Published
Managing hereditary breast and ovarian cancer (HBOC) syndrome: genetic testing and risk-reducing interventions ACRs
5 November 2026
Condition
Gynaecological
Neoplasms
Guidance type
ACRs
ACE Clinical Recommendations (ACRs) are focused, evidence‑based recommendations addressing specific priority clinical questions. Developed using the same methodological rigour as ACE Clinical Guidelines (ACGs), ACRs are more concise and contain less explanatory and “how‑to” information.
Objective: To guide appropriate referral and management of downstream interventions for individuals with Hereditary Breast and Ovarian Cancer (HBOC) syndrome-related pathogenic/likely pathogenic variants (P/LPVs)
Scope: Genetic testing referral, downstream interventions with a focus on hereditary breast cancers and hereditary ovarian cancers
Target audience: These clinical recommendations are relevant to healthcare professionals caring for individuals with HBOC syndrome-related P/LPVs or individuals with personal or family history suggestive of HBOC syndrome
Statement of Intent
The ACE Clinical Recommendations (ACRs) provide concise, evidence-based recommendations as a common national starting point for clinical decision-making, contextualised to Singapore based on best available evidence. The ACRs are not exhaustive of the subject matter and do not replace clinical judgement; responsibility for decisions appropriate to the individual patient remains at all times with the healthcare professional. While ACRs may inform decisions on healthcare policy and services, these are subject to separate processes or considerations. ACRs can highlight implementation considerations where relevant.
Introduction
These recommendations aim to support the management of individuals with HBOC syndrome‑related P/LPVs, and are intended to complement, not replace, clinical judgement in delivering patient-centred care. Clinicians are encouraged to consider the patient’s goals, preferences and concerns, and actively involve the patient in shared decision making to determine the most appropriate management.
When discussing options for genetic testing, surveillance or risk‑reducing interventions with individuals who carry HBOC syndrome‑related P/LPVs, consider the following:
Patient goals: e.g. cancer risk reduction, preservation of quality of life (QoL), minimisation of treatment or follow-up burden
Patient preferences: e.g. preference for conservative management with surveillance versus risk-reducing surgery
Patient concerns: e.g. body image and recovery after surgery, surveillance limitations (e.g. false positive findings, need for additional investigations, overdiagnosis, cumulative radiation exposure, and recall-related anxiety), financial and other psychosocial considerations
Where multiple risk-reducing strategies are being considered, the relative benefits and implications of each should be discussed. Risk-reducing salpingo-oophorectomy (RRSO) has a more established role in reducing ovarian cancer risk and mortality, particularly given the lack of effective intensified ovarian surveillance, whereas decisions regarding risk‑reducing mastectomy (RRM) versus intensified breast surveillance are more dependent on the individual’s breast cancer risk and values.
Recommendation 1
Refer the following individuals for genetic testing to characterise breast cancer-related gene variants:
a) Individuals with a personal history of breast cancer who have risk factors for hereditary breast cancer (see Annex A A1-A5)
b) Individuals with a significant family history of breast cancer, and unknown familial genetic status (see B1-B2)
c) First-degree biological relatives of an individual who carries a pathogenic/likely pathogenic variant (P/LPV) in a breast cancer susceptibility gene; or consider referring second-degree biological relatives if the first-degree relative is unavailable^ (see C1)
Recommendation remarks:
Please refer to Annex A (opens in new tab) for details of the population groups and indications for genetic testing to characterise breast cancer-related gene variants.
Recommendation 2
Refer the following individuals for genetic testing to characterise ovarian cancer-related gene variants:
a) Individuals with a personal history of ovarian cancer, which includes those with epithelial ovarian, fallopian tube or peritoneal cancer (see Annex B A1-A3)
b) Individuals with a significant family history of ovarian cancer, and unknown familial genetic status (see B1-B2)
c) First-degree biological relatives of an individual who carries P/LPV in an ovarian cancer susceptibility gene; or consider referring second-degree biological relatives if the first-degree relative is unavailable^ (see C1)
Recommendation remarks:
Please refer to Annex B (opens in new tab) for details of the population groups and indications for genetic testing to characterise ovarian cancer-related gene variants.
Recommendation 3
Discuss risk-reducing strategies with individuals at elevated risk of breast cancer, and provide access to genetic counselling prior to any surgical decision:
a) For females with high-risk P/LPVs, recommend RRM as an option.
b) For females with moderate-risk P/LPVs and a substantially elevated individual breast cancer risk based on significant family history, reserve recommending RRM as an option.
c) For males with high- or moderate-risk P/LPVs, do not recommend RRM.
Recommendation remarks:
Risk-reducing strategies for breast cancer include RRM, intensified surveillance, and chemoprevention. Decision should be guided by shared decision-making, considering individualised breast cancer risk (using validated risk models where appropriate), age, family history, comorbidities, and patient values and preferences. Counselling on RRM should include degree of breast cancer risk reduction, reconstruction options, procedural risks, and potential impact on QoL.
Chemoprevention and lifestyle modification is beyond the current ACRs’ scope and will be discussed in subsequent guidance.
Refer to Annex C (opens in new tab) for details on P/LPVs categorised under high or moderate risk.
