Breast Cancer

What is breast cancer?

From: MedlinePlus, National Library of Medicine

Breast cancer is a cancer that starts in breast tissue. It happens when cells in the breast change and grow out of control. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumor.

Sometimes the cancer does not spread any further. This is called "in situ." If the cancer spreads outside the breast, the cancer is called "invasive." It may just spread to nearby tissues and lymph nodes. Or the cancer may metastasize (spread to other parts of the body) through the lymph system or the blood.

Breast cancer is the second most common type of cancer in women in the United States. Rarely, it can also affect men.

What are the types of breast cancer?

From: MedlinePlus, National Library of Medicine

There are different types of breast cancer. The types are based on which breast cells turn into cancer. The types include:

• Ductal carcinoma, which begins in the cells of the ducts. This is the most common type.
• Lobular carcinoma, which begins in the lobules. It is more often found in both breasts than other types of breast cancer.
• Inflammatory breast cancer, in which cancer cells block lymph vessels in the skin of the breast. The breast becomes warm, red, and swollen. This is a rare type.
• Paget's disease of the breast, which is a cancer involving the skin of the nipple. It usually also affects the darker skin around the nipple. It is also rare.

What causes breast cancer?

From: MedlinePlus, National Library of Medicine

Breast cancer happens when there are changes in the genetic material (DNA). Often, the exact cause of these genetic changes is unknown.

But sometimes these genetic changes are inherited, meaning that you are born with them. Breast cancer that is caused by inherited genetic changes is called hereditary breast cancer.

There are also certain genetic changes that can raise your risk of breast cancer, including changes in the BRCA1 and BRCA2 genes. These two changes also raise your risk of ovarian and other cancers.

Besides genetics, your lifestyle and the environment can affect your risk of breast cancer.

Who is at risk for breast cancer?

From: MedlinePlus, National Library of Medicine

The factors that raise your risk of breast cancer include:

• Older age
• History of breast cancer or benign (noncancer) breast disease
• Inherited risk of breast cancer, including having BRCA1 and BRCA2 gene changes
• Dense breast tissue
• A reproductive history that leads to more exposure to the estrogen hormone, including: Menstruating at an early age Being at an older age when you first gave birth or never having given birth Starting menopause at a later age
• Taking hormone therapy for meopause
• Radiation therapy to the breast or chest
• Obesity
• Drinking alcohol

What are the signs and symptoms of breast cancer?

From: MedlinePlus, National Library of Medicine

The signs and symptoms of breast cancer include

• A new lump or thickening in or near the breast or in the armpit.
• A change in the size or shape of the breast.
• A dimple or puckering in the skin of the breast. It may look like the skin of an orange.
• A nipple turned inward into the breast.
• Nipple discharge other than breast milk. The discharge might happen suddenly, be bloody, or happen in only one breast.
• Scaly, red, or swollen skin in the nipple area or the breast.
• Pain in any area of the breast.

How is breast cancer diagnosed?

From: MedlinePlus, National Library of Medicine

Your health care provider may use many tools to diagnose breast cancer and figure out which type you have:

If these tests show that you have breast cancer, you will have tests that study the cancer cells. These tests help your provider decide which treatment would be best for you. The tests may include:

Another step is staging the cancer. Staging involves doing tests to find out whether the cancer has spread within the breast or to other parts of the body. The tests may include other diagnostic imaging tests and a sentinel lymph node biopsy. This biopsy is done to see whether the cancer has spread to the lymph nodes.

• A physical exam, including a clinical breast exam (CBE). This involves checking for any lumps or anything else that seems unusual with the breasts and armpits.
• A medical history.
• Imaging tests, such as a mammogram, an ultrasound, or an MRI.
• Breast biopsy.
• Blood chemistry tests, which measure different substances in the blood, including electrolytes, fats, proteins, glucose (sugar), and enzymes. Some of the specific blood chemistry tests include a basic metabolic panel (BMP), a comprehensive metabolic panel (CMP), and an electrolyte panel.
• Genetic tests for genetic changes such in the BRCA and TP53 genes.
• HER2 test. HER2 is a protein involved with cell growth. It is on the outside of all breast cells. If your breast cancer cells have more HER2 than normal, they can grow more quickly and spread to other parts of the body.
• An estrogen and progesterone receptor test. This test measures the amount of estrogen and progesterone (hormones) receptors in cancer tissue. If there are more receptors than normal, the cancer is called estrogen and/or progesterone receptor positive. This type of breast cancer may grow more quickly.

What are the treatments for breast cancer?

From: MedlinePlus, National Library of Medicine

Treatments for breast cancer include:

• Surgery such as A mastectomy, which removes the whole breast A lumpectomy to remove the cancer and some normal tissue around it, but not the breast itself
• Radiation therapy
• Chemotherapy
• Hormone therapy, which blocks cancer cells from getting the hormones they need to grow
• Targeted therapy, which uses drugs or other substances that attack specific cancer cells with less harm to normal cells
• Immunotherapy

Can breast cancer be prevented?

