{
  "id": "breast-cancer-risk",
  "version": "d6b5d2388da3",
  "status": "published",
  "name": "Breast Cancer Risk Calculator",
  "question": "What is my breast cancer risk?",
  "summary": "Estimates a woman’s chance of invasive breast cancer in the next 5 years and by age 90 with the Gail model, as the NCI Breast Cancer Risk Assessment Tool computes it, and the average risk for her age and race.",
  "category": "health",
  "subcategory": "clinical",
  "url": "https://www.acalculator.org/health/breast-cancer-risk-calculator",
  "markdown": "https://www.acalculator.org/health/breast-cancer-risk-calculator.md",
  "kind": "function",
  "method": "Gail model: relative risk from age at first period, age at first birth, first-degree relatives, biopsies, and atypical hyperplasia, times race-specific breast cancer rates and (1 − attributable risk), projected year by year with competing mortality.",
  "assumptions": [
    "For women 35 to 85 with no history of breast cancer, DCIS, LCIS, chest radiation, or a known gene change.",
    "Rates and coefficients are those of the NCI BCRA R package 2.1.2, which the NCI tool uses.",
    "Risks are rounded to 1 decimal, halves up."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "ex": {
        "title": "Past breast cancer, DCIS, LCIS, chest radiation, or a BRCA or other gene change?",
        "description": "Whether you have had breast cancer, DCIS or LCIS, radiation to the chest for Hodgkin lymphoma, or carry a gene change such as BRCA1 or BRCA2. The model does not apply then.",
        "type": "string",
        "enum": [
          "no",
          "yes"
        ]
      },
      "age": {
        "title": "Your age",
        "description": "Your current age in whole years, 35 to 85.",
        "type": "integer",
        "minimum": 35,
        "maximum": 85
      },
      "race": {
        "title": "Race or ethnicity",
        "description": "Race or ethnicity: the model uses different rates and relative risks for each group.",
        "type": "string",
        "enum": [
          "white",
          "black",
          "hispanicUS",
          "hispanicForeign",
          "chinese",
          "japanese",
          "filipino",
          "hawaiian",
          "otherPacific",
          "otherAsian",
          "other"
        ]
      },
      "men": {
        "title": "Age at first period",
        "description": "Your age at your first menstrual period.",
        "type": "string",
        "enum": [
          "ge14",
          "12to13",
          "lt12",
          "unknown"
        ]
      },
      "fb": {
        "title": "Age at first live birth",
        "description": "Your age when your first child was born alive, or no births.",
        "type": "string",
        "enum": [
          "lt20",
          "20to24",
          "25to29",
          "ge30",
          "none",
          "unknown"
        ]
      },
      "rel": {
        "title": "Mother, sisters, or daughters with breast cancer",
        "description": "How many first-degree relatives (mother, sisters, daughters) have had breast cancer.",
        "type": "string",
        "enum": [
          "0",
          "1",
          "2+",
          "unknown"
        ]
      },
      "bx": {
        "title": "Breast biopsies",
        "description": "How many breast biopsies you have had (with a benign result).",
        "type": "string",
        "enum": [
          "0",
          "1",
          "2+",
          "unknown"
        ]
      },
      "ah": {
        "title": "Atypical hyperplasia in a biopsy?",
        "description": "Whether any biopsy showed atypical hyperplasia.",
        "type": "string",
        "enum": [
          "no",
          "yes",
          "unknown"
        ]
      }
    }
  },
  "outputs": {
    "fiveYear": {
      "label": "5-year risk",
      "description": "The chance of invasive breast cancer in the next 5 years, as a percent, to 1 decimal.",
      "format": "percent"
    },
    "fiveYearAverage": {
      "label": "Average 5-year risk, same age and race",
      "description": "The 5-year risk of a woman of the same age and race with no risk factors counted, to 1 decimal.",
      "format": "percent"
    },
    "lifetime": {
      "label": "Risk to age 90",
      "description": "The chance of invasive breast cancer from now to age 90, as a percent, to 1 decimal.",
      "format": "percent"
    },
    "lifetimeAverage": {
      "label": "Average risk to age 90, same age and race",
      "description": "The risk to age 90 of a woman of the same age and race with no risk factors counted, to 1 decimal.",
      "format": "percent"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "ex": "no",
      "race": "white",
      "men": "ge14",
      "fb": "lt20",
      "rel": "0",
      "bx": "0",
      "ah": "no",
      "age": 45
    },
    "outputs": {
      "fiveYear": 0.5,
      "fiveYearAverage": 1,
      "lifetime": 6.4,
      "lifetimeAverage": 11.9
    },
    "text": "The 5-year risk of invasive breast cancer is 0.5% (1% for an average woman of the same age and race)."
