Breast cancer is not a single disease—it comes in many forms, each with its own behavior, growth pattern, and treatment approach. Understanding the types of breast cancer helps patients and caregivers make informed decisions about care, treatment, and long-term management.

In this guide, we’ll explore the main categories—invasive and noninvasive breast cancers—along with subtypes based on their location, cell origin, and hormone or genetic characteristics.

Noninvasive (In Situ) Breast Cancer

Noninvasive, or in situ, breast cancer refers to abnormal cells that have not yet spread beyond their original location in the breast ducts or lobules. These early-stage cancers are often discovered during screening mammograms and are highly treatable when detected promptly.

The two main types are ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS).

Ductal Carcinoma In Situ (DCIS)

DCIS is the most common form of noninvasive breast cancer, accounting for about 1 in 5 new breast cancer diagnoses.

It starts in the milk ducts, where abnormal cells form but remain confined within the duct walls.
DCIS isn’t life-threatening, but if untreated, it may progress into invasive ductal carcinoma over time.

Key characteristics

  • Detected through mammograms as microcalcifications

  • Usually doesn’t form a lump

  • Often asymptomatic

Treatment options

  • Lumpectomy (breast-conserving surgery) often followed by radiation

  • Mastectomy in widespread or recurrent cases

  • Hormone therapy (tamoxifen) for hormone receptor–positive DCIS

Early detection of DCIS prevents its transformation into an invasive cancer.

Lobular Carcinoma In Situ (LCIS)

Unlike DCIS, LCIS is not considered a “true cancer” but rather a marker of increased risk for developing invasive cancer in the future—either in the same or opposite breast.

It begins in the lobules (milk-producing glands) and generally doesn’t show up on mammograms.

Key features

  • Typically found incidentally during biopsies

  • Rarely causes symptoms or forms a lump

  • Increases lifetime risk of breast cancer by 7–12 times

Management

  • Close monitoring with mammograms and MRIs

  • Possible preventive medications (tamoxifen or raloxifene)

  • In high-risk cases, prophylactic mastectomy may be considered

Regular screening and vigilance are essential for those diagnosed with LCIS.

Invasive (Infiltrating) Breast Cancer

Invasive breast cancers have spread beyond the milk ducts or lobules into surrounding breast tissue—and potentially to lymph nodes or other parts of the body.
These cancers account for the majority of breast cancer cases and require active treatment.

The two most common types are invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC).

Invasive Ductal Carcinoma (IDC)

IDC represents about 80% of all breast cancer diagnoses.
It begins in the milk ducts but breaks through the duct wall, invading surrounding tissue. Over time, it can spread to lymph nodes and other organs.

Symptoms

  • A firm lump in the breast

  • Changes in breast size or contour

  • Skin dimpling or nipple inversion

Subtypes of IDC

  1. Medullary carcinoma – softer, well-defined borders, often hormone receptor–negative.

  2. Tubular carcinoma – small, slow-growing, and usually low-grade.

  3. Mucinous carcinoma – produces mucus; tends to grow slowly.

  4. Papillary carcinoma – rare, often seen in postmenopausal women.

Treatment

Treatment depends on the tumor’s stage and receptor status but generally involves:

  • Surgery (lumpectomy or mastectomy)

  • Radiation therapy

  • Hormone therapy for ER/PR-positive tumors

  • Targeted therapy for HER2-positive cases

IDC is highly treatable, especially when detected early through screening.

Invasive Lobular Carcinoma (ILC)

ILC makes up about 10–15% of invasive breast cancers.
It begins in the lobules and spreads to nearby tissue in a subtle, diffuse pattern, often making it harder to detect on mammograms.

Distinct characteristics

  • Often feels like thickening rather than a defined lump

  • May cause the breast to appear fuller or firmer

  • Frequently found in both breasts (bilateral involvement)

Treatment

Treatment for ILC mirrors that for IDC, though MRIs are often used for more precise detection. Hormone receptor–positive tumors respond well to endocrine therapy.

Because ILC cells often grow in single-file patterns, early detection can be more challenging—making awareness crucial.

Triple-Negative Breast Cancer (TNBC)

Triple-negative breast cancer accounts for about 10–15% of all breast cancers and is considered one of the more aggressive forms.
It tests negative for estrogen receptors (ER), progesterone receptors (PR), and HER2 protein—hence the name “triple-negative.”

Key facts

  • Grows and spreads faster than most other breast cancers

  • More common in women under 50 and in Black women

  • Does not respond to hormone therapy or HER2-targeted drugs

Treatment

  • Chemotherapy remains the primary treatment

  • Immunotherapy (checkpoint inhibitors) may be added for advanced cases

  • Ongoing research explores targeted treatments for TNBC subtypes

Despite its aggressiveness, early-stage TNBC can respond well to chemotherapy.

HER2-Positive Breast Cancer

In HER2-positive breast cancer, cells produce excessive amounts of the HER2 protein, which promotes cell growth and division.
This type tends to be more aggressive but also highly treatable with modern targeted therapies.