From: MedlinePlus, National Library of Medicine

You may be able to help prevent breast cancer by making healthy lifestyle changes such as:

• Staying at a healthy weight
• Limiting alcohol use
• Getting enough exercise
• Limiting your exposure to estrogen by Breastfeeding your babies if you can Limiting hormone therapy

If you are at high risk, your provider may suggest that you take certain medicines to lower the risk. Some women at very high risk may decide to get a mastectomy (of their healthy breasts) to prevent breast cancer.

It's also important to get regular mammograms. They may be able to identify breast cancer in the early stages, when it is easier to treat.

Genetic causes described in the linked summary

From: MedlinePlus Genetics

Cancers occur when a buildup of mutations in critical genes—those that control cell growth and division or repair damaged DNA—allow cells to grow and divide uncontrollably to form a tumor. In most cases of breast cancer, these genetic changes are acquired during a person's lifetime and are present only in certain cells in the breast. These changes, which are called somatic mutations, are not inherited. Somatic mutations in many different genes have been found in breast cancer cells. Less commonly, gene mutations present in essentially all of the body's cells increase the risk of developing breast cancer. These genetic changes, which are classified as germline mutations, are usually inherited from a parent. In people with germline mutations, changes in other genes, together with environmental and lifestyle factors, also influence whether a person will develop breast cancer.

Some breast cancers that cluster in families are associated with inherited mutations in particular genes, such as BRCA1 or BRCA2. These genes are described as "high penetrance" because they are associated with a high risk of developing breast cancer and ovarian cancer and a moderate risk of developing pancreatic cancer and a type of skin cancer called melanoma in women who have mutations. Men with mutations in these genes also have an increased risk of developing several forms of cancer, including breast cancer, pancreatic cancer, prostate cancer, and melanoma. The proteins produced from the BRCA1 and BRCA2 genes are involved in fixing damaged DNA, which helps to maintain the stability of a cell's genetic information. They are described as tumor suppressors because they help keep cells from growing and dividing too fast or in an uncontrolled way. Mutations in these genes impair DNA repair, allowing potentially damaging mutations to persist in DNA. As these defects accumulate, they can trigger cells to grow and divide without control or order to form a tumor.

A significantly increased risk of breast cancer is also a feature of several rare genetic syndromes. These include Cowden syndrome, which is most often caused by mutations in the PTEN gene; hereditary diffuse gastric cancer, which results from mutations in the CDH1 gene; Li-Fraumeni syndrome, which is usually caused by mutations in the TP53 gene; and Peutz-Jeghers syndrome, which typically results from mutations in the STK11 gene. The proteins produced from these genes act as tumor suppressors. Mutations in any of these genes can allow cells to grow and divide unchecked, leading to the development of a cancerous tumor. Like BRCA1 and BRCA2, these genes are considered "high penetrance" because mutations greatly increase a person's chance of developing cancer. In addition to breast cancer, mutations in these genes increase the risk of several other types of cancer over a person's lifetime. Some of the conditions also include other signs and symptoms, such as the growth of noncancerous (benign) tumors.

Mutations in dozens of other genes have been studied as possible risk factors for breast cancer. These genes are described as "low penetrance" or "moderate penetrance" because changes in each of these genes appear to make only a small or moderate contribution to overall breast cancer risk. Some of these genes provide instructions for making proteins that interact with the proteins produced from the BRCA1 or BRCA2 genes. Others act through different pathways. Researchers suspect that the combined influence of variations in these genes may significantly impact a person's risk of developing breast cancer.

In many families, the genetic changes associated with hereditary breast cancer are unknown. Identifying additional genetic risk factors for breast cancer is an active area of medical research.

Researchers have identified many personal and environmental factors that contribute to a person's risk of developing breast cancer. These factors include sex, age, ethnic background, a history of previous breast cancer, certain changes in breast tissue, and hormonal and reproductive factors. A history of breast cancer in closely related family members is also an important risk factor, particularly if the cancer occurred in early adulthood. In addition, exposure to cancer-causing compounds (carcinogens) can increase the rate at which somatic mutations occur, contributing to a person's risk of developing breast cancer.

Inheritance described in the linked summary

From: MedlinePlus Genetics

Most cases of breast cancer are not caused by inherited genetic factors. These cancers are associated with somatic mutations in breast cells that are acquired during a person's lifetime, and they do not cluster in families.

In hereditary breast cancer, the way that cancer risk is inherited depends on the gene involved. For example, mutations in the BRCA1 and BRCA2 genes are inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to increase a person's chance of developing cancer. Although breast cancer is more common in women than in men, the mutated gene can be inherited from either the mother or the father.

In the other syndromes discussed above, the gene mutations that increase cancer risk also have an autosomal dominant pattern of inheritance. It is important to note that people inherit an increased likelihood of developing cancer, not the disease itself. Not all people who inherit mutations in these genes will ultimately develop cancer.

In many cases of breast cancer that clusters in families, the genetic basis for the disease and the mechanism of inheritance are unclear.

Which doctor should you see?

The suggested department for discussing Breast Cancer is Oncology, with a oncologist and relevant organ specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics; Relevant organ specialist / Surgical Oncology as indicated.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Has the exact tumour type been confirmed, and is staging relevant?
• What is the goal of each proposed treatment option?
• How will side effects, daily function and supportive care be addressed?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.