Breast Care A-Z · Concept · RISKASSESS

Breast cancer risk assessment

also: Tyrer-Cuzick score, IBIS score, BOADICEA, Manchester score, lifetime breast cancer risk

A breast cancer risk assessment uses your family history, personal history, and sometimes genetic testing to estimate your future risk and guide a screening or prevention plan. You may be wondering whether your family history warrants a formal assessment, or you have been referred for one and want to understand what it involves.

Quick answers

How accurate are these tools?

The tools are validated against large patient populations and are reasonably accurate at the group level — they predict the risk well across many patients. For an individual patient, the actual outcome may be higher or lower than the predicted risk; the tool gives a best estimate, not a guarantee. Repeating the assessment over time (as new family information emerges, or as breast density and biopsy history change) keeps the estimate up to date.

Can I do my own assessment online?

Some online versions of Tyrer-Cuzick are available and can give a useful indication. The clinical version takes account of additional factors (verified family-history details, biopsy results, breast density) and produces a more reliable estimate. The output of an online tool is a starting point for a clinical conversation, not a substitute.

What if I am in the moderate-risk category — should I have surgery?

Risk-reducing surgery is generally not offered for moderate-risk patients. The benefit is too small relative to the impact of the operation. Enhanced surveillance and (in some cases) chemoprevention are the standard pathway. If the risk picture changes — for example, a new family member is diagnosed, or genetic testing later reveals a high-risk mutation — the assessment is repeated and the management pathway adjusts.

BREASTORY ENCYCLOPEDIA · PLATE LVI GENETICS · RISK ASSESSMENT breast cancer risk assessment Tyrer–Cuzick model · IBIS · risk stratification structured quantification of individual lifetime breast cancer risk using family history, genetic, reproductive, and hormonal factors to guide surveillance and prevention i FIG 01 Risk Assessment Funnel · Tyrer–Cuzick / IBIS Model i · Family history (pedigree) ii · Reproductive factors (menarche · parity · breastfeeding) Hormonal (HRT / OCP) iii · Genetic (BRCA / PALB2) iv · Breast density (BI-RADS) v · Prior biopsy (ADH / LCIS) IBIS / Tyrer–Cuzick Risk calculation engine Integrates all input domains → lifetime % risk output Low Moderate High Risk stratification output → surveillance & prevention plan Callouts: i=family history ii=reproductive history iii=gene mutation iv=mammographic density v=atypical biopsy NICE Risk Categories Low: <17% lifetime risk Moderate: 17–29% lifetime risk High: >=30% or BRCA / PALB2 / TP53 carrier (NICE NG151) Risk thresholds guide surveillance & chemoprevention Interventions by Category Low → NHS screening age 50–70 Moderate → annual mammogram from age 40 High → annual MRI + mammogram from age 30 Chemoprevention offered at moderate/high risk (tamoxifen / anastrozole) ii FIG 02 Low vs High Risk Management Comparison Feature <17% Lifetime Risk >=30% / Gene Carrier NHS screening Age 50–70 Earlier + supplemental MRI MRI Not offered Annual from age 30 Mammogram 3-yearly age 50–70 Annual from age 30 Chemoprevention Not offered Tamoxifen / anastrozole offered Genetic testing Not indicated BRCA testing indicated RRM Not indicated Discussed RRSO Not indicated Discussed (BRCA2) Psychological support Standard Enhanced Review With GP Specialist genetics clinic iii FIG 03 Risk Factors and Relative Contribution Factor Relative Risk Notes BRCA1 mutation ~10× ~72% lifetime risk BRCA2 mutation ~8× ~69% lifetime risk 1st degree relative <50 ~3× Mother or sister 2+ 1st degree relatives ~4× Higher if bilateral ADH on biopsy ~4× Combined with family history LCIS ~8–10× Risk marker not cancer High mammographic density ~4–6× Large proportion of women Nulliparity ~1.5× Moderate increase Menarche <12 ~1.2× Modest increase iv FIG 04 Clinical Pathway · Risk Assessment to Surveillance 1 Patient concern family history 2 GP referral 3 IBIS Tyrer-Cuzick calculation 4 Risk category assigned 5 Surveillance plan 6 Genetics referral if high-risk Referral pathway follows NICE NG151 and local genetics service thresholds v FIG 05 Key Concepts & Drug Reference Tyrer–Cuzick / IBIS model Multifactorial risk calculator Manchester scoring Family history scoring system BOADICEA model BRCA pathway modelling Tamoxifen Chemoprevention pre-menopausal Anastrozole Chemoprevention post-menopausal Enhanced surveillance MRI + mammogram high-risk vi FIG 06 Key Statistics · Risk Assessment ~15% lifetime risk general population [1] AUC ~0.66 Tyrer-Cuzick discriminatory accuracy [2] ~40% risk reduction with tamoxifen [3] <10% chemoprevention uptake in eligible [4] vii FIG 07 References 1. Cancer Research UK. Breast cancer incidence 2024 2. Brentnall AR et al. Tyrer-Cuzick validation. Breast Cancer Res 2015 3. Fisher B et al. NSABP P-1 tamoxifen trial. JNCI 1998 4. NICE NG101. Early breast cancer 2023 5. NICE NG151. Familial breast cancer 2023 Clinically authored by Dr Fiona Tsang-Wright , FRCS (Gen Surg) GMC 4549831 · ORCID 0000-0003-4801-026X
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Definition
Breast cancer risk assessment is a structured calculation of an individual's lifetime and 10-year risk of breast cancer, based on family history, personal factors, and (where available) genetic information — used to decide whether enhanced surveillance, chemoprevention, or risk-reducing surgery should be offered.

