Non-invasive optical spectroscopic monitoring of breast development during puberty.
Tanner staging (TS), a five-stage classification indicating no breast tissue (TS1) to full breast development (TS5), is used both in health research and clinical care to assess the onset of breast development (TS2) and duration in each stage. Currently, TS is measured both visually and through palpation but non-invasive methods will improve comparisons across settings.



We used optical spectroscopy (OS) measures from 102 girls at the Ontario site of the LEGACY girls study (average age 12 years, range 10.0-15.4 years) to determine whether breast tissue optical properties map to each TS. We further examined whether these properties differed by age, body mass index (BMI), and breast cancer risk score (BCRS) by examining the major principal components (PC).



Age and BMI increased linearly with increasing TS. Eight PCs explained 99.9% of the variation in OS data. Unlike the linear increase with age and BMI, OS components had distinct patterns by TS: the onset of breast development (TS1 to TS2) was marked by elevation of PC3 scores indicating an increase in adipose tissue and decrease in signal from the pectoral muscle; transition to TS3 was marked by elevation of PC6 and PC7 and decline of PC2 scores indicating an increase in glandular or dense tissue; and transition to TS4+ by decline of PC2 scores representing a further increase in glandular tissue relative to adipose tissue. Of the eight PCs, three component scores (PC4, PC5, and PC8) remained in the best-fitting model of BCRS, suggesting different levels of collagen in the breast tissue by BCRS.



Our results suggest that serial measures of OS, a non-invasive assessment of breast tissue characteristics, can be used as an objective outcome that does not rely on visual inspection or palpation, for studying drivers of breast development.
Princess Margaret Cancer Centre, University Health Network, 101 College Street, Toronto, ON, M5G1L7, Canada.|Medical Biophysics, University of Toronto, 101 College Street, Toronto, ON, M5G1L7, Canada.
Lothar
L
Lilge
Department of Epidemiology, Columbia University Mailman School of Public Health, New York, NY, USA.|Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, USA.
Mary Beth
MB
Terry
Medical Biophysics, University of Toronto, 101 College Street, Toronto, ON, M5G1L7, Canada.
Jane
J
Walter
Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada.
Dushanthi
D
Pinnaduwage
Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada.
Gord
G
Glendon
Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada.
Danielle
D
Hanna
Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada.
Mai-Liis
ML
Tammemagi
Departments of Medicine and Medical Ethics & Health Policy, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA, USA.
Angela
A
Bradbury
Department of Medicine, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT, USA.
Saundra
S
Buys
Department of Clinical Genetics, Fox Chase Cancer Center, Philadelphia, PA, USA.
Mary
M
Daly
Cancer Prevention Institute of California, Fremont, CA, USA.|Department of Health Research & Policy (Epidemiology), and Stanford Cancer Institute, Stanford School of Medicine, Stanford, CA, USA.
Esther M
EM
John
Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada.|Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
Julia A
JA
Knight
Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada. andrulis@lunenfeld.ca.|Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada. andrulis@lunenfeld.ca.
Irene L
IL
Andrulis
D000293:Adolescent; D015992:Body Mass Index; D001940:Breast / Q000000981:diagnostic imaging* / Q000254:growth & development*; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology; D002648:Child; D005260:Female; D006801:Humans; D009864:Ontario / Q000453:epidemiology; D061848:Optical Imaging / Q000379:methods; D011159:Population Surveillance; D011627:Puberty; D012372:ROC Curve; D012741:Sexual Maturation; D013057:Spectrum Analysis / Q000379:methods
Breast cancer family history; Breast development; LEGACY girls study; Optical spectroscopy; Tanner staging