CanRisk / BOADICEA Breast and Ovarian Risk Calculator
Use this guide to understand when CanRisk/BOADICEA is preferred over simpler breast risk models.
1. What CanRisk / BOADICEA Estimates
CanRisk is the web interface for BOADICEA, the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm. It is intended for healthcare professionals and estimates future cancer risks and pathogenic variant carrier probabilities using detailed information about the person and their family.
The official CanRisk platform calculates breast and ovarian cancer risks using BOADICEA models and can also support prostate cancer risk estimation through CanRisk-Prostate. It presents results in textual and graphical formats to support risk communication. Official tool: CanRisk.
2. Key Inputs in CanRisk / BOADICEA
CanRisk is more data-intensive than simple breast risk calculators. Depending on available information and local workflow, inputs may include:
| Input domain | Examples | Why it matters |
|---|---|---|
| Pedigree and family history | Cancer types, ages at diagnosis, unaffected relatives, bilateral disease, lineage. | Core to estimating inherited susceptibility and carrier probability. |
| Genetic testing | BRCA1, BRCA2, PALB2, CHEK2, ATM, RAD51C, RAD51D, BARD1, BRIP1 and other gene results depending on model/version. | Pathogenic variants can substantially change cancer risk estimates and management implications. |
| Polygenic risk score | Validated PRS information when available through an appropriate clinical pathway. | Can refine risk stratification beyond rare high- and moderate-penetrance variants. |
| Breast density | Mammographic density measures or categories when available. | Density affects both risk prediction and screening performance. |
| Lifestyle, hormonal, and reproductive factors | Menarche, menopause, parity, hormone therapy, body mass index, alcohol, and other model-supported factors. | Adds non-genetic context to inherited-risk estimation. |
Clinical caution: CanRisk outputs are only as reliable as the entered data. A missing paternal history, uncertain age at diagnosis, incomplete genetic test report, or incorrect density input can move the estimate enough to affect screening or prevention recommendations.
3. When CanRisk Is Preferred Over Gail/BCRAT
Use CanRisk/BOADICEA rather than a simpler Gail-style calculator when the clinical question depends on genetics, pedigree detail, or combined breast/ovarian risk:
- Multiple relatives with breast, ovarian, tubal, peritoneal, prostate, or pancreatic cancer patterns suggesting hereditary susceptibility.
- Known pathogenic or likely pathogenic variant in the patient or family.
- Need to estimate carrier probability before genetic testing or to communicate residual familial risk after testing.
- Risk-reducing mastectomy, risk-reducing salpingo-oophorectomy, MRI screening, or chemoprevention discussions where genetics and family history are central.
- Clinical pathways that explicitly require a BOADICEA/CanRisk estimate.
For simpler population-level invasive breast cancer risk estimates, see the Gail / BCRAT calculator. For model selection across breast risk calculators, see Gail vs Tyrer-Cuzick vs CanRisk.
4. Practical Clinical Workflow
- Confirm the indication. Decide whether the estimate is being used for genetic testing triage, carrier probability, screening, chemoprevention, or surgical prevention counseling.
- Build a pedigree before opening the tool. Capture at least first- and second-degree relatives where possible, including unaffected relatives and ages at diagnosis.
- Separate maternal and paternal lineages. Paternal family history is often under-collected but can be highly relevant.
- Enter genetic test results exactly. Distinguish pathogenic variants, likely pathogenic variants, variants of uncertain significance, and negative tests in affected versus unaffected relatives.
- Record optional risk modifiers consistently. If breast density, PRS, or lifestyle factors are used, document their source and whether they were available for the estimate.
- Translate results into guideline-context decisions. Use local genetics, breast screening, and oncology protocols rather than treating a numerical threshold as an automatic instruction.
5. How CanRisk Compares With Other Breast Risk Models
| Comparison | CanRisk / BOADICEA advantage | When the other tool may be enough |
|---|---|---|
| CanRisk vs Gail/BCRAT | Detailed pedigree, carrier probability, ovarian risk, genetic testing, PRS, and density support. | A straightforward 5-year invasive breast cancer risk estimate for chemoprevention eligibility. |
| CanRisk vs Tyrer-Cuzick/IBIS | More explicit hereditary cancer modeling and carrier probability estimates. | Imaging workflows that specifically use IBIS lifetime risk for MRI eligibility. |
| CanRisk vs BRCA-only thinking | Accounts for moderate-penetrance genes and polygenic/non-genetic factors rather than reducing risk to BRCA1/2 status alone. | Urgent management where a known high-penetrance familial variant already determines the next step. |
6. Limitations and Interpretation Pearls
- Version matters. BOADICEA has evolved as new genes, PRS approaches, density measures, and non-genetic risk factors have been incorporated.
- Data completeness matters. Sparse family history can underestimate hereditary patterns, while selected referral populations can create different expectations than population screening.
- Thresholds are policy-dependent. MRI, chemoprevention, genetic testing, and surgery thresholds differ across health systems and guidelines.
- Risk is not destiny. CanRisk estimates probability; it does not diagnose cancer, guarantee prevention benefit, or determine the correct intervention by itself.
- Specialist interpretation is often appropriate. Complex pedigrees, young-onset cancers, ovarian cancer patterns, or pathogenic variants should generally involve genetics expertise.
7. Frequently Asked Questions
Where should clinicians access CanRisk?
Use the official CanRisk website or a licensed clinical platform that implements the appropriate BOADICEA model version. OncoToolkit does not reproduce the BOADICEA algorithm.
Does CanRisk replace genetic counseling?
No. It can support genetics triage and counseling, but complex results require careful explanation, attention to test limitations, and interpretation within local hereditary cancer pathways.
Can CanRisk be used after a negative genetic test?
Often yes, but the meaning depends on who was tested, what panel was used, whether an affected relative was tested, and whether the result was truly informative for the family. A negative result in an unaffected person may not eliminate familial risk.
Why might two CanRisk estimates differ for the same patient?
Differences can come from model version, pedigree assumptions, breast density entry, PRS availability, genetic test result coding, or updated family history. Document the assumptions used for each estimate.
Use CanRisk for Genetics-Oriented Risk Questions
For simpler breast risk and prevention discussions, pair this guide with Gail/BCRAT and Tyrer-Cuzick/IBIS resources.
Open Breast Cancer ToolsReferences
- CanRisk official tool. Source
- CanRisk Quick Start Guide. Source
- Lee A, et al. BOADICEA: a comprehensive breast cancer risk prediction model incorporating genetic and nongenetic risk factors. Genet Med. 2019;21:1708-1718. Source
- CanRisk model references and publications. Source
- Enhancing BOADICEA cancer risk prediction model to incorporate new data. Source
- Prospective validation of the BOADICEA multifactorial breast cancer risk model. Source
- Joint ABS-UKCGG-CanGene-CanVar consensus regarding clinical use of CanRisk. Br J Cancer. 2024. Source
- NCI Breast Cancer Risk Assessment Tool for Gail/BCRAT comparison. Source