Common questions The questions patients ask first

How accurate are these tools?
The tools are validated against large patient populations and are reasonably accurate at the group level — they predict the risk well across many patients23. For an individual patient, the actual outcome may be higher or lower than the predicted risk; the tool gives a best estimate, not a guarantee. Repeating the assessment over time (as new family information emerges, or as breast density and biopsy history change) keeps the estimate up to date.
Can I do my own assessment online?
Some online versions of Tyrer-Cuzick are available and can give a useful indication. The clinical version takes account of additional factors (verified family-history details, biopsy results, breast density) and produces a more reliable estimate. The output of an online tool is a starting point for a clinical conversation, not a substitute.
What if I am in the moderate-risk category — should I have surgery?
Risk-reducing surgery is generally not offered for moderate-risk patients1. The benefit is too small relative to the impact of the operation. Enhanced surveillance and (in some cases) chemoprevention are the standard pathway. If the risk picture changes — for example, a new family member is diagnosed, or genetic testing later reveals a high-risk mutation — the assessment is repeated and the management pathway adjusts.
Will my insurance cover risk assessment?
Most UK private medical insurers cover specialist family-history assessment. Pre-authorisation is straightforward where there is a documented family-history concern. For genetic testing, insurer policies vary — confirm before booking.

Breast cancer risk assessment is a structured calculation of an individual’s lifetime and 10-year risk of breast cancer, based on family history, personal factors, and (where available) genetic information — used to decide whether enhanced surveillance, chemoprevention, or risk-reducing surgery should be offered.

Risk assessment is the formal step that turns “I have some breast cancer in my family” into a number — and that number is what determines what surveillance and intervention is offered. UK guidelines categorise lifetime risk into average (under ~17%), moderate (17–30%), and high (over ~30%), with each category triggering a different management pathway.

Orientation Why you might be reading about this

You may be considering whether your family history warrants a formal risk assessment, or you have been referred for one and want to understand what it involves. The structured calculations used (Tyrer-Cuzick, BOADICEA, Manchester) can sound technical, but they all do roughly the same thing: convert family pattern and personal factors into a defensible risk estimate. This page explains how they work and what the categories mean.

Related terms: BRCA · Family history · Mammogram · Breast MRI

Risk tools The risk-assessment tools

Several validated tools are used in UK practice. They draw on different data and produce slightly different estimates, which is why family-history clinics often run more than one.

Tyrer-Cuzick (also called IBIS)

The most widely used tool in UK breast practice2. It takes account of:

  • Family history — first- and second-degree relatives with breast or ovarian cancer, ages at diagnosis, and bilateral cases.
  • Personal factors — age, age at first period, age at first birth, age at menopause, hormone replacement therapy, body mass index.
  • Previous breast biopsies showing atypical changes or LCIS.
  • Breast density on mammography (in newer versions).
  • Known genetic mutations in the family.

Output: lifetime breast cancer risk and 10-year risk, with a comparison to population average.

BOADICEA

A more sophisticated tool, developed at Cambridge, used particularly when family history is the dominant factor3. Stronger statistical model for inferring undetected gene mutations from family pattern. Often used by clinical genetics services3.

Manchester score

A simpler scoring system used as a triage tool — particularly useful for deciding whether to offer BRCA gene testing. Based on the family pattern and the types of cancer in relatives.

