Predictive value of tumor Ki-67 expression in two randomized trials of adjuvant chemoendocrine therapy for node-negative breast cancer.
Several small studies have reported that having a high percentage of breast tumor cells that express the proliferation antigen Ki-67 (ie, a high Ki-67 labeling index) predicts better response to neoadjuvant chemotherapy. However, the predictive value of a high Ki-67 labeling index for response to adjuvant chemotherapy is unclear. To investigate whether Ki-67 labeling index predicts response to adjuvant chemoendocrine therapy, we assessed Ki-67 expression in tumor tissue from 1924 (70%) of 2732 patients who were enrolled in two randomized International Breast Cancer Study Group trials of adjuvant chemoendocrine therapy vs endocrine therapy alone for node-negative breast cancer. A high Ki-67 labeling index was associated with other factors that predict poor prognosis. Among the 1521 patients with endocrine-responsive tumors, a high Ki-67 labeling index was associated with worse disease-free survival but the Ki-67 labeling index did not predict the relative efficacy of chemoendocrine therapy compared with endocrine therapy alone. Thus, Ki-67 labeling index was an independent prognostic factor but was not predictive of better response to adjuvant chemotherapy in these studies.
Viale
Giuseppe
G
Division of Pathology and Laboratory Medicine, European Institute of Oncology, University of Milan, Via Ripamoniti 435, Milan, Italy. giuseppe.viale@ieo.it
Regan
Meredith M
MM
Mastropasqua
Mauro G
MG
Maffini
Fausto
F
Maiorano
Eugenio
E
Colleoni
Marco
M
Price
Karen N
KN
Golouh
Rastko
R
Perin
Tiziana
T
Brown
R W
RW
Kovács
Anikó
A
Pillay
Komala
K
Ohlschlegel
Christian
C
Gusterson
Barry A
BA
Castiglione-Gertsch
Monica
M
Gelber
Richard D
RD
Goldhirsch
Aron
A
Coates
Alan S
AS
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000188:drug therapy* / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D003520:Cyclophosphamide / Q000008:administration & dosage; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D016015:Logistic Models; D008727:Methotrexate / Q000008:administration & dosage; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D011237:Predictive Value of Tests; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D013629:Tamoxifen / Q000008:administration & dosage; D016896:Treatment Outcome
D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D013629:Tamoxifen; D003520:Cyclophosphamide; D005472:Fluorouracil; D008727:Methotrexate