Article by Amol Shrikhande, MD

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What is cancer?

The human body’s basic building blocks are called cells. Cells normally grow, divide, and die as needed to maintain the health of the body.

Occasionally, the orderly growth and division of cells can be disrupted when the genes which control this process become altered (or mutated) in some way. In this circumstance, new cells can form when not needed and old cells can remain alive when no longer needed.

The mass of cells which results is called a tumor. Tumors can be benign or malignant. Benign tumors do not spread to other parts of the body and rarely are a threat to life. Malignant tumors are called cancer. Cancers can invade and destroy nearby tissue and can spread (or metastasize) to other parts of the body. Since every part of the body is made of cells, cancer can originate from anywhere within the body.

What is breast cancer?

The human breasts are composed of specialized tissue (collections of cells) that secrete milk used to feed infants. Both men and women have breasts, although those of men are generally smaller and do not develop the ability to produce milk. These specialized cells, just like all other cells, can become cancerous if the genes controlling their growth and division become mutated. Breast cancer can then spread (or metastasize) to lymph nodes in the armpit, the lungs, liver, bones, and/or brain.

How common is breast cancer?

In many countries around the world, breast cancer is the most common type of cancer in women aside from skin cancer. In the United States, over 200,000 women per year are newly diagnosed with breast cancer. (Breast cancer is much less common in men.) Statistics on breast cancer in India are harder to acquire as no comprehensive database exists.

Who is at risk for breast cancer?

All women are at risk for developing breast cancer; in the United States, the lifetime risk is 1 in 8. The following have been found to increase the risk of developing breast cancer:

  • Age: Most cases of breast cancer occur in women over the age of 60. Cases occurring before menopause are less common (but clearly possible).
  • Family history: Women with a first degree relative (mother, sister, daughter) with breast cancer are at higher risk, especially if the family member was less than 40 years old at the time of diagnosis. Certain families carry mutations in one or more genes which leave them at extremely high risk of developing breast cancer.
  • Known breast changes: Women who have certain abnormalities of cells in the breast are at higher risk of developing breast cancer at a later date.
  • Estrogen exposure: Estrogen is a natural molecule called a hormone that is found in humans, with women having higher levels than men. Many tissues (groups of cells) such as the breasts rely upon estrogen to tell their genes when to turn on (including the genes which control cell growth and division.) Any circumstance that results in excessive estrogen levels can therefore predispose to breast cancer.
  • Menstrual history: Women who had their first menstrual period before age 12 and/or menopause after age 55 are at increased risk.
  • Reproductive history: The older a woman is when she has her first child, the higher the risk of breast cancer. Women who never had children are at higher risk.
  • Hormone replacement therapy: women who take estrogen pills after menopause to prevent hot flashes and/or bone thinning may be at increased risk.
  • Weight: Postmenopausal women who are overweight or obese are at higher risk of developing breast cancer.
  • Radiation therapy: Women who received radiation to the chest for another reason (such as another cancer) before age 30 are at higher risk.
  • Breast density: Breast tissue can be dense or fatty. Women whose breast tissue is more dense are more likely to develop breast cancer.
  • Physical inactivity: Women who are physically inactive are at higher risk. This association likely exists as physical inactivity predisposes to obesity (see above).
  • Alcohol: Risk increases in proportion to the amount of alcohol consumed.
  • Other potential risk factors such as diet and environmental exposures are under study. Most women with risk factors do NOT develop breast cancer, while many women without any clear risk factors are afflicted. Bumping, bruising, or touching the breast does not cause cancer. Breast cancer is not contagious.

How is breast cancer diagnosed?

Because breast cancer is extremely common, most experts recommend screening for the disease (in other words, checking for the disease before it causes any symptoms.) Screening allows doctors to find breast cancer early (before it has had the chance to spread extensively), therefore improving the chances that treatment (see below) will result in a cure. The following screening tests are commonly used:

1. Mammogram (X-ray of the breasts) – mammograms can sometimes show breast lumps before they can be felt. They can also show microcalcifications (clusters of calcium specks). Lumps and microcalcifications do not necessarily mean that breast cancer is present, but they warrant further investigation with more X-rays (if needed) and a biopsy. A biopsy involves taking a sample of the tissue (collection of cells) in question and examining it under a microscope to see if cancer cells are present.

2. Clinical breast exam – during a clinical breast exam, a doctor examines a woman’s breasts for any evidence of breast cancer. Specifically, a doctor will look for skin rash, dimpling, and differences in breast size. In addition, he or she will feel both breasts, underarms, and collarbone areas for lumps which might suggest cancer. Finally, the nipples may be squeezed to check for any abnormal fluid production.