NICE CG164 categorisation

Whichever tool is used, UK practice categorises the resulting risk using NICE CG164 thresholds1:

Category Lifetime risk Management
Average / population Under ~17% (vs ~11% UK population baseline per NICE CG164) Routine NHS Breast Screening Programme (mammogram every 3 years from 50–70)
Moderate ~17–30% Annual mammograms from age 40–49 (then NHSBSP frequency from 50); MRI is not offered at moderate risk1
High Over ~30%, or known high-risk gene mutation Annual breast MRI from age 30 for BRCA1/BRCA2 carriers (or >30% carrier probability), from age 20 for TP53 carriers, with annual mammography added from age 401. High-risk women without that genetic profile receive enhanced mammographic surveillance rather than MRI. Genetic testing usually offered. Risk-reducing surgery is one of the discussed options.

The process What the assessment process looks like

For a patient referred to a family-history clinic or specialist genetics service, the typical pathway:

  1. Family-history interview — ideally with confirmation of relatives’ diagnoses where possible (a relative with “breast cancer” might turn out to have been ovarian cancer, or vice versa, on closer inquiry).
  2. Personal-factor history — age, hormonal history, biopsy history.
  3. Risk calculation using one or more of the tools above.
  4. Discussion of the result — what the number means, what the implications for management are, what genetic testing might add.
  5. Plan — surveillance schedule, chemoprevention discussion, and (for high-risk patients) a separate appointment to discuss risk-reducing surgery.

The first appointment usually runs 45–60 minutes. For high-risk patients, several follow-up appointments are common before any decision about genetic testing or surgery is made.

Risk categories What changes with each risk category

Average / population risk

NHS Breast Screening Programme is appropriate. No additional intervention is needed1. Most patients referred for risk assessment turn out to be in this category — the assessment itself is the reassurance.

Moderate risk

Annual mammograms from age 40–49 under NICE CG164 (MRI is not offered at moderate risk). Chemoprevention with tamoxifen or aromatase inhibitors is sometimes discussed for women in their 40s and 50s — modest benefit, side-effect trade-offs.

High risk

Annual breast MRI from age 30 for proven or likely BRCA1/BRCA2 carriers (from age 20 for TP53), often with annual mammography added from age 40. MRI is not recommended for high-risk-by-family-history alone below the genetic threshold. Genetic testing usually offered if not already done. Chemoprevention is discussed. Risk-reducing surgery is one of the discussed options — see risk-reducing mastectomy.

A high-risk result does not mean breast cancer is inevitable. It means the risk is elevated enough that the surveillance and intervention choices are different from the general population.

At consultation What to discuss at consultation

For most patients, risk assessment happens with a clinical geneticist or family-history clinic rather than a surgeon. Surgical input becomes relevant once a high-risk result is identified and risk-reducing options are being considered. Conversations to expect:

  • Which tool is being used and what it has produced.
  • What category your risk falls into and what that means.
  • What surveillance is being offered.
  • Whether genetic testing is being recommended, and on whom in the family it is best done first.
  • The longer-term plan — what age ranges trigger different decisions.

Resources Further reading

Sources & guidance

Every figure on this page is anchored to a published source. Tap a number in the text or below to jump to the reference.

  1. guideline National Institute for Health and Care Excellence (NICE). Familial breast cancer: classification, care and managing breast cancer and related risks in people with a family history of breast cancer (CG164). London: NICE. 2013 ;Last updated 2023 https://www.nice.org.uk/guidance/cg164 Cited for: UK risk thresholds (average / moderate ≥17%; high ≥30% lifetime risk); surveillance schedules; chemoprevention discussion; genetic testing criteria.
  2. cohort Tyrer J, Duffy SW, Cuzick J. A breast cancer prediction model incorporating familial and personal risk factors. Statistics in Medicine. 2004 ;23(7):1111–1130 doi:10.1002/sim.1668 Cited for: The Tyrer-Cuzick / IBIS risk model — combines family history, hormonal/reproductive factors, and biopsy history.
  3. cohort Lee A, Mavaddat N, Wilcox AN, et al. BOADICEA: a comprehensive breast cancer risk prediction model incorporating genetic and non-genetic risk factors. Genetics in Medicine. 2019 ;21(8):1708–1718 doi:10.1038/s41436-018-0406-9 Cited for: BOADICEA risk-prediction model used in UK clinical genetics services.
  4. guideline National Institute for Health and Care Excellence. Early and locally advanced breast cancer: diagnosis and management (NG101). London: NICE. 2018 ;Last updated 2024 https://www.nice.org.uk/guidance/ng101 Cited for: UK pathway for surgical and systemic management of breast cancer in patients identified as high-risk through formal assessment.