CIBC Breast Centre

Surgical Oncology

The Surgical Oncology team provides consultation and a variety of treatment options for pre-cancer and cancer diagnoses. Most women with breast cancer will have some type of surgery to remove as much of the cancer as possible. Surgery may also be followed by other treatments such as chemotherapy, hormone therapy or radiation therapy. Hormone and radiation therapy are offered at Princess Margaret Hospital (PMH) and Sunnybrook Hospital.

Surgery may also be performed to:

  • Find out whether the cancer has spread to the lymph nodes under the arm (auxiliary node dissection)
  • Restore a more normal appearance (reconstructive surgery)
  • Relieve symptoms of advanced cancer

Your surgeon will meet with you to discuss the most suitable treatment option for you and your condition.

The most common types of breast cancer surgery are described below.

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. However, if the lesions are big (greater than 5 cm), some experts feel that they may hide microinvasion (small microscopic cancer cells) and recommend taking a small sample of the lymph node to check if there are cancer cells.

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 every one, 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. However, there are many factors that go into making a deciding on which surgery is best for you.

Wire Localized Lumpectomy

When the tumour is not felt on a manual breast examination, the surgeon uses a wire localized lumpectomy technique 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 where they settle. 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. If an immediate reconstruction is not an option, then a consultation with a plastic surgeon will be arranged when all your necessary treatments are completed. 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 node 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. Not having unnecessary lymph nodes removed, may reduce your chance of developing lymphedema .

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

Lobular Carcinoma

About five per cent of malignant invasive breast cancers are lobular. In invasive lobular carcinoma, the tumour grows in the terminal part of the breast lobules where milk is produced.

It often does not show up on mammography and may feel like a thickening in the breast. Lobular cancers are often found in other parts of the breast (multicentric). Treatment options will vary according to the size of the tumour, lymph node involvement, hormone receptor status, age and menopausal status of the patient.