What is breast cancer?

Breast cancer is a disease in which malignant (cancer) cells form in the tissues of the breast. The disease can also spread to other parts of the body. Signs and symptoms depend on the type and stage of the cancer.

Breast cancer is the most common cancer in women. The disease is more common in older women than younger ones, but it can occur at any age. The risk of developing breast cancer increases as you get older, especially after age 55.

Women who have no family history of breast cancer can still develop it, although this is rare. About 1 out of every 3 women with breast cancer has no known risk factors for developing it. Cancer starts when cells in your body begin to grow out of control. They can take different forms, depending on which type of cell they start in.

What are the cause of breast cancer?

The exact cause of breast cancer is not known. But we know that:

Many factors increase the risk of getting breast cancer

Some factors can reduce your risk of getting breast cancer.

The causes of breast cancer are complex and not yet fully understood. It’s important to remember that many women with breast cancer have no known risk factors.

Factors that increase the risk of getting breast cancer include:

• Age – most cases of breast cancer occur in women aged 50 years or older, although younger women can also get it
• Family history – if you have a close relative (mother, sister or daughter) who has had breast cancer, you are at greater risk. This is because certain genes passed down from your parents may increase your chances of developing the disease.
• Hormone replacement therapy – if you were taking hormone replacement therapy (HRT) when menopause began, this could slightly increase your risk of breast cancer, but only in the first few years after starting HRT.

Who is mainly affected by breast cancer?

Breast cancer is the most common cancer among women worldwide. About 1 in 8 Australian women will be diagnosed with breast cancer by age 85.

About 15,000 women are diagnosed with breast cancer each year in Australia. Breast cancer is the most common cause of death from cancer in Australian women younger than 75 years of age, accounting for about 15% of all deaths from cancer in this age group.

Breast cancers occur mainly in women aged 50 years or older, but they can occur at any age. The risk of developing breast cancer increases with age, as does the risk of dying from it.

Cancer Council estimates that more than 2,000 Australian men will be diagnosed with prostate cancer during 2016-21. These estimates are based on rates calculated using data from 1982-2011 combined with predicted population changes to 2021, assuming that incidence rates remain stable over time (Australian Institute of Health and Welfare 2017).

What age does breast cancer occur?

In the United States, breast cancer is the second most common cancer in women. It accounts for nearly one out of every three cancers in women and is responsible for more deaths than any other cancer in women.

Most breast cancers are diagnosed in women aged 50 or older. More than half of all cases are found in women between the ages of 55 and 64, with the average age at diagnosis being 62.

Breast cancer can occur at any age, but it’s rare in girls younger than 20 years and more common in older women. In general, risk increases with age; however, about 1% of all breast cancers occur before menarche (the first menstrual period).

It also tends to be more common among white women than African American or Hispanic women.

What race is most affected by breast cancer?

The American Cancer Society estimates that for every 100,000 women in the U.S., about 125 will be diagnosed with breast cancer during the course of their lives.

That means an average of about 40,000 new cases occur annually among white women, followed by black women at 29%, Asian women at 12% and Hispanic women at 9%.

Among men, whites account for 65% of all cases of invasive breast cancer. Blacks are next at 14%, followed by Hispanics at 9% and Asians at 8%.

How common is breast cancer?

Breast cancer is one of the most common types of cancer in women. In the United States, about 1 out of 8 women will have breast cancer at some point in their lives.

In 2016, about 252,710 new cases of invasive breast cancer were expected to be diagnosed in women in the U.S., along with 63,410 new cases of DCIS (a non-invasive, or pre-cancerous form). About 40,450 people are expected to die from breast cancer this year.

Breast cancer risk increases with age. The average age at diagnosis is about 64 years old. However, it can occur at any age. It’s rare for girls younger than 20 to develop breast cancer, but it is possible for young girls and teens to get it as well as older women.

What are the types of breast cancer?

