Although breast cancer is the most common cancer in women in the U.S., deaths from it are declining, probably due to earlier detection and treatment. There are many types of breast cancer; however, all of them need adequate treatment in order to have a good outcome.

About Breast Cancer

Breast cancer is the most common cancer in women in the United States, after skin cancer. However, because of earlier detection and more effective treatment plans, the outcome is often positive.

At this time, there are no known measures to prevent breast cancer. However, researchers continue to search out answers and hopefully reduce risk factors.

The following topics are included in this section:

Facts About Breast Cancer

Following are some facts about breast cancer:

Development of Breast Cancer

Breast cancer is a condition where breast cells become abnormal and multiply uncontrollably due to genetic alteration.

How It Starts

Genetic alterations that lead to breast cancer can occur in one of two ways. A person can inherit them from a parent, in which case the person starts life with damaged genetic code in every cell. A person can also develop a genetic alteration later in life due to environmental factors. In this case, the genetic alteration initially affects one cell which becomes malignant over time. That cell then multiplies and all of its descendants will also have the genetic alteration.

Only 5-10% of breast cancers are hereditary; most are caused by environmental factors which are unknown. Most breast cancer occurs in women without a hereditary risk.

How It Grows

With all cancers, normal cells become abnormal and reproduce additional abnormal cells which no longer function as they should. The growing abnormal cells eventually invade the surrounding healthy tissue.

There are different types of breast cancer. Some cancers grow slowly. One cell may divide every 100 days, potentially taking up to 8 years for cells to reproduce enough to form a mass that can be felt or seen on a mammogram.

Other breast cancers are very aggressive. They grow faster and become evident earlier. Aggressive breast cancers are more difficult to treat.

Origins of Breast Cancer

There are two origins for cancer within the breast:

Ductal carcinoma – Begins in the milk ducts
Lobular carcinoma – Begins in the milk lobules where milk is produced.

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Advancement of Breast Cancer

Breast cancer may spread from its site of origin. Following are the terms used to indicate if the cancer has spread or not:

In Situ

This is early stage cancer that is confined to it site of origin. The cancer is in the milk ducts or lobules, but has not invaded the fatty tissue of the breast. It can involve a small or large area of the breast.

Infiltrating

This is more advanced cancer that has spread from its site of origin into the fatty tissue of the breast. From here, the cancer can spread to other areas of the body.

Types of Breast Cancer

There are many different types of breast cancer; however two types account for the majority of cases.

All breast cancers need adequate treatment in order to have a good outcome. The earlier breast cancer is detected, the more likely it is that treatment will be successful. The treatment of cancer involves getting rid of the abnormal or diseased tissue (local control) and protecting the rest of the body (systemic control).

DCIS - Ductal Carcinoma In Situ

DCIS is an early, noninvasive breast cancer that is still contained in the milk duct system. Nearly all women with this type of cancer can be cured.

Surgical removal is necessary, either with a lumpectomy or mastectomy depending upon the extent. Being a very treatable entity, DCIS generally requires a lumpectomy rather than a mastectomy. Lymph nodes may not need to be surgically removed, but radiation may be recommended. Chemotherapy is not usually necessary.

A mammogram is the best way to find DCIS early. A breast MRI may be done to determine the extent of the disease as it is very important to remove all DCIS.

IDC - Infiltrating Ductal Carcinoma

This is the most common breast cancer, accounting for 80% of all diagnosed breast cancers. It may be felt or may only show on a mammogram or ultrasound.

This cancer begins in the milk ducts and breaks through the duct wall and invades the fatty tissue of the breast. From there it can spread to other parts of the body.

When found early and treated adequately, the outcome is usually very good.

ILC - Infiltrating Lobular Carcinoma

This type occurs in about 10-15% of all breast cancers. It starts in the milk lobules instead of the ducts.

With ILC, the cancer cells filter into the surrounding tissue without creating a wall, as seen in Infiltrating Duct Cancer. Consequently, you may feel more of a thickening in an area of your breast, rather than a distinguishable lump. This type of cancer is also harder to detect with a mammogram.

Other Infiltrating Breast Carcinomas

There are other types of breast cancers that account for a small minority of cases:

Types of Premalignant Abnormalities

A mammogram may also identify pre-malignant abnormalities in the breasts. These are not cancer, but indicate that you have a higher likelihood of developing breast cancer. There are two common types of pre-malignant abnormalities:

ADH - Atypical Duct Hyperplasia

ADH is regarded as a pre-cancer because normal cells have abnormal changes.

Women with ADH have a significantly greater likelihood of developing breast cancer. Consequently, surgical removal (through an excisional biopsy) is recommended if significant amounts of atypical cells are found.

LCIS/ALH - Lobular Carcinoma In Situ or Atypical Lobular Hyperplasia

LCIS and ALH are not considered cancers by many experts. However, they are markers that indicate a higher risk of developing breast cancer. They may be indicative of cancer somewhere in either breast - now or at a later time.

A breast MRI is helpful in determining the presence of more cancer. Surgery may be recommended based upon the MRI findings.

Symptoms of Breast Cancer

The most common sign of breast cancer in both men and women is a lump or thickening in the breast. Other signs of breast cancer include: