What is Breast Cancer?

Breast cancer is characterized by the development of a malignant tumor in the breast’s cells. This tumor consists of cells that proliferate uncontrollably and can invade surrounding tissues. While breast cancer is predominantly found in women, it can also affect men.

The Normal Breast

Anatomy of the Breast

The breast comprises lobules, which are glands that produce milk, and ducts, which transport the milk to the nipple. Additionally, the breast contains connective tissue, fatty tissue, blood vessels, and lymph vessels. Most breast cancers originate in the cells lining the ducts, although they can also emerge from lobules. Tumors arising from other breast tissues are classified differently, such as sarcomas and lymphomas.

The Lymphatic System

Lymph nodes, small bean-shaped tissues containing immune cells, are connected by lymph vessels that carry a fluid called lymph. The lymphatic system is crucial for the spread of breast cancer, as lymph vessels from the breast transport lymph to nodes under the arm, around the collarbone, and in the chest. Cancer cells can detach from a tumor and travel through these vessels to lymph nodes, increasing the likelihood of spreading to other body parts. The presence of cancer cells in lymph nodes is a key factor in determining treatment plans.

Benign Breast Lumps

Not all breast lumps are cancerous; benign lumps do not invade other tissues and are generally not harmful. However, they can indicate a heightened risk for breast cancer.

Types of Cancer

Carcinoma

This cancer type originates in the lining cells of organs, including the breast.

Adenocarcinoma

Adenocarcinoma begins in glandular tissue responsible for producing specific fluids. It is the most common form of breast cancer, focusing primarily on the ducts and lobules that create breast milk.

Sarcoma

Sarcoma arises from connective, muscle, fat, or vascular tissue and is rarely associated with breast cancer.

Types of Breast Cancer

This section discusses more common breast cancer types, which can sometimes overlap.

Ductal Carcinoma In Situ (DCIS)

DCIS involves abnormal cells growing in a duct’s lining without invading surrounding tissue, making it a non-invasive form of cancer. It can eventually transform into invasive cancer and is often detected through mammograms.

Invasive Ductal Carcinoma (IDC)

IDC is the most prevalent type of breast cancer, where abnormal cells invade breast tissue and potentially reach lymph nodes and other organs.

Invasive Lobular Carcinoma (ILC)

ILC develops in the lobules and also invades breast tissue, extending to lymph nodes and other areas.

Inflammatory Breast Cancer (IBC)

IBC is a rare form that does not typically present with a lump. Instead, it affects the breast’s skin, causing symptoms like redness, warmth, and thickened or pitted skin. Due to its unique presentation, IBC is often more aggressive and harder to detect through standard mammograms.

Breast Cancer Risk Factors

Various factors can increase the likelihood of developing breast cancer, though they do not guarantee its occurrence.

  • Gender: Women are at a significantly higher risk than men.
  • Age: The risk increases with age.
  • Ethnicity: Caucasian women are generally at a higher risk, while African-American women face a greater mortality rate from the disease.
  • Genetics: Inherited mutations, particularly in the BRCA1 and BRCA2 genes, elevate breast cancer risk.
  • Family History: A family history of breast cancer can increase your risk.
  • Medical History: Previous breast cancer increases the likelihood of developing it in the other breast.
  • Breast Density: Higher glandular tissue density correlates with increased risk.
  • Benign Conditions: Non-cancerous lumps can indicate a higher cancer risk.
  • Lobular Carcinoma In Situ (LCIS): This condition involves abnormal cells in lobules and increases breast cancer risk.
  • Menstrual History: Early menstruation or late menopause can elevate risk.
  • Radiation Exposure: Prior radiation treatment in the chest area significantly raises risk.
  • DES Treatment: Taking diethylstilbestrol (DES) during pregnancy can slightly increase risk.
  • Childbearing: Not having children or having them later in life can slightly increase risk, while multiple pregnancies before age 30 may reduce it.
  • Birth Control Use: Hormonal contraceptives may slightly elevate risk, but this decreases after discontinuation.
  • Hormone Therapy: Combined hormone therapy post-menopause can heighten risks.
  • Breastfeeding: Not breastfeeding increases risk, while breastfeeding for 1.5 to 2 years offers protective benefits.
  • Alcohol Consumption: Consumption of alcohol is linked to a higher risk.
  • Obesity: Being overweight post-menopause increases risk.
  • Tobacco Use: Smoking increases risk, particularly in specific demographics.

Symptoms of Breast Cancer

Common symptoms of breast cancer include:

  • A new mass or lump in the breast, which may be painless, tender, soft, or hard.
  • Swelling in the breast.
  • Skin irritation or dimpling.
  • Breast pain.
  • Nipple changes, such as reversal or discharge.
  • Changes in the skin color or texture of the breast or nipple.
  • Swollen lymph nodes in the underarm or collarbone area.

Breast Cancer Screening

Mammograms are recommended for early detection of breast cancer before symptoms arise, improving treatment effectiveness and outcomes. Screening may involve a combination of symptom reviews, physical examinations, and various imaging tests.

Imaging Techniques

  • X-rays: Breasts are compressed between plates to create images, a process that lasts about 20 minutes.
  • Mammograms: These are essential for screening and diagnosing breast cancer.
  • Ultrasound: Utilizes sound waves to create breast images, distinguishing between cysts and tumors.
  • Magnetic Resonance Imaging (MRI): Provides cross-sectional images of the body using radio waves and magnets.

Biopsy Procedures

Biopsies are necessary for confirming breast cancer diagnosis and involve removing tissue from suspicious areas identified through imaging.

  • Lymph Node Biopsy: Tissue samples are taken from swollen lymph nodes to check for cancer.
  • Breast Tissue Biopsy: A needle is used to extract tissue from identified lumps, or surgical removal may be necessary if initial tests are inconclusive.

Lab Examination of Biopsy Tissue

Laboratories analyze biopsy samples to determine cancer presence, type, growth rate, and treatment options. Cancer is graded from one to three, with lower grades indicating less invasive characteristics.

Hormone Receptors and HER2/neu Testing

Breast cancer cells may possess hormone receptors for estrogen and progesterone, influencing treatment options. Additionally, some cancers exhibit high levels of the HER2/neu protein, guiding targeted therapies.

Gene Expression Patterns

Specific gene patterns can predict cancer recurrence and inform future treatments, with tests like Oncotype DX® and MammaPrint® available for some cases.

Testing for the Spread of Breast Cancer

Testing for metastasis typically occurs if there are concerns about cancer spreading, such as symptoms or tumor size.

  • Chest X-ray: Checks for lung involvement.
  • Bones Scan: Detects cancer spread to bones.
  • Computed Tomography (CT) Scan: Provides detailed images of the chest and abdomen.
  • Magnetic Resonance Imaging (MRI): Creates body images using magnets and radio waves.
  • Ultrasound: Evaluates various body parts for cancer spread.
  • Positron Emission Tomography (PET): Identifies cancer hotspots using a radioactive sugar.

Breast Cancer Staging

Staging assesses how far cancer has spread at diagnosis, influencing treatment strategies. The stage ranges from 0 (non-invasive) to IV (advanced), with TNM classification detailing tumor size, lymph node involvement, and metastasis.

Breast Cancer Treatments

Surgery

Surgery aims to remove the primary tumor and may also include lymph node examination. Options include:

  • Breast-Conserving Surgery: Removes part of the breast and involves follow-up radiation.
  • Mastectomy: Involves complete or partial removal of the breast.
  • Lymph Node Surgery: Assesses lymph nodes for cancer.

Radiation Therapy

Radiation employs X-rays or particles to eliminate cancer cells, generally following surgery.

  • External Beam Radiation: Targets cancer externally.
  • Radioactive Pellets: Implanted in the breast area.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells and may affect normal cells, leading to side effects.

Hormone Therapy

For hormone receptor-positive cancers, therapies aim to block estrogen effects or lower hormone levels.

Targeted Therapy

Drugs are designed to target specific genetic changes in cancer cells, typically with fewer side effects.

Bone-Directed Therapy

These treatments address cancer that has spread to the bones, preventing pain and weakness.

Adjuvant and Neoadjuvant Therapy

Adjuvant therapy follows surgery to eradicate remaining cancer cells, while neoadjuvant therapy is administered to shrink tumors pre-surgery.

Follow-Up on Treatment

Post-treatment follow-ups are essential for monitoring health, involving mammograms and MRIs, especially for BRCA mutation carriers. Maintaining a healthy lifestyle is recommended.

Palliative Care

For patients with unresponsive cancer, the focus shifts to comfort and symptom relief rather than curative treatment.

References

  • DeSantis C, Ma J, Bryan L, Jemal A. Breast cancer statistics, 2013. CA Cancer J Clin. 2014;64(1):52-62. doi:10.3322/caac.212032.
  • Downs-Holmes C, Silverman P. Breast cancer: Overview & updates. Nurse Pract. 2011;36(12):20