• Infiltrating (invasive) ductal carcinoma. Starting in your milk ducts of your breast, this cancer breaks through the wall of your duct and spreads to surrounding breast tissue. Making up about 80% of all cases, this is the most common type of breast cancer.
• Ductal carcinoma in situ. Also called Stage 0 breast cancer, ductal carcinoma in situ is considered by some to be precancerous because the cells haven’t spread beyond your milk ducts. This condition is very treatable. However, prompt care is necessary to prevent the cancer from becoming invasive and spreading to other tissues.
• Infiltrating (invasive) lobular carcinoma. This cancer forms in the lobules of your breast (where breast milk production takes place) and has spread to surrounding breast tissue. It accounts for 10% to 15% of breast cancers.
• Lobular carcinoma in situ is a precancerous condition in which there are abnormal cells in the lobules of your breast. It isn’t a true cancer, but this marker can indicate the potential for breast cancer later on. So, it’s important for women with lobular carcinoma in situ to have regular clinical breast exams and mammograms.
• Triple negative breast cancer (TNBC). Making up about 15% of all cases, triple negative breast cancer is one of the most challenging breast cancers to treat. It’s called triple negative because it doesn’t have three of the markers associated with other types of breast cancer. This makes prognosis and treatment difficult.
• Inflammatory breast cancer. Rare and aggressive, this type of cancer resembles an infection. People with inflammatory breast cancer usually notice redness, swelling, pitting and dimpling of their breast skin. It’s caused by obstructive cancer cells in their skin’s lymph vessels.
• Paget’s disease of the breast. This cancer affects the skin of your nipple and areola (the skin around your nipple).

What are the early signs of breast cancer?

The most common breast cancers are called ductal carcinomas, because they begin in the milk ducts. They can also start in the lobules, or tiny glands that make milk. Ductal carcinoma in situ (DCIS), which means “in place,” is a non-invasive form of breast cancer that has not spread beyond where it started.

Symptoms of breast cancer include:

• A lump or thickening in the breast or underarm area
• A change in size or shape of one breast
• Redness or scaling on the nipple and/or areola (dark area around the nipple)
• Skin dimpling, puckering or itching over the affected area
• Nipple discharge other than breast milk

How is breast cancer diagnosed?

Breast cancer is diagnosed by a doctor who will ask you questions about your medical history and perform a physical exam.

To diagnose breast cancer, the doctor may also:

• Take a tissue sample (biopsy) of the breast mass
• Take a blood test to check for cancer markers in the blood
• Use an imaging test to look inside your breasts

What are the breast cancer stages?

The breast cancer stages are used to describe the extent of a patient’s breast cancer. The stage is one of the most important factors in planning treatment and prognosis.

Stage 0: In situ carcinoma. The cancer cells are not able to spread outside the duct or lobule, but they have invaded its wall.

Stage I: Cancer has invaded some of the surrounding tissue but not reached nearby lymph nodes or other parts of the body.

Stage II: Cancer has spread to lymph nodes under the arm near where the primary tumor was located (regional lymph nodes) or to lymph nodes in other parts of the body (distant metastasis). The tumor size is less than 2 centimeters (about 3/4 inch) or is between 2 and 5 centimeters (about 3/4 inch to about 2 inches).

Stage III: Cancer has spread beyond regional lymph nodes into other parts of the body or has grown larger than 5 centimeters (about 2 inches). It may have also spread to distant areas of the body such as lungs or liver.

How is breast cancer treated?

After you’re diagnosed with breast cancer, your doctor will create a treatment plan to fight the disease. Depending on the type and stage of cancer, treatment may include:

Surgery. Surgery is the most common way to treat breast cancer. It can be done in one of two ways:

Removing all or part of the tumor (lumpectomy) and some healthy tissue around it (called a breast conserving surgery). This is usually done if the cancer has not spread outside the milk ducts or lymph nodes.

Removing all or part of the tumor (mastectomy), as well as all or part of the lymph nodes under your armpit (axillary lymph node dissection) if you have early stage breast cancer that has spread to those lymph nodes. If you have later stage breast cancer, you may have both types of surgery at once.