Treatment options

  • Trastuzumab (Herceptin) and pertuzumab (Perjeta) for targeted HER2 blockade

  • Chemotherapy combined with HER2 inhibitors

  • Continued maintenance therapy after surgery

HER2-targeted drugs have revolutionized survival outcomes, turning what was once a difficult subtype into a manageable condition.

Hormone Receptor–Positive Breast Cancer

About two-thirds of all breast cancers are hormone receptor–positive (ER-positive, PR-positive, or both).
This means the cancer cells grow in response to estrogen and/or progesterone.

Treatment

  • Hormone therapy drugs like tamoxifen, aromatase inhibitors, or fulvestrant block hormone effects or reduce hormone production.

  • Long-term hormonal therapy (5–10 years) helps prevent recurrence.

These cancers often grow slowly and respond well to treatment, though they can recur years later if not carefully monitored.

Inflammatory Breast Cancer (IBC)

IBC is a rare but aggressive form of breast cancer, making up about 1–5% of cases.
Rather than forming a lump, it blocks lymph vessels in the skin, leading to redness, swelling, and warmth.

Symptoms

  • Rapid swelling of the breast

  • Red or purplish skin discoloration

  • Pitting or thickened texture (peau d’orange)

  • Pain or tenderness

Treatment

Because IBC spreads quickly, it requires immediate treatment:

  • Chemotherapy first, followed by surgery and radiation

  • Targeted therapy for HER2-positive IBC cases

Early recognition is vital since symptoms can resemble an infection.

Paget’s Disease of the Breast

Paget’s disease is a rare type that begins in the ducts of the nipple and spreads to the areola and surrounding skin.
It accounts for less than 5% of all breast cancers.

Common signs

  • Crusting, itching, or burning around the nipple

  • Flaky or scaly skin

  • Nipple discharge or bleeding

Paget’s disease often coexists with DCIS or invasive cancer elsewhere in the breast.

Treatment

  • Surgery (lumpectomy or mastectomy)

  • Radiation therapy after surgery

  • Hormonal or targeted therapy if underlying cancer is detected

Early recognition of these skin changes is crucial to prevent progression.

Metaplastic Breast Cancer

Metaplastic carcinoma is a rare, aggressive type of invasive breast cancer in which the tumor contains multiple types of cells—some resembling bone, muscle, or skin.

It often tests triple-negative, meaning hormone and HER2 therapies are ineffective.

Treatment

  • Aggressive chemotherapy regimens

  • Immunotherapy or clinical trials for advanced cases

  • Surgery followed by radiation

Because metaplastic breast cancer tends to resist standard treatments, early detection and experimental options are vital.

Phyllodes Tumor

Phyllodes tumors are unusual breast tumors that develop in the connective (stromal) tissue rather than ducts or lobules.
Most are benign, but some can be borderline or malignant.

Features

  • Fast-growing, firm lump

  • Typically not responsive to hormone therapy

  • May recur after surgical removal

Treatment

  • Wide surgical excision with clear margins

  • Mastectomy if the tumor is large or recurrent

  • Radiation in malignant cases

Regular follow-up is essential due to the risk of recurrence.

Male Breast Cancer

Though rare, men can develop breast cancer—making up less than 1% of total cases.
Most male breast cancers are invasive ductal carcinoma, often linked to BRCA2 mutations, liver disease, or hormone imbalance.

Symptoms

  • Lump beneath the nipple

  • Nipple discharge or ulceration

  • Skin dimpling

Men are often diagnosed later due to lack of awareness, leading to more advanced disease. Early detection saves lives regardless of gender.

Secondary (Metastatic) Breast Cancer

When breast cancer spreads beyond the breast and nearby lymph nodes to other organs (bones, lungs, liver, or brain), it becomes metastatic or stage IV breast cancer.

This isn’t a new type but rather the most advanced stage of the disease.

Common symptoms

  • Bone pain or fractures

  • Persistent cough or shortness of breath

  • Abdominal swelling or jaundice

  • Neurological symptoms like headaches or confusion

Treatment goals

While metastatic breast cancer is not curable, modern treatments aim to:

  • Control tumor growth

  • Relieve symptoms

  • Prolong and improve quality of life

Therapies may include chemotherapy, targeted drugs, hormone therapy, immunotherapy, and radiation depending on cancer subtype.

How Doctors Identify the Type

Diagnosis involves analyzing tissue from a biopsy and determining:

  • Histological type (ductal, lobular, etc.)

  • Hormone receptor status (ER/PR-positive or negative)

  • HER2 status

  • Grade and stage (aggressiveness and spread)

This classification helps tailor treatment plans for the best possible outcome.

Key Takeaways

  • Breast cancer is a group of diseases, not a single condition.

  • Understanding whether your cancer is invasive, noninvasive, hormone-positive, or HER2-positive guides effective treatment.

  • Advances in molecular testing and targeted therapies are improving survival rates for nearly all types.

  • Regular screening and self-awareness remain your strongest defense.

Knowledge is empowerment—and awareness can save lives.