Premenopausal endocrine-responsive early breast cancer: who receives chemotherapy?
BACKGROUND
The role of chemotherapy in addition to combined endocrine therapy for premenopausal women with endocrine-responsive early breast cancer remains an open question, yet trials designed to answer it have repeatedly failed to adequately accrue. The International Breast Cancer Study Group initiated two concurrent trials in this population: in Premenopausal Endocrine Responsive Chemotherapy (PERCHE), chemotherapy use is determined by randomization and in Tamoxifen and Exemestane Trial (TEXT) by physician choice. PERCHE closed with inadequate accrual; TEXT accrued rapidly.


METHODS
From 2003 to 2006, 1317 patients (890 with baseline data) were randomly assigned to receive ovarian function suppression (OFS) plus tamoxifen or OFS plus exemestane for 5 years in TEXT. We explore patient-related factors according to whether or not chemotherapy was given using descriptive statistics and classification and regression trees.


RESULTS
Adjuvant chemotherapy was chosen for 64% of patients. Lymph node status was the predominant determinant of chemotherapy use (88% of node positive treated versus 46% of node negative). Geography, patient age, tumor size and grade were also determinants, but degree of receptor positivity and human epidermal growth factor receptor 2 status were not.


CONCLUSIONS
The perceived estimation of increased risk of relapse is the primary determinant for using chemotherapy despite uncertainties regarding the degree of benefit it offers when added to combined endocrine therapy in this population.
Regan
M M
MM
IBCSG Statistical Center, Dana-Farber Cancer Institute, Harvard School of Public Health, Boston, MA, USA. Electronic address: mregan@jimmy.harvard.edu.
Pagani
O
O
Oncology Institute of Southern Switzerland, Ospedale Italiano, Viganello, Lugano; Swiss Group for Clinical Cancer Research, Bern, Switzerland.
Walley
B
B
Tom Baker Cancer Centre, Calgary, Alberta, Canada.
Torrisi
R
R
European Institute of Oncology, Milan, Italy.
Perez
E A
EA
Mayo Clinic Jacksonville, Jacksonville, FL, USA.
Francis
P
P
Peter MacCallum Cancer Centre, Melbourne, Australia.
Fleming
G F
GF
University of Chicago Medical Center, Chicago, IL, USA.
Price
K N
KN
IBCSG Statistical Center, Frontier Science and Technology Research Foundation, Boston, MA, USA.
Thürlimann
B
B
Swiss Group for Clinical Cancer Research, Bern, Switzerland; Senology Center of Eastern Switzerland, Kantonsspital, St Gallen, Switzerland.
Maibach
R
R
IBCSG Coordinating Center, Bern, Switzerland.
Castiglione-Gertsch
M
M
IBCSG Coordinating Center, Bern, Switzerland.
Coates
A S
AS
International Breast Cancer Study Group, Bern, Switzerland; University of Sydney, Sydney, Australia.
Goldhirsch
A
A
Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Gelber
R D
RD
IBCSG Statistical Center, Dana-Farber Cancer Institute, Frontier Science and Technology Research Foundation, Harvard School of Public Health, Boston, MA, USA.
D000730:Androstadienes / Q000008:administration & dosage; D000970:Antineoplastic Agents / Q000008:administration & dosage; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D003657:Decision Making; D005260:Female; D017273:Goserelin / Q000008:administration & dosage; D006801:Humans; D017697:Premenopause; D016032:Randomized Controlled Trials as Topic; D013629:Tamoxifen / Q000008:administration & dosage
D000730:Androstadienes; D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; D013629:Tamoxifen; D017273:Goserelin; C056516:exemestane