3. self-exam – women may perform monthly exams on their own breasts to check for any changes.You should ask your doctor about when to start and how often to check for breast cancer. In the United States, the National Cancer Institute recommends mammograms every 1-2 years starting at the age of 40 and every year after the age of 50. The recommendations on how often to have a clinical breast exam and how often to perform a breast self-exam are not as well defined. Breast self-exams are NOT a substitute for mammograms and clinical breast exams.

Breast cancer can also be diagnosed after the onset of symptoms. Common symptoms of breast cancer include:

1. Changes in how the breast and/or nipple feel. Examples include a lump or thickening in or near the breast, lump or thickening in the underarm area, and nipple tenderness.

2. Changes in how the breast and/or nipple look. Examples include a change in the size or shape of the breast and a nipple turned inward into the breast. In addition, the skin of the breast, nipple, or areola (circular area surrounding the nipple) may be scaly, red, or swollen (possibly to the point of exhibiting pitting such that it looks like the skin of an orange).

3. Nipple discharge. Abnormal fluid coming from the nipple can be a symptom of breast cancer.

Although the above symptoms can be from causes other than breast cancer, a woman should see her health care provider for further evaluation if any such symptom arises. Further testing may include a mammogram, a sonogram (ultrasound), and ultimately a biopsy of the area in question. Although breast cancer is usually not painful in its early stages, breast pain should also be evaluated by a health care professional.

What happens after breast cancer is diagnosed?

Not all breast cancer is the same. After a diagnosis of breast cancer is made, further testing is required to determine (a) the exact nature of the cancer cells and (b) the size and extent (or stage) of the disease (stages range from 0 to IV.) This process may include blood tests, X-rays, and CT scans (another form of X-ray testing that provides much more detail than traditional X-rays). If appropriate, surgical removal of the cancer along with the lymph nodes in the armpit is performed. The specimens are then viewed under a microscope.

Breast cancer cells may resemble normal tissue – such cancer cells are called well-differentiated, or low grade. Conversely, the cancer cells may hardly resemble normal breast tissue – such cells are called poorly differentiated, or high grade. (An intermediate grade also exists). High grade tumors are generally more aggressive. Furthermore, breast cancer cells may or may not respond to normal female hormones called estrogen and progesterone. Those that are not responsive to female hormones are generally more aggressive. Finally, overexpression of a specific gene called HER2/neu may indicate a more aggressive tumor.Staging of breast cancer involves determining the size and extent of the tumor. For instance, stage I disease involves a tumor smaller than 2 cm that is localized to the breast with no spread to the lymph nodes or other parts of the body. On the other hand, stage IV disease indicates cancer that has spread (metastasized) to distant parts of the body such as the lung, liver, bones, and/or brain.Based on the exact nature of the cells and the stage of the disease, a physician can offer a treatment plan (see below) and provide a prognosis, or predicted course of the disease. The prognosis can range from complete cure to eventual death from breast cancer related complications.

How is breast cancer treated?

Breast cancer can be treated with surgery, radiation therapy, chemotherapy, hormone therapy, and biological therapy. The choice of treatment depends mostly on the stage of the disease (but also on the nature of the cells.) Many women receive a combination of the possible treatments as directed by an oncologist, or doctor who specializes in cancer care.

Surgery: Unless breast cancer is very advanced at the time of diagnosis, surgery is a major part of the treatment plan. Even in advanced cases, surgery can be offered to relieve pain and other local symptoms. Either part or all of the involved breast is removed. In addition, some or all of the lymph nodes under the armpit are also removed.

Radiation therapy: Radiation therapy uses high energy X-rays or other types of radiation to kill cancer cells. It is given by a highly specialized doctor called a radiation oncologist. Often, radiation therapy is a key component of adjuvant therapy, or treatment given after surgery to improve the chances of a cure.

Chemotherapy: This form of cancer treatment involves drugs which either kill cancer cells or prevent them from growing. These drugs can be given through a vein (intravenously) or orally. As is the case for radiation therapy, chemotherapy often serves as part of adjuvant therapy. On occasion, it is offered as neoadjuvant therapy, or treatment given before surgery to improve the chances of a cure.

Hormone therapy: Since certain types of breast cancer depend on the female hormone estrogen to grow, blocking the action or production of estrogen may be required to effectively treat the cancer.

Biological therapy: This class of therapy involves the administration of highly specific antibodies which recognize specific proteins on breast cancer cells. These agents can then lead to either the death of cancer cells or the prevention of their growth and spread.

The above provides a broad overview. Due to ongoing advances, information is subject to change. For the most up to date knowledge, please consult your healthcare professional.

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