Breast Cancer Overview: Introduction

In the world today, breast cancer is the second most common type of cancer ever known to women, and also is the second most deadly among them. Like other forms of cancer, breast cancer is when abnormal cells develops inside the breast and grows uncontrollably over a period of time. This form of cells could travel to other parts of the body where they aren’t normally found. And when this happens, they are referred to as Metastatic cancer. There are more than 100,000 cases per year in Nigeria.

Breast cancer usually begins in a small confined area of the breast, most especially the milk producing gland (lobular carcinoma) or the ducts (ductal carcinoma) which moves towards the nipple. This can grow largely in the breast and also spread through the bloodstream into other parts of the individual’s body. The cancer may grow and invade tissue around the breast, such as the skin or chest wall. Different types of breast cancer grow and spread at different rates - some take years to spread beyond the breast, while others grow and spread quickly.

Who Has Breast Cancer?

It is important to note that men also develop breast cancer too, but they account for less than 1% of all breast cancer cases. On average, 1 in 8 women will develop breast cancer in their lifetime (stats by www.cancer.org). About two-thirds of women with breast cancer are 55 or older. Most of the rest are between 35 and 54.

Fortunately, breast cancer is very treatable if detected early. Localized cancer (meaning it hasn’t spread outside your breast) can usually be treated successfully before the cancer spreads. A woman with localized breast cancer is about 99% as likely to live for at least 5 years after diagnosis.

Once the cancer begins to spread, treatment becomes more extensive. It can often control the disease for years. Improved screening tests and treatment options mean about 8 out of 10 women with breast cancer will survive at least 10 years after initial diagnosis.

How Do Breast Cancer Spreads?

Breast cancer can spread when the cancer cells get into the blood or lymph system and are carried to other parts of the body. 

The lymph system is a network of lymph (or lymphatic) vessels found throughout the body that connects lymph nodes (small bean-shaped collections of immune system cells). The clear fluid inside the lymph vessels, called lymph, contains tissue by-products and waste material, as well as immune system cells. The lymph vessels carry lymph fluid away from the breast. In the case of breast cancer, cancer cells can enter those lymph vessels and start to grow in lymph nodes. Most of the lymph vessels of the breast drain into:

• Lymph nodes under the arm (auxiliary nodes)
• Lymph nodes around the collar bone (supraclavicular [above the collar bone] and infraclavicular [below the collar bone] lymph nodes)
• Lymph nodes inside the chest near the breast bone (internal mammary lymph nodes)

Types of Breast Cancer

Understanding the various types of breast cancer common in the female body is dependent whether the abnormal cells hasn’t spread through the bloodstream (in - situ cancer) or they have (i.e. invasive cancers)

1. In - Situ Cancers: These are the type of breast cancer that hasn’t spread pass the lobule or duct where it started, and they include:

• Ductal Carcinoma In situ (DCIS): This is ductal carcinoma in its earliest stage (stage 0). In this case, the disease is still in the milk ducts. But if not treated, it can become invasive. It’s often curable.
• Lobular Carcinoma In situ (LCIS): This is found only in the lobules, which produce breast milk. It isn't a true cancer, but a marker that means an individual is likely to get breast cancer later. Regular breast exams and mammograms are advised for individuals who have this form of in - situ cancer.

2. Invasive Cancers: These are cancers that have spread or invade around the breasts and its environs. These include:

• Invasive or Infiltrating Ductal Carcinoma(IDC): This cancer starts in the milk ducts. It breaks through the wall of the duct and invades the fatty tissue of the breast. It’s the most common form, accounting for 80% of invasive cases.
• Invasive Lobular Carcinoma (ILC):This cancer starts in the lobules but spreads to surrounding tissues or other body parts. It accounts for about 10% of invasive breast cancers. Subtypes of invasive breast cancer include:

• Adenoid Cystic (or adenocystic) Carcinoma: These resemble cells found in the salivary glands and saliva.
• Low-Grade Adenosquamous Carcinoma (a type of metaplastic carcinoma): This rare tumor is usually slow-growing and often mistaken for other types.
• Medullary Carcinoma: The tumors in this rare type are a soft, squishy mass that looks like the medulla in your brain.
• Mucinous Carcinoma: Tumors in this rare type float in a pool of mucin, part of the slippery, slimy stuff that makes up mucus.
• Papillary Carcinoma: Fingerlike projections set these tumors apart. This rare type usually affects women who’ve been through menopause.
• Tubular Carcinoma: The tumors are slow-growing and tube-shaped.

Other less common types include:

• Inflammatory Breast Cancer: This rare type is caused by inflammatory cells in lymph vessels in the skin.
• Paget's Disease of the Nipple: This type affects the areola, the thin skin around your nipple.
• Phyllodes Tumors of the Breast: These rare tumors grow in a leaf like pattern. They grow quickly but rarely spread outside the breast.
• Metastatic Breast Cancer: Cancer that has spread to another body part, like your brain, bones, or lungs.

Breast cancer is treated by a Medical Professional but requires a medical diagnosis and confirmation by Histological examining tissue specimen taken from the breast.

Conclusion

It’s important to understand that most breast lumps are benign and not cancer (malignant). Non-cancerous breast tumors are abnormal growths, but they do not spread outside of the breast. They are not life threatening, but some types of benign breast lumps can increase a woman's risk of getting breast cancer. Any breast lump or change needs to be checked by a health care professional to determine if it is benign or malignant (cancer) and if it might affect one’s future cancer risk.

[Next Week: How Breast Cancer Presents (Signs and Symptoms)]