  },
  "examples": [
    {
      "given": {
        "ex": "no",
        "age": 45,
        "race": "white",
        "men": "ge14",
        "fb": "lt20",
        "rel": "0",
        "bx": "0"
      },
      "expect": {
        "fiveYear": 0.5,
        "fiveYearAverage": 1,
        "lifetime": 6.4,
        "lifetimeAverage": 11.9
      },
      "source": "NCI BCRA R package 2.1.2 absolute.risk(), run as a literal Python port (docs/progress/WP-89/gail_ref.py): 0.5357%, 0.9668%, 6.4022%, 11.9328%"
    },
    {
      "given": {
        "ex": "no",
        "age": 40,
        "race": "white",
        "men": "12to13",
        "fb": "25to29",
        "rel": "1",
        "bx": "1",
        "ah": "no"
      },
      "expect": {
        "fiveYear": 1.7,
        "fiveYearAverage": 0.6,
        "lifetime": 22.6,
        "lifetimeAverage": 12.4
      },
      "source": "BCRA 2.1.2 port: 1.7295%, 0.5787%, 22.6276%, 12.3682%; relative risks by hand in content.mdx"
    },
    {
      "given": {
        "ex": "no",
        "age": 55,
        "race": "black",
        "men": "lt12",
        "fb": "none",
        "rel": "2+",
        "bx": "2+",
        "ah": "yes"
      },
      "expect": {
        "fiveYear": 7.2,
        "fiveYearAverage": 1.4,
        "lifetime": 34.7,
        "lifetimeAverage": 8.1
      },
      "source": "BCRA 2.1.2 port (CARE coefficients, Gail 2007): 7.2133%, 1.4109%, 34.7442%, 8.0655%"
    },
    {
      "given": {
        "ex": "no",
        "age": 50,
        "race": "hispanicUS",
        "men": "12to13",
        "fb": "ge30",
        "rel": "1",
        "bx": "0"
      },
      "expect": {
        "fiveYear": 1.7,
        "fiveYearAverage": 1.1,
        "lifetime": 12.7,
        "lifetimeAverage": 8.9
      },
      "source": "BCRA 2.1.2 port (Hispanic, US born, Banegas 2017): 1.6643%, 1.1416%, 12.6504%, 8.8545%"
    },
    {
      "given": {
        "ex": "no",
        "age": 60,
        "race": "chinese",
        "men": "ge14",
        "fb": "20to24",
        "rel": "2+",
        "bx": "1",
        "ah": "unknown"
      },
      "expect": {
        "fiveYear": 2.1,
        "fiveYearAverage": 0.8,
        "lifetime": 11.5,
        "lifetimeAverage": 4.7
      },
      "source": "BCRA 2.1.2 port (Asian American, Matsuno 2011): 2.0904%, 0.8268%, 11.4886%, 4.6968%"
    },
    {
      "given": {
        "ex": "no",
        "age": 70,
        "race": "other",
        "men": "unknown",
        "fb": "unknown",
        "rel": "unknown",
        "bx": "unknown"
      },
      "expect": {
        "fiveYear": 1.1,
        "fiveYearAverage": 2.2,
        "lifetime": 3.3,
        "lifetimeAverage": 6.3
      },
      "source": "BCRA 2.1.2 port (unknown answers count as the lowest category): 1.1332%, 2.2109%, 3.3459%, 6.3368%"
    }
  ],
  "sources": [
    "Gail MH, Brinton LA, Byar DP, et al. Projecting individualized probabilities of developing breast cancer for white females who are being examined annually. J Natl Cancer Inst. 1989;81(24):1879-1886. https://doi.org/10.1093/jnci/81.24.1879",
    "Costantino JP, Gail MH, Pee D, et al. Validation studies for models projecting the risk of invasive and total breast cancer incidence. J Natl Cancer Inst. 1999;91(18):1541-1548. https://doi.org/10.1093/jnci/91.18.1541",
    "Gail MH, Costantino JP, Pee D, et al. Projecting individualized absolute invasive breast cancer risk in African American women. J Natl Cancer Inst. 2007;99(23):1782-1792. https://doi.org/10.1093/jnci/djm223",
    "Matsuno RK, Costantino JP, Ziegler RG, et al. Projecting individualized absolute invasive breast cancer risk in Asian and Pacific Islander American women. J Natl Cancer Inst. 2011;103(12):951-961. https://doi.org/10.1093/jnci/djr154",
    "Banegas MP, John EM, Slattery ML, et al. Projecting individualized absolute invasive breast cancer risk in US Hispanic women. J Natl Cancer Inst. 2017;109(2):djw215. https://doi.org/10.1093/jnci/djw215",
    "National Cancer Institute. BCRA: Breast Cancer Risk Assessment, R package version 2.1.2 (absolute.risk.R, relative.risk.R, recode.check.R). https://cran.r-project.org/package=BCRA (retrieved 2026-09-29)",
    "National Cancer Institute. Breast Cancer Risk Assessment Tool. https://bcrisktool.cancer.gov/ (retrieved 2026-09-29)"
  ],
  "related": [],
  "changelog": [
    {
      "date": "2026-09-30",
      "note": "Published after this site's editorial review against the cited sources (no clinician review); the page notices say so. The body text now labels the White rate examples by the right age groups."
    },
    {
      "date": "2026-09-30",
      "note": "The answer sentence prints one percent sign, not two."
    }
  ]
}