Menstrual cycle and surgical treatment of breast cancer: findings from the NCCTG N9431 study.
OBJECTIVE
For nearly two decades, multiple retrospective reports, small prospective studies, and meta-analyses have arrived at conflicting results regarding the value of timing surgical intervention for breast cancer on the basis of menstrual cycle phase. We present the results of a multi-cooperative group, prospective, observational trial of menstrual cycle phase and outcome after breast cancer surgery, led by the North Central Cancer Treatment Group (NCCTG) in collaboration with the National Surgical Adjuvant Breast and Bowel Project (NSABP) and the International Breast Cancer Study Group (IBCSG).


METHODS
Premenopausal women age 18 to 55 years, who were interviewed for menstrual history and who were surgically treated for stages I to II breast cancer, had serum drawn within 1 day of surgery for estradiol, progesterone, and luteinizing hormone levels. Menstrual history and hormone levels were used to determine menstrual phase: luteal, follicular, and other. Disease-free survival (DFS) and overall survival (OS) rates were determined by Kaplan-Meier method and were compared by using the log-rank test and Cox proportional hazard modeling.


RESULTS
Of 1,118 women initially enrolled, 834 women comprised the study cohort: 230 (28%) in luteal phase; 363 (44%) in follicular phase; and 241 grouped as other. During a median follow-up of 6.6 years, and in analysis that accounted for nodal disease, estrogen receptor status, adjuvant radiation therapy or chemotherapy, neither DFS nor OS differed with respect to menstrual phase. The 5-year DFS rates were 82.7%, 82.1%, and 79.2% for follicular, luteal, or other phases, respectively. Corresponding OS survival rates were 91.9%, 92.2%, and 91.8%, respectively.


CONCLUSIONS
When menstrual cycle phases were strictly defined, neither DFS nor OS differed between women who underwent surgery during the follicular phase versus the luteal phase. Nearly 30% of the patients did not meet criteria for either follicular- or luteal-phase categories.
Grant
Clive S
CS
Division of General Surgery, Mayo Clinic, North Central Cancer Treatment Group, Dept of Surgery, 200 1st St SW, Rochester, MN 55905, USA. cgrant@mayo.edu
Ingle
James N
JN
Suman
Vera J
VJ
Dumesic
Daniel A
DA
Wickerham
D Lawrence
DL
Gelber
Richard D
RD
Flynn
Patrick J
PJ
Weir
Lorna M
LM
Intra
Mattia
M
Jones
Wayne O
WO
Perez
Edith A
EA
Hartmann
Lynn C
LC
D000328:Adult; D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000097:blood / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005498:Follicular Phase / Q000097:blood*; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008183:Luteal Phase / Q000097:blood*; D008297:Male; D008408:Mastectomy / Q000379:methods* / Q000401:mortality; D008597:Menstrual Cycle / Q000097:blood; D008875:Middle Aged; D009367:Neoplasm Staging; D017697:Premenopause; D011300:Preoperative Care / Q000379:methods; D011336:Probability; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult