Breast Cancer Types

Understanding Breast Cancer:

Breast cancer happens in the breast tissue. It may be in one or both breasts. It occurs when cells in the breast multiply unusually, forming a group of cancer cells that spread into nearby tissue or travel to other parts.

These cancer cells break away from the original tumor and move through the blood or lymph vessels to other parts of the body. When they spread and start growing in new areas, it is called metastasis.

There are several types of breast cancer. The type of cancer that you have depends on where it begins in the breasts. Also, the way it has spread and grown, as well as certain features, affect the way it behaves. Knowing your specific type helps you decide on the best treatment plan. Not all breast-related conditions are cancers, so you don't have to panic. Among a few types, the most common type of breast cancer is called invasive breast cancer. In this type, the cancer has spread from where it started in the milk ducts into nearby breast tissue.

What Are the Types of Breast Cancer?

There are different types of breast cancer. These types can be invasive and non-invasive. They are as follows:

Invasive Type of Breast Cancer:

1. Invasive Ductal Carcinoma: IDC (invasive ductal carcinoma) is the most common type of breast cancer. This type of cancer starts in the ducts where milk is produced and spreads to nearby areas. The word “invasive” refers to the cancer’s ability to invade or spread beyond its original location. Let’s know more about the types of IDC:

• HER2-Positive: This occurs when the human epidermal growth factor receptor 2 (HER2) protein is overexpressed, leading to rapid cancer cell growth.

• Estrogen Receptor-Positive: Here, the cancer cells grow in response to the hormone estrogen.

• Progesterone Receptor Positive: This cancer occurs when cancer cells grow in response to the progesterone hormone.

• Triple Positive: Here, the cancer cells test positive for estrogen, progesterone, and HER2 receptors.

• Triple-Negative: In this subtype, the cancer cells test negative for estrogen, progesterone, and HER2 receptors. It is the worst type of breast cancer because it makes the diagnosis difficult and cannot be treated if not detected early.

Invasive ductal cancer is diagnosed via mammograms, ultrasound, MRI (magnetic resonance imaging), and biopsy to confirm the presence and cancer type. Treatment involves surgery, radiation therapy, chemotherapy, hormonal therapy, and targeted cell therapy.

2. Invasive Lobular Carcinoma: ILC (invasive lobular carcinoma) is the second most common type of breast cancer. It starts in the milk-producing glands (lobules) and moves to other areas and body parts. Unlike other breast cancers that form a lump, ILC grows in straight lines, making it harder to detect. This leads to a delay in diagnosis, as ILC is not present with a palpable mass. Various signs of ILC are a hard area in the breast or underarm, changes in the breast size and shape, dimpling of breast skin, and nipple discharge.

ILC is diagnosed using an MRI (magnetic resonance imaging) scan, and treatment options are tumor removal or removal of the whole breast (mastectomy). After surgery, radiation, chemo, and hormonal therapies are done.

3. Triple Negative Breast Cancer (TNBC): TNBC is a rare and the worst form of breast cancer. It is characterized by the absence of three key receptors. They are estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2). This makes it difficult to treat as standard therapies like hormone and HER2-targeted treatments are ineffective. It is prevalent in younger women with a BRCA1 gene mutation and Black women.

Its symptoms are a lump in the breast or nipple pain, dimpled skin, nipple discharge, and swollen lymph nodes. It is diagnosed through a combination of mammograms and ultrasounds. A biopsy is done to examine the tissue. Treatment options for TNBC include chemotherapy before and after surgery.

The aggressive nature of TNBC and chemotherapy impacts the patient physically and emotionally. Side effects include fatigue, nausea, hair loss, and emotional stress.

4. Inflammatory Breast Cancer (IBC): IBC is seen as a rare type, but it is aggressive. Unlike other types, IBC lacks a lump and develops rapidly within weeks or months. It generally affects the skin and lymph vessels of the breast, leading to noticeable changes. Because it is inflammatory, it causes redness or rash over a large area of the breast, swelling, pain, and warmth in the breast. The skin texture resembles an orange peel, and the lymph nodes of the arm or collarbone get swollen. Diagnosis depends on clinical or self-breast examination, mammogram, MRI (magnetic resonance imaging), CT (computed tomography), and biopsy of the affected tissue.

Treatment options for IBC are chemotherapy to shrink the tumor before surgery, mastectomy, radiation therapy, immunotherapy, hormonal therapy, and targeted therapy to destroy any remaining cancer cells.

5. Metastatic Breast Cancer (MBC): It develops in two ways: distant recurrence, when cancer returns in another part of the body months or years after initial treatment, or De novo MBC, when cancer is already metastatic during the first diagnosis. Symptoms are based on where the cancer has spread, such as:

• Bones: Fractures, bone pain, or high calcium levels.

• Lungs: Persistent cough, breathing difficulty, and chest discomfort.

• Liver: Jaundice, abdominal pain, or nausea.

• Brain: Headaches, vision changes, or seizures.

MBC is diagnosed by imaging tests and biopsies.

6. Male Breast Cancer: Begins with the growth of malignant cells in the breast tissue. Though men have less breast tissue than women, they still develop breast cancer. The most common type in males is invasive ductal carcinoma, where cancer cells spread from the milk ducts into surrounding breast tissue. Signs and symptoms that men should watch for are a painless lump in and around the breast, breast tenderness, skin changes, nipple discharge, and nipple retraction (turning inward).

