Types of Breast Cancer
Breast cancer is not a single disease — it includes several types that behave differently and are treated in different ways. Knowing the main types helps you understand what doctors mean when they talk about diagnosis and treatment. Below are the types most commonly discussed, explained in simple language.
Non-invasive (in situ) cancers
These are early forms where abnormal cells remain inside the duct or lobule and haven’t spread into surrounding tissue.
- Ductal carcinoma in situ (DCIS): Cancer cells are inside the milk ducts. DCIS is highly treatable and often removed with surgery; sometimes radiation is recommended to reduce recurrence.
- Lobular carcinoma in situ (LCIS): More of a marker of increased risk than true cancer. Women with LCIS are usually monitored more closely.
Invasive (infiltrating) cancers
These have spread beyond the ducts or lobules into nearby breast tissue and are the most commonly diagnosed types.
- Invasive ductal carcinoma (IDC): The most common type (around 70–80%). IDC starts in the ducts and can form a lump that feels distinct on exam.
- Invasive lobular carcinoma (ILC): Begins in the lobules and may grow in a sheet-like pattern rather than a single lump, sometimes making it harder to detect by touch or mammogram.
Special subtypes that matter
Some subtypes affect treatment choices and outcomes. Two clinically important categories are:
- HER2-positive cancers: These cancers have too much HER2 protein and tend to grow faster. Targeted medicines exist that specifically block HER2 and have greatly improved outcomes.
- Triple-negative breast cancer (TNBC): Lacks estrogen, progesterone, and HER2 receptors. TNBC can be more aggressive and is more common in younger women and some African populations; chemotherapy is a main treatment option, and research is ongoing into new therapies.
Less common but important forms
There are rarer types with distinct signs and urgency:
- Inflammatory breast cancer (IBC): A fast-growing, aggressive form that causes redness, swelling, and skin changes rather than a single lump. It requires urgent care.
- Paget’s disease of the nipple: Starts at the nipple and can cause itching, flaking, or discharge. It’s often linked to an underlying cancer in the breast.
Metastatic breast cancer (stage IV)
When cancer spreads beyond the breast and nearby lymph nodes to organs like bones, liver, lung, or brain, it’s called metastatic. While not curable in many cases, modern treatments can control disease for years and maintain quality of life.
Key point: Tests (like biopsy, hormone receptor tests, HER2 status, and imaging) define the exact type and guide treatment. Two women with “breast cancer” can have very different diagnoses and treatment plans.
What you can do
Learn your family history, do monthly self-checks, and see a clinician if you notice changes. Early detection improves options and outcomes — and knowing the types helps you ask the right questions when you meet a health professional.
