbie-Hurder, M.M. Regan, A.S. Coates, M.G. Mastropasqua, P. Dell'Orto, E. Maiorano, G. MacGrogan, S.G. Braye, C. Ohlschlegel, P. Neven, Z. Orosz, W.P. Olszewski, F. Knox, B. Thürlimann, K.N. Price, M. Castiglione-Gertsch, R.D. Gelber, B.A. Gusterson, A. Goldhirsch. - In: JOURNAL OF CLINICAL ONCOLOGY. - ISSN 0732-183X. - 26:34(2008 Dec 01), pp. 5569-5575.

Prognostic and predictive value of centrally reviewed Ki-67 labeling index in postmenopausal women with endocrine-responsive breast cancer : results from Breast International Group Trial 1-98 comparing adjuvant tamoxifen with letrozole

G. Viale
Primo
;
2008

Abstract

Purpose To evaluate the prognostic and predictive value of Ki-67 labeling index (LI) in a trial comparing letrozole (Let) with tamoxifen (Tam) as adjuvant therapy in postmenopausal women with early breast cancer. Patients and Methods Breast International Group ( BIG) trial 1-98 randomly assigned 8,010 patients to four treatment arms comparing Let and Tam with sequences of each agent. Of 4,922 patients randomly assigned to receive 5 years of monotherapy with either agent, 2,685 had primary tumor material available for central pathology assessment of Ki-67 LI by immunohistochemistry and had tumors confirmed to express estrogen receptors after central review. The prognostic and predictive value of centrally measured Ki- 67 LI on disease-free survival (DFS) were assessed among these patients using proportional hazards modeling, with Ki- 67 LI values dichotomized at the median value of 11%. Results Higher values of Ki- 67 LI were associated with adverse prognostic factors and with worse DFS (hazard ratio [HR; high: low] = 1.8; 95% CI, 1.4 to 2.3). The magnitude of the treatment benefit for Let versus Tam was greater among patients with high tumor Ki- 67 LI (HR [Let: Tam] = 0.53; 95% CI, 0.39 to 0.72) than among patients with low tumor Ki- 67 LI (HR [Let: Tam] = 0.81; 95% CI, 0.57 to 1.15; interaction P = .09).Conclusion Ki- 67 LI is confirmed as a prognostic factor in this study. High Ki- 67 LI levels may identify a patient group that particularly benefits from initial Let adjuvant therapy.
randomized-trial ; cell-proliferation ; mitotic index ; expression ; carcinoma ; therapy ; marker ; chemotherapy ; anastrozole ; receptors
Settore MED/36 - Diagnostica per Immagini e Radioterapia
Settore MED/08 - Anatomia Patologica
1-dic-2008
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/70833
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