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CIBC Breast Centre

Learn more about breast cancer

Breast cancer: an overview

Breast cancer is the most common type of cancer for women. There are several types.  Treatments will be based on what type has been diagnosed.

Types of Breast Cancer


Refers to a growth of cancerous cells. Cancer begins when normal cells stop working properly and begin to grow abnormally. This process doesn't occur in a day, or in a week, or in a month. It often takes decades or more for a normal cell to start acting like a cancer cell. Cancer cells often show up in the areas of the breast that produce and transport milk, referred to as the lobules and ducts.

Lobular Carcinoma In Situ (LCIS)

LCIS is not an actual cancer. It is considered to be a sign that you may be at a higher risk of developing breast cancer. Most times it is found incidentally in breast biopsies. Both breasts are then at a higher risk of developing breast cancer. Usually LCIS is treated by regularly observing your breasts using a mammogram once a year, and going for a clinical breast exam twice a year. Some women with LCIS consider taking Tamoxifen to prevent breast cancer and some have a bilateral prophylactic mastectomy surgery (the preventative removal of both breasts).

Ductal Carcinoma In Situ (DCIS)

This is the earliest stage (stage 0) of breast cancer, when the cancer is confined to the milk ducts. Of all the breast abnormalities that are detected by the Ontario Breast Screening Program (OBSP), 20 per cent are DCIS and 16 per cent are found at follow-up screenings. If the cancer is caught at stage 0, the success of the treatment is nearly 100 per cent. Without treatment, the cancer can get into the surrounding tissues and become a type of invasive breast cancer.

Infiltrating (invasive) Lobular Carcinoma (ILC)

ILC makes up about 10 to 15 per cent of all breast cancers. This type of breast cancer is often difficult to feel or even see on a mammogram due to the particular pattern in which the cancer cells spread. The treatment however, is the same as for other types of breast cancer (see below).

Infiltrating (invasive) Ductal Carcinoma (IDC)

Invasive ductal carcinoma refers to the cancer that has broken through the wall of the milk duct and started to spread into the tissues of the breast. As the cells begin to grow, they begin to create breast lumps that can sometimes be felt on a breast self-exam.

Even though cancer cells have spread in the breast tissue, it does not mean that cancer has spread into other parts of the body (referred to as metastases). However, if IDC is left untreated, it can continue to spread beyond the breast. The first place that breast cancer usually spread is to the lymph nodes in the armpit.

IDC is the most common invasive breast cancer. About 80 per cent of all breast cancers are invasive ductal carcinomas.

Inflammatory Breast Cancer

Inflammatory breast cancer (IBC) is a not a common type of breast cancer. It grows and spreads quickly, even in the beginning stages. Cancer cells begin to block the lymph vessels in the skin. This stops the lymph vessels from being able to remove fluid, bacteria and other waste products from the breast tissue. The breasts can then become inflamed (red and swollen). IBC tends to grow in layers or nests, not like most common types of breast cancers. Symptoms can appear suddenly, including a change in the size or shape of your breast, breasts that are hot or itchy to the touch, a change in the normal colour of your breasts, or a change in texture. The skin can also have a pitted appearance similar to the skin of an orange.

Lobular Carcinoma

Treatment options will vary according to the size of the tumor, lymph node involvement, hormone receptor status, age and menopausal status of the patient.

Breast Cancer Surgery

The following describes different types of surgery procedures.  It also describes some of the preparation procedures that may be part of a breast surgery.

Needle localization

This procedure is performed when a suspicious area (that cannot be felt) is identified on a mammogram or ultrasound and surgery is needed to remove it. After the skin of the breast is frozen with a local anesthetic, a special needle is inserted into the area of concern using mammography or ultrasound guidance. Once the needle is in place, a fine wire is inserted through the middle of the needle. Then, the needle is removed leaving the wire in place. This wire has a hooked tip that holds it in the specific area. The wire is taped to the skin of the breast and a mammogram is done to confirm the accuracy of the wire placement.

When your needle localization is completed you will be escorted to another area for any further tests required prior to your surgery.


Surgical Treatment of Ductal Carcinoma in Situ (DCIS)

Breast conservation surgery is used to treat DCIS. The surgery is a group of procedures to remove only a portion of the affected breast. For example, lumpectomy is generally the first step, usually followed by radiation therapy. Lymph nodes are generally not removed since cancer cells will not have spread to other parts of the body.

Sometimes, partial mastectomies or quadrantectomies remove a larger portion of the breast tissue (25 to 50 per cent of the breast) and then radiation treatment is usually given.

Breast conservation surgery takes out the part of the breast with the cancer tumour and a centimetre-wide rim of normal tissue around it. The cancer tumour is then sent off to the pathology lab for analysis. If the pathology report comes back suggesting that cancer cells still remain at the end of the incision (cut) where it was thought only normal tissues exist, the surgeon may have to go back to remove more tissue (a re-excision surgery). Sometimes, a mastectomy (removing the entire breast) is necessary because the area of the breast with DCIS is large compared to the size of the breast. Breast conservation therapy is thought to be as effective as mastectomy surgeries for women with early stages of breast cancer. However, breast conservation techniques may not be possible for women with more advanced stages of breast cancer.

