Breast cancer is a disease in which cells in the breast grow uncontrollably. It is the most diagnosed fatal cancer in women and the leading cause of cancer death among women in less developed countries. Men can also get it, but they account for less than one percent of cases.

Breast cancer can begin in different parts of the breast. A breast consists of three main parts: lobules, ducts, and connective tissues. The lobules are milk-producing glands. The ducts are tubes that carry milk to the nipple. The connective tissue (which consists of fibrous and fatty tissue) surrounds and holds the breast together. Most breast cancers begin in the lobules or ducts.

It can spread to other parts of the body through the bloodstream and lymph vessels. This process is called metastases.


The early stage of the disease may not show symptoms. Pain and discomfort are usually not present. Many early breast cancers are identified by mammography.

Signs of breast cancer
Photo credit : medical news today

Some warning signs of breast cancer include:

• A lump or thickening in or near the breast or in the armpit that persists through the menstrual period.

• A mass or lump, which may feel as small as a pea.

• A change in the size, shape, or contour of the breast.

• A blood-stained or clear discharge from the nipple.

• A change in the look or feel of the skin on the breast or nipple (dimpled, puckered, scaly, or inflamed).

• Redness of the skin on the breast or nipple.

• Recent nipple inversion.

• An area that is distinctly different from any other area on either breast.


Types of breast cancer

There are various types of breast cancer. The type depends on which cell in the breast is transformed into cancer.

Some of the most common types include:

In situ cancers

These types have not spread beyond the duct or lobule where they started.

Ductal carcinoma in situ (DCIS). This is ductal carcinoma in its earliest stage (stage 0). In this case, the cancer cells are still in the milk ducts. If not treated, it can spread to other parts of the breast. It is often curable.

Lobular carcinoma in situ (LCIS). This is found only in the lobules, which produce breast milk. It is not true cancer, but having it increases the risk of getting breast cancer later on. It occurs more in women aged 40-50 years. Hence, women with LCIS need to have regular clinical breast examinations and mammograms.

Invasive cancers

These have spread or invaded the surrounding breast tissue. Invasive cancer cells can also spread to other parts of the body.

Invasive ductal carcinoma(IDC). The most common type of breast cancer, accounting for 75% of cases. This cancer begins in the milk ducts, breaks through the wall of the duct, and invades the fatty tissue of the breast.

Invasive lobular carcinoma (ILC). This cancer begins in the lobules but spreads to surrounding tissues or other body parts. It accounts for about 15% of invasive breast cancers.

Other less common types of cancer are papillary carcinoma, tubular carcinoma, mammary paget disease and metaplastic breast cancer.


The cause of breast cancer is not known, although certain factors may increase the risk of developing it. The major factors that increase the risk include being a woman and getting older.

Not all women with risk factors eventually develop it. Some women may get the disease even without any risk factor. Those at risk of getting the disease should contact their doctors on ways they can lower their risk and should carry out regular screening for breast cancer.


Gender. Women are more at risk than men.

Age. Women above 50 years are more likely to get breast cancer than younger women.

Race: African American women are more likely than white women to get breast cancer before menopause.

Personal history of cancer. The odds go up slightly if you have certain benign breast conditions. They go up more sharply if you’ve had it before.

Family history of breast cancer. If a first-degree female relative (mother, sister, or daughter) had breast cancer, the likelihood of getting the disease is four times higher and five times greater in women who have two or more first-degree relatives with breast cancer. This is especially true if they had cancer before menopause or if it affected both breasts. The risk can also increase if a father or brother was diagnosed with the disease.

Family history of ovarian cancer. A history of ovarian cancer in first-degree relatives, especially if it occurs before age 50, has been linked to a 2-fold rise in developing the cancer.

Gene mutations. Changes to two genes, BRCA1 and BRCA2, are responsible for some familiar cases of breast cancer. About 1 woman in 200 has one of these genes. While they increase the risk of getting cancer, they do not mean you definitely will. If a woman has BRCA1 or BRCA2 mutation, she has a 7 in 10 chance of being diagnosed with breast cancer by age 80.

Reproductive factors. The odds increase if:

o Menses start too early

o Menopause occurs at old age (>55yrs)

Previous treatment using radiation therapy. Women who had radiotherapy to the chest or breasts (like for treatment of Hodgkin’s lymphoma) before age 30 have a higher risk of getting it later in life.

Women who took the drug diethylstilbestrol (DES), which was given to some pregnant women between 1940 and 1971 to prevent miscarriage, have a higher risk. Women whose mothers took DES while pregnant with them are also at risk.


Physical inactivity. Physically inactive women have a higher risk of getting breast cancer.

weight and diet. Being overweight /obese after menopause raises the risk.

Alcohol. Persistent drinking increases the risk of the disease.

Reproductive history. Breast cancer odds increase if a woman

o Do not breastfeed.

o Do not have a full-term pregnancy.

o Have never been pregnant.

o First pregnancy occurred at old age.

Taking hormones. Some forms of hormone replacement therapy (those that contain both estrogen and progesterone) taken during menopause can raise the risk for breast cancer when taken for more than five years. Certain oral contraceptives (birth control pills) also have been found to increase the risk.


Stages of breast cancer

Early stage/stage 0. The disease is only in the breast, with no signs that it has spread to the lymph nodes.

Stage I. The cancer is 2cm or less in size and has not spread.

Stage IIA. The tumor is:

o Less than 2cm across, with underarm lymph node involvement.

o Greater than 2 but less than 5cm across, without lymph node involvement.

Stage IIB. A tumor that is:

o Greater than 5cm across, without underarm lymph node involvement

o Greater than 2 but less than 5cm across, with lymph node involvement.

Stage IIIA or locally advanced breast cancer:

o A tumor greater than 5cm that has spread to the lymph nodes under the arm or near the breastbone.

o Any size tumor with cancerous lymph nodes that stick to one another or nearby tissue.

Stage IIIB. A tumor of any size that has spread to the skin or chest wall.

Stage IIIC. A tumor of any size that has spread farther and involves more lymph nodes.

Stage IV (metastatic) breast cancer. A tumor, regardless of size, that has spread to sites far away from the breast, such as bones, liver, brain, lungs, or distant lymph nodes.

The diagnosis, available treatment options, prevention and prognosis of breast cancer will be published in the Part II of this article. Please stay tuned.

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