Incidence of breast cancer attributable to breast density, modifiable and non-modifiable breast cancer risk factors\xa0in Singapore

Peh Joo Ho,Weang Kee Ho,Jingmei Li,Ken Wei Tan,Min-Han Tan,Kee Seng Chia,Fuh Yong Wong,Mikael Hartman,Hannah Si Hui Lau,Qian Yang,Wen Yee Chay

doi:10.1038/s41598-019-57341-7

Abstract

Incidence of breast cancer is rising rapidly in Asia. Some breast cancer risk factors are modifiable. We examined the impact of known breast cancer risk factors, including body mass index (BMI), reproductive and hormonal risk factors, and breast density on the incidence of breast cancer, in Singapore. The study population was a population-based prospective trial of screening mammography - Singapore Breast Cancer Screening Project. Population attributable risk and absolute risks of breast cancer due to various risk factors were calculated. Among 28,130 women, 474 women (1.7%) developed breast cancer. The population attributable risk was highest for ethnicity (49.4%) and lowest for family history of breast cancer (3.8%). The proportion of breast cancers that is attributable to modifiable risk factor BMI was 16.2%. The proportion of breast cancers that is attributable to reproductive risk factors were low; 9.2% for age at menarche and 4.2% for number of live births. Up to 45.9% of all breast cancers could be avoided if all women had breast density <12% and BMI <25 kg/m2. Notably, sixty percent of women with the lowest risk based on non-modifiable risk factors will never reach the risk level recommended for mammography screening. A combination of easily assessable breast cancer risk factors can help to identify women at high risk of developing breast cancer for targeted screening. A large number of high-risk women could benefit from risk-reduction and risk stratification strategies.

Highlights

Breast cancer is the most common cancer among women, accounting for 25% of all female cancers globally[1]
Previous studies on population attributable risk (PAR) of breast cancer risk factors have mostly been conducted in Western populations in the United States[8,9,10,11,12], Europe[13,14,15] and Australia[16]
Reported PARs of modifiable lifestyle risk factors ranged from 1% for alcohol consumption[10] to 39.3% for breast density assessed using the Breast Imaging Reporting and Data System (BI-RADS)[8]

Summary

Introduction

Breast cancer is the most common cancer among women, accounting for 25% of all female cancers globally[1]. Multiple risk factors for breast cancer are well-established; these include breast density, reproductive (parity and age at first birth), menstrual (menopausal status and age at menarche), and modifiable lifestyle factors such as body mass index (BMI), hormone replacement therapy (HRT) use and alcohol consumption[4,5,6]. Previous studies on PAR of breast cancer risk factors have mostly been conducted in Western populations in the United States[8,9,10,11,12], Europe[13,14,15] and Australia[16]. The PAR of breast cancer attributed to breast cancer risk factors have been studied mainly in East Asian populations (e.g. Korea[18] and mainland China[19,20]). We examined the impact of known breast cancer risk factors, including BMI, reproductive and hormonal risk factors, and breast density on the incidence of breast cancer

Methods

Results

Discussion

Conclusion