. What are the Types of Breast Cancer?

ichhori team

What Are the Types of Breast Cancer?

Breast cancer is categorised by where it starts, how it behaves and whether it has spread. It falls into two main groups: non‑invasive (in situ) and invasive cancers. Within these, there are several subtypes that guide treatment decisions and prognosis.

1. Non‑Invasive (In Situ) Breast Cancer

Non‑invasive cancers are confined to their point of origin and have not spread into surrounding tissue. Two major types are:

  • Ductal carcinoma in situ (DCIS): Cancer cells remain within the milk ducts; stage 0; may progress if untreated. :contentReference[oaicite:3]{index=3}
  • Lobular carcinoma in situ (LCIS): Abnormal cell growth in the milk-producing lobules; usually a marker of increased future risk, not true cancer. :contentReference[oaicite:4]{index=4}

2. Invasive Breast Cancer

These cancers have spread into nearby breast tissue. The most common types include:

  • Invasive ductal carcinoma (IDC): Begins in milk ducts and spreads into breast tissue. Accounts for ~70 – 80 % of invasive cases. :contentReference[oaicite:5]{index=5}
  • Invasive lobular carcinoma (ILC): Originates in lobules; tends to be more diffuse and can affect both breasts. :contentReference[oaicite:6]{index=6}

3. Less-Common Invasive Subtypes

Certain rare forms each have unique features:

  • Inflammatory breast cancer: Aggressive; presents with breast redness, warmth and skin texture changes (peau d’orange). Accounts for 1–5 % of cases and often hormone-receptor negative. :contentReference[oaicite:7]{index=7}
  • Paget's disease of the nipple: Involves nipple skin and areola; often occurs with DCIS or IDC. Accounts for 1–4 % of cases. :contentReference[oaicite:8]{index=8}
  • Phyllodes tumour: Originates in breast stromal (connective) tissue; can be benign or malignant. :contentReference[oaicite:9]{index=9}
  • Angiosarcoma: Rare tumour of blood or lymph vessels; tends to grow rapidly. :contentReference[oaicite:10]{index=10}
  • Other rare types: Medullary, mucinous, tubular and papillary carcinomas—generally better prognosis. :contentReference[oaicite:11]{index=11}

4. Molecular Subtypes

Cancer cells are also classified based on hormone receptor and HER2 status, which informs treatment:

  • Hormone receptor‑positive (HR+): ER+ and/or PR+; treated with hormone-blocking therapies. :contentReference[oaicite:12]{index=12}
  • HER2-positive: Overexpress HER2 protein; may be treated with targeted therapies like trastuzumab. :contentReference[oaicite:13]{index=13}
  • Triple-negative breast cancer (TNBC): Lacks ER, PR and HER2; often aggressive and more common in younger, BRCA1 carriers, and some ethnic groups. Accounts for 15–20 % of cases. :contentReference[oaicite:14]{index=14}

Advanced molecular profiling subdivides TNBC into basal-like, mesenchymal and LAR subtypes—each with distinct behaviour. :contentReference[oaicite:15]{index=15}

5. Other Classifications: Stage & Grade

Staging (0–4) reflects tumour size and spread; stage 0 is in situ, while stage 4 indicates metastasis. :contentReference[oaicite:16]{index=16}

Grading (1–3) gauges how much cancer cells differ from normal cells—higher grades often being more aggressive. :contentReference[oaicite:17]{index=17}

🧭 Why Type, Receptor & Subtype Matter

  • Treatment plans depend heavily on type and molecular subtype.
  • Prognosis varies: for example, IDC has more options, while TNBC, though aggressive, may respond well to chemotherapy.
  • Targeted therapies—hormonal, anti-HER2 or chemo—are selected based on tumour markers.

FAQs About Breast Cancer Types

Q1: What does “in situ” mean?

It means cancer cells remain within their original ducts or lobules and have not spread into nearby breast tissue.

Q2: Is TNBC the same as basal-like?

Often overlapping terms. “Basal-like” is a molecular subset of TNBC identified by genetic profiling. :contentReference[oaicite:18]{index=18}

Q3: Are rare types like mucinous less dangerous?

Yes—many rare subtypes generally grow more slowly and have favourable outcomes. :contentReference[oaicite:19]{index=19}

Q4: Can men get breast cancer?

Yes, though rare (~1 %), men can develop breast cancer—most commonly IDC. :contentReference[oaicite:20]{index=20}

Q5: Why test for ER/PR/HER2?

These markers guide treatment choices—hormone therapies target ER/PR+ tumours, while HER2-targeted drugs help HER2-positive cancers.

Conclusion

Differentiating breast cancer types—non‑invasive vs invasive, special subtypes, hormone/HER2 status, and genetic profiles—is essential for selecting treatment, estimating prognosis, and tailoring patient care. Diagnosis typically involves biopsy, imaging and detailed receptor testing.

For more on breast cancer treatment, symptoms and self‑care, explore our Health section or return to our sitemap for related topics.

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