Double-Blind Randomized 12-Month Soy Intervention Had No Effects on Breast MRI Fibroglandular Tissue Density or Mammographic Density.
Soy supplementation by patients with breast cancer remains controversial. No controlled intervention studies have investigated the effects of soy supplementation on mammographic density in patients with breast cancer. We conducted a double-blind, randomized, placebo-controlled intervention study in previously treated patients with breast cancer (n = 66) and high-risk women (n = 29). We obtained digital mammograms and breast MRI scans at baseline and after 12 months of daily soy (50 mg isoflavones per day; n = 46) or placebo (n = 49) tablet supplementation. The total breast area (MA) and the area of mammographic density (MD) on the mammogram were measured using a validated computer-assisted method, and mammographic density percent (MD% = 100 × MD/MA) was determined. A well-tested computer algorithm was used to quantitatively measure the total breast volume (TBV) and fibroglandular tissue volume (FGV) on the breast MRI, and the FGV percent (FGV% = 100 × FGV/TBV) was calculated. On the basis of plasma soy isoflavone levels, compliance was excellent. Small decreases in MD% measured by the ratios of month 12 to baseline levels were seen in the soy (0.95) and the placebo (0.87) groups; these changes did not differ between the treatments (P = 0.38). Small decreases in FGV% were also found in both the soy (0.90) and the placebo (0.92) groups; these changes also did not differ between the treatments (P = 0.48). Results were comparable in patients with breast cancer and high-risk women. We found no evidence that soy supplementation would decrease mammographic density and that MRI might be more sensitive to changes in density than mammography.
Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, California. annawu@usc.edu.
Anna H
AH
Wu
Department of Medicine, University of Southern California Keck School of Medicine, Los Angeles, California.
Darcy
D
Spicer
Hematology Oncology, Louisiana State University, New Orleans, Louisiana.
Agustin
A
Garcia
Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, California.
Chiu-Chen
CC
Tseng
Department of Radiology, University of Southern California Keck School of Medicine, Los Angeles, California.
Linda
L
Hovanessian-Larsen
Department of Radiology, University of Southern California Keck School of Medicine, Los Angeles, California.
Pulin
P
Sheth
Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, California.
Sue Ellen
SE
Martin
Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, California.
Debra
D
Hawes
Department of Medicine, University of Southern California Keck School of Medicine, Los Angeles, California.
Christy
C
Russell
Department of Medicine, University of Southern California Keck School of Medicine, Los Angeles, California.
Heather
H
MacDonald
MBreast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Debu
D
Tripathy
Tu and Yuen Center for Functional Onco-Imaging, University of California, Irvine, Irvine, California.
Min-Ying
MY
Su
Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, California. Department of Nutrition, University of Oslo, Oslo, Norway. Cancer Registry of Norway, Oslo, Oslo, Norway.
Giske
G
Ursin
Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, California. Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York.
Malcolm C
MC
Pike
D000328:Adult; D000368:Aged; D000071060:Breast Density; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000000981:diagnostic imaging / Q000473:pathology; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D042361:Mammary Glands, Human / Q000002:abnormalities* / Q000187:drug effects; D008875:Middle Aged; D011859:Radiography; D030262:Soybean Proteins / Q000627:therapeutic use*; D013025:Glycine max
D030262:Soybean Proteins