*NEW* - Familial Risk, Cancer Conversion, and Surgical Management of Screen-Detected High-Risk Breast Lesions in Singapore

High-risk breast lesions (HRLs), including atypical ductal hyperplasia (ADH) and lobular carcinoma in situ (LCIS), are increasingly detected through population-based screening. However, three evidence gaps limit optimal management in Asian populations.

• The familial transmission of HRL-associated cancer risk (i.e. Does HRL cluster within families? Does having a mother or sister with an HRL increase a woman's risk of breast cancer? How does this compare with family history of breast cancer itself?) is unknown in Asia due to lack of multigenerational linkage studies.

• Cancer conversion rates (i.e. How many women go on to develop cancer after HRL diagnoses?) after screen recall are derived almost exclusively from Western cohorts and may not generalize to Asian populations.

• Variation in surgical management, particularly excision practices, may not reflect true malignancy risk, leading to potential overtreatment (i.e. Can we stratify HRLs for more intensive treatment? How long we do follow patients up after treatment?). 

Singapore’s nationwide screening program and longitudinal registry infrastructure provide a unique opportunity to address all three gaps within a single population-based framework. This study aims to use the MOH TRUST data to quantify familial breast cancer risk, subsequent breast cancer risk after abnormal breast screening, and variation in downstream clinical management in Singapore, and to assess whether patterns of care vary in relation to subsequent cancer risk across ethnic groups.