Individuals with HBOC syndrome-related P/LPVs also have increased risks of other malignancies (e.g. prostate, pancreatic and melanoma). Appropriate specialist assessment and counselling regarding these risks are warranted, but beyond the scope of the HBOC ACRs.
Recommendation 4
Offer intensified breast surveillance to females with high- or moderate-risk breast cancer-related P/LPVs who have not undergone RRM, tailoring the surveillance modality based on variant-specific risk, age, breast density and family history.
a) For females with high-risk P/LPVs:
Recommend annual magnetic resonance imaging (MRI) alone for females aged <30 years.
Consider adding mammography to annual MRI for females aged 30-39 years, based on individualised breast cancer risk assessment
Recommend combined annual MRI and mammography for females aged 40-59 years.
Consider annual mammography alone for older females with lower breast density (e.g. ≥60 years).
b) For females with moderate-risk P/LPVs, consider MRI or mammography based on age, variant-specific risk level and other imaging considerations.
c) For males aged ≥50 years with increased breast cancer risk, particularly those with BRCA2 P/LPVs, consider offering annual mammography.
Recommendation remarks:
Intensified surveillance is an appropriate risk-management option for individuals who have not undergone RRM. This includes individuals with HBOC syndrome‑related P/LPVs and a personal history of breast cancer managed with breast‑conserving treatment, where intensified surveillance of the treated and contralateral breasts should be continued, with the surveillance strategy tailored to individual breast cancer risk.
Table A (opens in new tab) provides recommended surveillance strategies to guide clinical discussion; adjustment may be appropriate depending on patient-specific factors, availability of imaging modalities, and specialist radiologist advice if needed.
Recommendation 5
a) Discuss risk-reducing strategies with females who have ovarian cancer-related P/LPVs, taking into account their individualised ovarian cancer risk, preferences and family planning considerations.
b) For females with high-risk ovarian cancer-related P/LPVs, recommend RRSO with timing guided by variant-specific risk, family history and reproductive planning.
Recommendation remarks:
In the absence of effective ovarian cancer surveillance, RRSO plays a key role in ovarian cancer risk reduction. Discussion and counselling regarding RRSO should begin before the suggested age of surgery (Table B) (opens in new tab) and include discussion of timing in relation to family planning as well as potential harms such as surgical menopause.
Chemoprevention, lifestyle modification and aspects of menopausal care are beyond the current ACRs’ scope and will be discussed where relevant in subsequent guidance.
Please refer to Annex C (opens in new tab) for details on the P/LPVs categorised under high‑ or moderate‑risk.
These ACRs have been reviewed and endorsed by Academy of Medicine Singapore (Chapter of Family Medicine Physicians; Chapter of General Physicians, CPS; College of Radiologists, Singapore; College of Surgeons, Singapore; Chapter of Genomic Medicine; Chapter of Medical Oncologists; and College of Obstetricians and Gynaecologists, Singapore) and College of Family Physicians Singapore.
Expert Group
Chairpersons
Prof William Hwang, Medical Oncology (NCCS)
Dr Goh Khean Teik, Ministry of Health Singapore
Members
Dr Chan Ching Wan, General Surgery (Breast) (Solis Breast)
Clin Asst Prof Rose Fok Wai Yee, Family Medicine (NCCS)
A/Prof Mikael Hartman, General Surgery (Breast) (NCIS)
Dr Valerie Heong Yue Ming, Medical Oncology (TTSH)
Dr Lee Yien Sien, Diagnostic Radiology (KKH)
Ms Li Shao-Tzu, Genetic Counselling (NCCS)
Dr Joline Lim, Medical Oncology (Curie Oncology)
Dr Ravichandran Nadarajah, Gynaecologic Oncology (KKH/SGH)
A/Prof Joanne Ngeow, Medical Oncology (NCCS)
Ms Ong Pei Yi, Genetic Counselling (NCIS)
Adj A/Prof Samuel Ow, Medical Oncology (NCIS)
Dr Felicity Jane Pool, Diagnostic Radiology (NUH)
Clin Assoc Prof Rukshini Puvanendran, Family Medicine (KKH)
Clin Asst Prof Sim Yirong, General Surgery (Breast) (NCCS)
A/Prof Tan Ern Yu, General Surgery (Breast) (TTSH)
Ms Tay Li Hui, Nursing (TTSH)
Dr Pearl Tong, Gynaecologic Oncology (NCIS)
Dr Wong Chiung Ing, Medical Oncology (Parkway Cancer Centre)
Dr Wong Wai Loong, Gynaecologic Oncology (STO+G Women’s Health)
ACRs Annexes
Annex C: Absolute risk for breast and ovarian cancers [PDF] (opens in new tab)
ACRs Expert Group details
HBOC Syndrome ACRs EG Composition and other details (Nov 2026) [PDF] (opens in new tab)
ACRs EtR framework
The Evidence-to-Recommendation (EtR) framework is a document that outlines the underpinning evidence and rationale for the recommendations in our ACRs. Download the EtR framework below to learn more about factors that have informed the strength of the recommendations, including certainty of evidence, clinical benefit/risk balance, local resource implications, feasibility considerations, patient preferences and values, acceptability and other considerations.
HBOC Syndrome ACRs EtR framework (Nov 2026) [PDF] (opens in new tab)
Other related resources
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