MALLORY  SHOTWELL

Types of Breast Cancer

Below is a detailed breakdown of the most common types of breast cancer, including key features, characteristics, and treatment approaches:

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1. Ductal Carcinoma In Situ (DCIS)

Definition: A non-invasive form of breast cancer that starts in the milk ducts.

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• Key Features:

  • Cancer cells are confined within the milk ducts and have not spread to surrounding tissues.

  • Often considered the earliest form of breast cancer (Stage 0).

  • DCIS is not life-threatening but may progress to invasive breast cancer if left untreated.

• Detection: Often found during routine mammograms due to the presence of calcifications.

• Treatment Options:

  • Lumpectomy or mastectomy (depending on size and location).

  • Radiation therapy may follow surgery to reduce the risk of recurrence.

  • Hormonal therapy (e.g., tamoxifen) if the DCIS is hormone receptor-positive.

2. Invasive Ductal Carcinoma (IDC)
Definition: The most common type of breast cancer, IDC begins in the milk ducts but invades the surrounding breast tissue.
 

• Key Features:

  • Accounts for 80% of all invasive breast cancer cases.

  • Can spread (metastasize) to lymph nodes and distant organs.

  • Typically presents as a lump or thickened area in the breast.

• Detection:

  • Detected via mammogram, ultrasound, or biopsy if a lump is found.

• Treatment Options:

  • Surgery (lumpectomy or mastectomy) to remove the tumor.

  • Chemotherapy, radiation therapy, hormone therapy, or targeted therapy, depending on cancer’s receptor status.​

 

3. Invasive Lobular Carcinoma (ILC)

Definition: Begins in the lobules (milk-producing glands) of the breast and spreads to nearby tissues.

 

• Key Features:

  • ​Second most common invasive breast cancer, accounting for 10-15% of cases.

  • ​May grow in a less defined, "sheet-like" pattern, making it harder to detect on imaging.

  • ​Often hormone receptor-positive, meaning it responds to hormone-blocking treatments.

• Symptoms:

  • ​Thickening or fullness in the breast rather than a distinct lump.

• Treatment Options:

  • ​Surgery (lumpectomy or mastectomy).

  • ​Hormone therapy (e.g., tamoxifen or aromatase inhibitors) if hormone receptor-positive.

  • ​Radiation therapy or chemotherapy, depending on the stage and spread.

4. Triple-Negative Breast Cancer (TNBC)

Definition: A type of breast cancer that does not have estrogen, progesterone, or HER2 receptors.

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• Key Features:

  • ​More aggressive and fast-growing than other types.

  • ​Accounts for 10-15% of breast cancers.

  • ​More common in younger women, African American women, and those with BRCA1 mutations.

• Symptoms:

  • ​Often presents as a palpable lump, but symptoms can vary.

  • ​May spread quickly, requiring early detection and prompt treatment.

• Treatment Options:

  • ​Does not respond to hormone or HER2-targeted therapies.

  • ​Typically treated with chemotherapy, sometimes combined with immunotherapy or PARP inhibitors for patients with genetic mutations.

5. HER2-Positive Breast Cancer

Definition: A type of breast cancer where the tumor cells overproduce the HER2 (human epidermal growth factor receptor 2) protein, which promotes growth.

 

• Key Features:

  • ​Tends to grow and spread more aggressively than HER2-negative cancers.

  • ​Accounts for about 20% of breast cancers.

• Detection:

  • ​Diagnosed using biopsy and tests like IHC (immunohistochemistry) or FISH (fluorescence in situ hybridization) to determine HER2 status.

• Treatment Options:

  • ​Targeted therapies such as trastuzumab (Herceptin) and pertuzumab (Perjeta).

  • Chemotherapy is often combined with HER2-targeted treatments.

  • Surgery and radiation therapy may also be part of the treatment plan.

 

6. Hormone Receptor-Positive Breast Cancer

Definition: Breast cancer that grows in response to hormones like estrogen and/or progesterone.

 

• Key Features:

  • The most common type of breast cancer, comprising approximately 70-80% of all cases.

  • Subtypes include estrogen receptor-positive (ER+) and progesterone receptor-positive (PR+).

  • Typically grows more slowly and has a better prognosis than receptor-negative cancers.

• Treatment Options:

  • Hormone therapy to block estrogen or progesterone (e.g., tamoxifen or aromatase inhibitors).

  • Surgery (lumpectomy or mastectomy) and potentially radiation therapy.

  • Chemotherapy may be used if the cancer is more advanced.

7. Inflammatory Breast Cancer (IBC)

Definition: A rare and aggressive form of breast cancer that blocks lymph vessels in the skin of the breast.

 

• Key Features:

  • Accounts for 1-5% of all breast cancers.

  • Causes swelling, redness, and a "peau d'orange" (orange peel-like) texture on the breast.

  • May not form a distinct lump, making it harder to diagnose.

• Symptoms:

  • Rapid onset of swelling, tenderness, warmth, and skin changes in the breast.

  • Treatment Options:

  • Chemotherapy to shrink the cancer before surgery.

  • Surgery (usually mastectomy) followed by radiation therapy.

  • Targeted therapies if HER2-positive or hormone receptor-positive.

 

8. Metastatic Breast Cancer (MBC)

Definition: Also called Stage IV breast cancer, this occurs when cancer spreads beyond the breast and nearby lymph nodes to distant organs such as the bones, liver, lungs, or brain.

 

• Key Features:

  • Can develop years after initial treatment for early-stage breast cancer.

  • Symptoms vary depending on where the cancer has spread.

• Treatment Goals:

  • Focused on managing symptoms, slowing progression, and improving quality of life.

• Treatment Options:

  • Systemic therapies such as chemotherapy, hormone therapy, targeted therapy, or immunotherapy.

  • Radiation therapy or surgery to manage specific symptoms.