MEDICAL DISCLAIMER: This tool provides estimates based on historical statistical data (SEER database). It does not provide a medical prognosis for any individual. Every patient is unique. Please consult your oncologist for personalized medical advice.
Stage 0 (In Situ)
Stage I (Localized)
Stage II (Early Regional)
Stage III (Late Regional)
Stage IV (Distant/Metastatic)
Under 40
40 – 74
75+
Positive (HR+)
Negative (HR-)
Unknown
Negative (HER2-)
Positive (HER2+)
Unknown
Estimated 5-Year Relative Survival Rate
–%
Based on SEER relative survival statistics adjusted for subtype approximation.
Understanding Breast Cancer Survival Rates
When diagnosed with breast cancer, one of the first questions patients often ask concerns the survival rate. It is crucial to understand that survival rates are statistical averages derived from large groups of people who were diagnosed with cancer years ago. They cannot predict exactly what will happen to any single individual.
This calculator uses data primarily based on the SEER (Surveillance, Epidemiology, and End Results) database, which tracks 5-year relative survival rates. The "relative" survival rate compares women with the same type and stage of breast cancer to women in the overall population.
Key Factors Used in This Calculation
1. Cancer Stage
The stage of the cancer is the most significant factor in determining prognosis:
Localized (Stage I): The cancer is confined to the breast.
Regional (Stage II/III): The cancer has spread to nearby lymph nodes or structures.
Distant (Stage IV): The cancer has spread (metastasized) to distant parts of the body, such as the bones, liver, or lungs.
Impact of Hormone & HER2 Status
Beyond the physical stage, the biology of the tumor plays a massive role in outcomes. Modern medicine allows for targeted therapies based on these markers:
HR+ (Hormone Receptor Positive): These cancers grow in response to estrogen or progesterone. They often grow slower and can be treated with hormone-blocking therapies, generally leading to a better prognosis.
HER2+ (Human Epidermal Growth Factor Receptor 2 Positive): These cancers have high levels of a growth-promoting protein. While they can be aggressive, targeted therapies like trastuzumab (Herceptin) have drastically improved survival rates for this subtype.
Triple Negative (HR-/HER2-): These tumors lack estrogen, progesterone, and HER2 receptors. They are often more aggressive and have fewer targeted therapy options, relying more heavily on chemotherapy.
Why "5-Year" Survival?
Doctors often use the 5-year mark as a standard benchmark for discussing prognosis. However, many women live much longer than 5 years after diagnosis. For early-stage breast cancer, the 5-year relative survival rate is close to 100%, meaning nearly all women diagnosed at this stage are as likely to live for at least 5 years as women without cancer.
Important Considerations
Statistics do not account for individual health factors, access to care, or the latest treatment advances. Data from 5 years ago may not reflect the efficacy of new drugs approved recently. Always rely on your medical team for your personal prognosis.
function calculateSurvival() {
// Get input values
var stage = document.getElementById("cancerStage").value;
var age = document.getElementById("ageRange").value;
var hr = document.getElementById("hrStatus").value;
var her2 = document.getElementById("her2Status").value;
// Base Survival Rates (Approximate SEER Data by Stage)
// Stage 0/1: ~99%, Stage 2: ~93%, Stage 3: ~72%, Stage 4: ~22-30%
var baseRate = 0;
if (stage === "0" || stage === "1") {
baseRate = 99;
} else if (stage === "2") {
baseRate = 93;
} else if (stage === "3") {
baseRate = 72; // Combined regional average is often cited as 86%, but Stage 3 specifically is lower
} else if (stage === "4") {
baseRate = 29; // SEER distant stage average
}
// Adjustments based on Subtype (HR / HER2)
// These are statistical modifiers to reflect general prognostic trends found in literature (e.g., Triple Negative vs Luminal A)
// Note: These modifiers are simplified estimates for educational purposes.
var modifier = 0;
// Determine Subtype Logic
if (hr === "positive" && her2 === "negative") {
// Luminal A – Generally best prognosis
modifier += 0;
} else if (hr === "positive" && her2 === "positive") {
// Luminal B – Generally good, aggressive but treatable
modifier -= 2;
} else if (hr === "negative" && her2 === "positive") {
// HER2 Enriched – Aggressive but treatable
modifier -= 4;
} else if (hr === "negative" && her2 === "negative") {
// Triple Negative – Most aggressive, harder to treat
modifier -= 10;
}
// Apply Modifier (Only apply strictly if stage is not 0, as Stage 0 is nearly 100% regardless)
if (stage !== "0") {
baseRate = baseRate + modifier;
}
// Age Adjustments
// Younger women ( 99) baseRate = 99;
if (baseRate 12) baseRate = 12; // Statistical reality check for metastatic TNBC
}
// Display Result
var resultBox = document.getElementById("resultSection");
var resultText = document.getElementById("survivalResult");
var noteText = document.getElementById("survivalNote");
resultBox.style.display = "block";
resultText.innerHTML = baseRate + "%";
// Dynamic Note based on subtype
var subtypeText = "";
if (hr === "negative" && her2 === "negative") {
subtypeText = "Estimates for Triple Negative subtypes may vary significantly based on response to chemotherapy.";
} else if (her2 === "positive") {
subtypeText = "HER2+ estimates assume access to targeted therapies like trastuzumab.";
} else {
subtypeText = "Rates are averages based on population data.";
}
noteText.innerHTML = "Estimated 5-Year Relative Survival Rate. " + subtypeText;
}