Comparison of methods to assess onset of breast development in the LEGACY Girls Study: methodological considerations for studies of breast cancer

Lauren C Houghton,Mary Beth Terry,Mary Jane De Souza,Esther M John,Karen O’Toole,Saundra S Buys,Mary B Daly,Julia A Knight,Mandy Goldberg,Angela R Bradbury,Wendy K Chung,Irene L Andrulis,Melissa L White

doi:10.1186/s13058-018-0943-9

Abstract

BackgroundYounger age at onset of breast development, which has been declining in recent decades, is associated with increased breast cancer risk independent of age at menarche. Given the need to study the drivers of these trends, it is essential to validate methods to assess breast onset that can be used in large-scale studies when direct clinical assessment of breast onset is not feasible.MethodsBreast development is usually measured by Tanner stages (TSs), assessed either by physical examination or by mother’s report using a picture-based Sexual Maturation Scale (SMS). As an alternative, a mother-reported Pubertal Development Scale (PDS) without pictures has been used in some studies. We compared agreement of SMS and PDS with each other (n = 1022) and the accuracy of PDS with clinical TS as a gold standard for the subset of girls with this measure (n = 282) using the LEGACY cohort. We further compared prediction of breast onset using ROC curves and tested whether adding urinary estrone 1-glucuronide (E1G) improved the AUC.ResultsThe agreement of PDS with SMS was high (kappa = 0.80). The sensitivity of PDS vs clinical TS was 86.6%. The AUCs for PDS alone and SMS alone were 0.88 and 0.79, respectively. Including E1G concentrations improved the AUC for both methods (0.91 and 0.86 for PDS and SMS, respectively).ConclusionsThe PDS without pictures is a highly accurate, sensitive, and specific method for assessing breast onset, especially in settings where clinical TS is not feasible. In addition, it is comparable to SMS methods with pictures and thus easier to implement in large-scale studies, particularly phone-based interviews where pictures may not be available. Urinary E1G can improve accuracy over than PDS or SMS alone.

Highlights

Younger age at onset of breast development, which has been declining in recent decades, is associated with increased breast cancer risk independent of age at menarche
One such method is the Sexual Maturation SMS Sexual Maturation Scale Model A (Scale) (SMS), a questionnaire-based tool that asks respondents to rate breast development based on pictures that correspond with the five Tanner stage (TS) [11]
Pubertal Development Scale (PDS) vs SMS In the overall cohort (N = 1022 with complete information; see Additional file 1: Table S1), PDS and SMS reports of breast onset stage were in high agreement (89.6%) (Table 1)

Summary

Introduction

Younger age at onset of breast development, which has been declining in recent decades, is associated with increased breast cancer risk independent of age at menarche. Clinician assessment via physical examination is considered the gold standard [9, 10], selfreports and guardian reports are often used in lieu of the physical examination, especially in large-scale epidemiological studies in which conducting physical examinations is often not feasible. One such method is the Sexual Maturation Scale (SMS), a questionnaire-based tool that asks respondents to rate breast development based on pictures that correspond with the five TSs [11]. A key advantage of the PDS is that it is question-based and does not involve pictures and can be queried over the phone and/or more included in questionnaires

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