Non-invasive Breast Cancer Types:

1. Ductal Carcinoma in Situ (DCIS): This is a non-invasive type of breast cancer. In this, the abnormal cells are found in the breast duct lining of a woman, but have not gone beyond it. It is considered the starting point of breast cancer and is treatable.

Ductal carcinoma in situ does not show any symptoms and is often spotted during a routine mammogram. If it is left untreated, it will grow and spread to nearby tissue, turning into invasive ductal carcinoma.

2. Lobular Carcinoma in Situ (LCIS): LCIS is a condition where abnormal cells are seen in the lobules (milk-producing glands) of the breast. Its features are the presence of abnormal cells confirmed within the breast lobules. These cells stick to the lobules and do not move to other tissues. This makes LCIS a non-invasive condition. People with LCIS are at risk of getting invasive breast cancer. Therefore, individuals with LCIS should undergo regular breast cancer screening and get treated.

Other Types of Breast Cancer:

1. Medullary Carcinoma: It accounts for about three to five percent of breast cancer cases. Tumors may appear on mammograms but might not present as distinct lumps. They feel like spongy changes in the breast tissue.

2. Tubular Carcinoma: It is very rare. Under a microscope, cells have a tubular structure, which is often related to ductal carcinoma in situ. It is found in women aged 50 and above and responds well to hormone therapy.

3. Mucinous (Colloid Carcinoma): It is seen in one to two percent of breast cancers. Tumors produce mucus and have poorly defined cells.

4. Paget’s Disease: A rare cancer of the breast or nipple, affecting the skin of the nipple and often the areola. It is frequently linked with underlying DCIS or invasive breast cancer. This cancer mimics common skin conditions, which leads to misdiagnosis.

5. Metaplastic Breast Cancer: A rare type accounting for less than one percent. It is aggressive and resembles IDC in imaging.

6. Phyllodes Tumors: These are usually benign, but a small percentage are malignant. Malignant tumors require mastectomy with wide margins to prevent recurrence.

7. Angiosarcoma of the Breast: This cancer type is extremely rare, often seen in individuals with prior extensive chest radiation. It tends to grow and spread rapidly.

What Cells Are Involved in Breast Cancer?

Breast cancer originates from various cell types within the breast, each contributing to different forms of the disease. The most common ones arise from epithelial cells lining the milk ducts and lobules. When cancer starts in the ducts, it is called ductal carcinoma, and when it begins in the lobules, it is lobular cancer. Invasive ductal carcinoma (IDC) is seen often among all breast cancer types, while invasive lobular carcinoma is less common.

Beyond these, breast cancer also develops from the connective tissue or stromal cells, though this is rare. These cells include myofibroblasts and blood vessel cells. Cancers arising from these cells, such as phyllodes tumors and angiosarcomas, are uncommon and account for less than one percent of primary breast cancers.

The tumor microenvironment, formed by various non-cancerous cells, leads to cancer progression and tumor growth. Cancer-related fibroblasts, a type of stromal cell, promote tumor growth by remodeling the extracellular matrix and secreting growth factors that facilitate cancer cells attacking normal cells and spreading across.

Knowing which cells are the culprit helps to detect the cancer type and decide the treatment options for breast cancer.

Breast Cancer Stages:

Breast cancer stages are categorized as follows, depending on the size of the tumor, involvement of the lymphatic vessels, and the amount of its spread to other body parts:

• Stage 0: Non-invasive cancer.

• Stage I: Small localized tumors.

• Stage II: Larger tumors or spread to nearby lymph nodes.

• Stage III: Further spread to lymph nodes or surrounding tissues.

• Stage IV: Cancer has spread to distant organs.

Why Early Detection Matters in Breast Cancer?

Early detection helps in early intervention. It also provides improved treatment outcomes. When breast cancer is identified at a localized stage, the survival rate also improves. It is detected earlier by various methods, such as

• Mammograms: Regular scans of the breast detect tumors even before they are palpable.

• Clinical Breast Exams: It is done by a medical professional who examines your breast by locating and palpating any bumps, lumps, or tumor growths.

• Self-Examination: When you feel pain or notice any lump in your breast.

Conclusion:

Different types of breast cancer exist. Each has its own style of behavior and characteristics. These cancers are classified into different stages of breast cancer. Depending on the stage of breast cancer, the treatment is decided. Learning about the non-invasive, invasive, and rare/aggressive types of breast cancer helps in the correct diagnosis of breast cancer type. Once the cancer is diagnosed, imaging tests like PET-CT (positron emission tomography-computed tomography), MRI, and biopsies are done to confirm the diagnosis and its stage. Determining the heterogeneity of breast cancer helps a doctor offer a personalized plan and care through a multidisciplinary approach.

Key Takeaway From iCliniq:

Every person should know about the different types of breast cancer because some cancers are limited to the breast, whereas others spread across other body parts. The severity of cancer is classified depending on the stages, and then the treatment is planned. Our doctors at iCliniq are professionals who can help you recognize your condition and support you. If you or someone you know has been feeling a lump, pain, or unwanted discharge from the breast, iCliniq doctors can assist you further.