Formation of Cohort

The overall principal investigator (PI), Mikael Hartman, has worked as a breast surgeon at National University Hospital Singapore and an epidemiologist at Saw Swee Hock School of Public Health since 2009. He has assembled a multidisciplinary research team to tackle the complex problems in breast cancer etiology and genetic risk factors, early detection, prognostication, pharmacogenetics, quality of life and survivorship in a multi-ethnic Asian setting. Over the years, the team has delivered high quality research outputs from previous research grants. With the PI’s clinical experience and expertise in molecular epidemiology, and support from a team of dedicated breast surgeons, medical oncologists, biostatisticians, geneticists and computer scientists, the PI and team are well equipped to conduct large-scale pharmacogenomic studies which involve extensive clinical data and utilize cutting-edge genomic technologies.

The Singapore Breast Cancer Cohort Study (SGBCC) is a multi-institutional cohort established in 2009. It first started at the National University Hospital in 2010, and then extended to six other tertiary hospitals, namely KK Women’s and Children’s Hospital (in 2011), Tan Tock Seng hospital (in 2014), National Cancer Centre Singapore (in 2014), Singapore General Hospital (in 2015), Changi General Hospital (in 2016) and Ng Teng Fong General Hospital (in 2018). These public hospitals are estimated to treat 76% of total breast cancer cases in Singapore.

Study Procedure

At each participating site, existing and newly diagnosed breast cancer patients (Singaporean/ Permanent Resident) are invited to join this research study during outpatient visits. A structured questionnaire is then administrated by coordinators to collect detailed information on socio-demographic and lifestyle factors, medical history of previous or existing illnesses, family history of cancer, menstrual and reproductive risk factors for breast cancer, and participation and attitudes towards mammographic screening program. Clinical data are retrieved from medical records and include, but not limited to tumour characteristics and treatment modalities.

Blood specimens of 20ml are obtained by the trained nurses or phlebotomists in the clinics after the interview or during their subsequent clinical visit. Blood specimens are processed at a central biobank on a weekly basis. Upon receipt of a biological specimen, the whole blood sample is separated into multiple aliquots of plasma, buffy coat, red blood cell, serum and blood clot after centrifugation. All aliquots are stored at a temperature of -80 °C and an inventory tracking system is maintained to link with the biological specimen at all times. If the patient refuses donation of blood, saliva specimen is collected by spitting into an Oragene® DNA OG-500 self-collection kit manufactured by DNA Genotek®. Saliva specimen in the original collection tube is stored at -80 °C before DNA extraction. DNA is extracted from the buffy coat and saliva on a regular basis by the appointed laboratory according to the manufacturer’s protocol.

Current Status

The SGBCC grew quickly in the first two years of recruitment at each participating site, mainly driven by prevalent cases of participants on routine surveillance, and then slowed down to a steady rate of 200 newly diagnosed patients per year thereafter. As of 31 August 2021, we have successfully recruited 12,088 breast cancer patients into the study. The overall participation rate was 83% and about 78% subjects contributed bio-specimens.