Patients are fully assessed by an interdisciplinary care team and encouraged to discuss their recommended treatment options. A customized individual care plan is made up to meet your needs, and include any linguistic, cultural and/or spiritual requirements.



Lumpectomy is also known as a partial mastectomy, wide excision, wedge excision, segmental mastectomy and quadrantectomy.

The surgery removes the breast lump as well as some of the surrounding tissue. The amount of the lump that is removed is different for everyone, but it is generally anywhere between one and 25 per cent of the breast tissue. The goal of this surgery is to keep the breast looking as normal as possible, while still removing the cancer and providing safe treatment.

Once the tumour is removed it is sent to the pathology lab to confirm whether cancer is present and if so, at what stage the cancer is.

This procedure is most commonly followed by several weeks of external beam radiation therapy. Studies have shown that for most women, a lumpectomy or partial mastectomy plus radiation is just as effective as a mastectomy.


Wire Localized Lumpectomy

When the tumour is not felt on a manual breast examination, the surgeon uses a wire localized lumpectomy to find the exact location of the tumour. Before the surgery, a mammogram or ultrasound is done. The radiologist uses the image to help him guide a thin hollow needle into the tumour. The radiologist then places a delicate wire (with a tiny hook at the end) through the hollow needle into the tumour. The hollow needle is then taken out, leaving the tiny hook at the end of the wire into the tumour. This helps the surgeon know where the tumour is and the area around it that needs to be taken out during surgery.


Lymphatic System

The purpose of the lymphatic system is to serve as the “sewage” system for cellular waste in the body. Tiny lymph vessels exist in every organ and tissue in the body. The lymphatic system goes close beside the blood vessels and receives the cell's waste products. This waste is then carried by the lymphatic system and filtered (sorted) through the lymph nodes. The lymph nodes look like small round capsules and can be the size of a pinhead to the size of a grape.

These lymph nodes may serve as places where cancer cells drain to and from the breast tumour. These cells may settle and grow. In order to know how your breast cancer will act in the future, your physician may need to know if any of your cancer cells have traveled to your lymph nodes.



Simple or Total Mastectomy

A simple or total mastectomy involves the surgical removal of the entire breast, but not the lymph nodes from under the arm or the muscle tissue from below the breast.

Modified Radical Mastectomy

This procedure removes all breast tissue including the nipple. Some of the lymph nodes under the arm will also be removed to see whether the cancer has spread.

Radical Mastectomy

This surgery involves the removal of the entire breast, lymph nodes and the chest wall muscles. This surgery is rarely done now since studies have shown that the modified radical mastectomy is just as effective, has fewer side effects and has less disfigurement.

Mastectomy and Immediate Reconstruction

Women who require or desire a mastectomy (because of genetic risk factors) may also consider having reconstruction surgery. Sometimes reconstruction can happen at the same time as a mastectomy. If the mastectomy is done because of an invasive cancer, the patient will have a full discussion with the surgeon and oncologists about the possibility of doing an immediate reconstruction. They will also be referred for a consultation with a plastic surgeon to discuss the risks and benefits of immediate reconstruction.

If an immediate reconstruction is not an option, then after oncological treatment is complete, a consultation with a plastic surgeon will be arranged.  Reconstructive breast surgery following treatment for breast cancer is paid for by the Ontario Health Insurance Plan.

Axillary Dissection

Generally there are three levels of lymph nodes in the underarm. The axillary dissection removes a sample of lymph nodes, usually the first two levels of lymph nodes, from the underarm (axilla) to find out whether cancer has spread. This gives the medical team valuable information on whether you will need more therapy after your surgery. An axillary dissection can be done separately or as part of a lumpectomy or modified radical mastectomy. Samples are then sent to the pathology lab, and the final results come back in about two weeks. Once you have your axillary dissection, you will go home with a drain in place to collect the fluid that would otherwise have built up. After a few days when the amount of fluid is going down, the drain will be removed by a home care nurse.

A condition called lymphedema can also develop in 4 to 5 per cent of women after having an axillary node dissection. Since some of the lymph nodes have been removed, the lymph node system may not be draining enough fluid. As a result, lymphedema can cause your body to hold onto fluid causing your arm or hand to swell. Although the condition is becoming less common, it can happen right after the surgery or even months or years later.

Sentinel Lymph Node Biopsy

The sentinel lymph node biopsy is a new way of seeing if the underarm (axillary) lymph nodes have cancer in them before taking them out. The sentinel node biopsy is done in place of an axillary dissection.

Sentinel node biopsies are done in the Nuclear Medicine Department at St. Michael's Hospital. The surgeon begins by injecting a radioactive dye around the tumour (two to four needles and it feels like a bee sting). The dye is then carried by the lymph system to the lymph node closest to the tumour, called the sentinel node. Once we know where the sentinel node is, a biopsy (small piece of tissue) is taken from it and sent to the pathology department for analysis. If the cancer has spread, this node is the most likely one to have cancer cells in it.

If sentinel node analysis shows that it has cancer cells in it, then more surgery is needed to take out more lymph nodes. If there are no cancer cells, then you will not need to have more lymph nodes removed.

You may notice that your urine turns a blue / green colour for a few days after your procedure. This is normal.

Before and after surgery information tool

The people you might meet on your breast cancer journey: your health care team

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