Breast cancer is one of the most common cancers in the world. Every year in the UK there are over 55,000 new cases and the disease claims the lives of 11,500 women. In the United States, it strikes 266,000 people each year and kills 40,000. But what causes it and how can it be treated?

What is breast cancer?

Breast cancer starts from a cancerous cell growing in the lining of a duct or lobule in one of the breasts.

When breast cancer has spread to surrounding breast tissue, it is called “invasive” breast cancer. Some people are diagnosed with “carcinoma in situ,” where no cancerous cells have grown beyond the duct or lobule.

Most cases develop in women over 50, but younger women are sometimes affected. Breast cancer can develop in men although it is rare.

Staging means how big the cancer is and whether it has spread. Stage 1 is the earliest stage and stage 4 means the cancer has spread to another part of the body.

Cancer cells are graded from low, which means slow growth, to high, which means fast growth. High-grade cancers are more likely to come back after being treated for the first time.

What causes breast cancer?

A cancerous tumor starts from an abnormal cell. The exact reason why a cell becomes cancerous is unclear. Something is thought to be damaging or altering certain genes in the cell. This makes the cell abnormal and multiplies “out of control”.

Although breast cancer can develop for no apparent reason, certain risk factors can increase the risk of developing breast cancer, such as genetics.

What are the symptoms of breast cancer?

The usual first symptom is a painless lump in the breast, although most breast lumps are non-cancerous and are fluid-filled cysts, which are benign.

The first place where breast cancer usually spreads is the lymph nodes in the armpit. If this happens, you will develop a swelling or lump in an armpit.

How is breast cancer diagnosed?

• Initial assessment: A doctor examines the breasts and armpits. They can do tests like a mammogram, a special X-ray of the breast tissue that can indicate the possibility of tumors.
• Biopsy: A biopsy is the removal of a small sample of tissue from a part of the body. The sample is then examined under a microscope to look for abnormal cells. The sample can confirm or rule out cancer.

If you are confirmed to have breast cancer, further tests may be needed to see if it has spread. For example, blood tests, liver ultrasound or chest X-ray.

How is breast cancer treated?

Treatment options that may be considered include surgery, chemotherapy, radiation therapy, and hormone therapy. Often a combination of two or more of these treatments is used.

• Surgery: Breast-conserving surgery or removal of the affected breast depending on the size of the tumour.
• Radiation therapy: A treatment that uses high-energy beams of radiation focused on cancerous tissue. This kills cancer cells or stops cancer cells from multiplying. It is mainly used in addition to surgery.
• Chemotherapy: Treatment of cancer using anticancer drugs that kill cancer cells or prevent them from multiplying
• Hormone treatments: Some types of breast cancer are affected by estrogen, a “female” hormone, which can stimulate cancer cells to divide and multiply. Treatments that reduce the level of these hormones or prevent them from working are commonly used in people with breast cancer.

How successful is the treatment?

The outlook is better in those who are diagnosed when the cancer is still small and hasn’t spread. Surgical removal of a tumor at an early stage can then give a good chance of recovery.

Routine mammography offered to women aged 50 to 70 means more breast cancers are being diagnosed and treated at an early stage.

For more information visit breastcancercare.org.uk, breastcancernow.org or www.cancerhelp.org.uk