Partial mastectomy (sometimes called lumpectomy) is a breast-conserving operation in which the surgeon removes the tumour together with some of the healthy breast tissue surrounding it.

Women who have this surgery usually:

  • Have a single breast cancer less than 3cm in diameter
  • Have enough breast tissue so that removing surrounding tissue would not leave a misshapen breast, and are medically able to undergo surgery and follow-up radiation therapy.

Partial mastectomy with radiation therapy is often considered the standard therapy for women who meet these criteria. Radiation treatment can be delivered at the same time as surgery ( or daily treatments depending on the cancer size and type.

Women who aren't candidates for partial mastectomy surgery plus radiation include those who:

  • Have had radiation to the same breast for an earlier breast cancer
  • Are pregnant and should avoid radiation, or have multiple breast tumours.

Surgical Procedure

A partial mastectomy surgery is done under general anaesthesia, and usually takes one to two hours. Small metallic clips may be placed inside the breast to mark the area for the radiotherapist to treat afterwards. At the same time as the breast tissue is removed, lymph nodes are often removed and examined, usually by sentinel node biopsy incorporating a separate small incision under the arm.

For a tumour that is not palpable (not obvious or big enough to be felt), a wire is sometimes placed adjacent to it to allow surgeons to locate and remove it safely. This procedure is called Hookwire localisation. (See link in page 5 of radiology section).

You will probably stay one or two nights in hospital.

A mastectomy is an operation that removes the entire breast, and is the treatment of choice for larger tumours or multiple tumours. It is also needed for women in whom it is not safe to have a partial mastectomy, because there is extensive cancer.

A simple mastectomy surgery includes the complete removal of the breast with no removal of lymph nodes. However, these days, mastectomy is usually accompanied by sentinel node biopsy, or axillary dissection.

Surgical Procedure

Breast cancer surgery is done under general anaesthesia and usually takes two to three hours. During the procedure, the surgeon makes an incision, which may extend to the armpit if the lymph nodes are removed, and removes the breast. Usually two drains are left in place, one under the breast wound and the other under the armpit. Mastectomy surgery can be followed by immediate breast reconstruction, which is performed by our plastic surgeon.

Dissolving sutures are used in the wound. You will usually be in hospital one or two nights and go home with one drain in your armpit. Our breast nurse will explain how to manage the drain.

Breast cancer surgery is always accompanied by an examination of one or more of the lymph nodes in the armpit, sometimes referred to as the axilla. If cancer spreads from the breast, it travels to these “sentinel” lymph nodes first.

Knowing if the cancer has spread also helps us to stage it (find out how much cancer there is in the body and where it is located), advise on further treatment and determine your prognosis.

In the past, all women found with a breast tumour had an axillary clearance, where all the lymph nodes in the armpit were removed. But this extensive removal can be associated with more post-operative complications, such as pain, swelling and nerve damage, without any added benefit to the woman. A newer technique – sentinel node biopsy - is now used in a large number of women. This procedure reduces the possible side effects, while still providing the information needed for treatment planning.

What is the sentinel lymph node?

A fine network of vessels drains the breast up to the lymph nodes in the armpit (less commonly, to the sternum). If breast cancer spreads it travels by this pathway. The sentinel lymph node is the “guardian” node, or the first that the cancer will spread to. There are one to four sentinel lymph nodes.

What is a sentinel node biopsy?

A sentinel node biopsy is the removal and examination of these nodes to determine if the breast cancer has spread. A pathologist examines the lymph nodes during surgery - if they do not contain cancer, no further nodes are removed. If the nodes do contain cancer, an axillary dissection - removing more lymph nodes from a wider area – will be performed.

How is the sentinel node located?

Prior to surgery, radioactive fluid is injected into the breast under the areola (dark area around the nipple). The fluid moves through the fine lymphatic vessels up to the lymph nodes in the armpit. During surgery, a radioactive scanner, or probe, is then inserted into a small cut made under the arm, or into the end of the mastectomy wound, to identify the “hot” sentinel nodes, which are removed during surgery. A pathologist examines them to determine if they contain cancer or not.

While you are under anaesthetic, your surgeon may also inject a blue dye and massage it up to the armpit; this can also be used to identify the sentinel nodes.

Not all cancers are suitable for a sentinel node biopsy, and your specialist and nurse will discuss this with you.

What is an axillary dissection?

If your cancer is not suitable for a sentinel node biopsy, an axillary dissection (clearance) will be performed. This usually means 10-20 lymph nodes are removed, from what surgeons describe as level one and level two areas – this denotes how far surgeons go into the surrounding tissue to remove lymph nodes. A plastic drain is left in the armpit after the operation to drain excess fluid. This is well tolerated by most women, and other nodes are left intact to carry out normal lymphatic function.

Any surgery on the lymph nodes under the arm requires a post-operative treatment plan for arm exercises, and women are given information about lymphoedema (chronic swelling) and its prevention.

Oncoplastic surgery combines plastic surgery techniques with breast cancer resection techniques. When a large lumpectomy is required that will leave the breast distorted, the remaining tissue is sculpted to realign the nipple and areola and restore a natural appearance to the breast shape. Sometimes the opposing breast will also be modified to create symmetry.

About 10-15% of patients undergoing lumpectomy may require this. In our NZ environment where breast screening largely picks up smaller tumours, the majority of women can have tissue removed and a smaller cosmetic procedure undertaken where the breast tissue is moved and manipulated easily without the other breast needing any surgery.

At Auckland Breast Centre, we are increasingly adopting the use of neoadjuvant chemotherapy and or targeted therapies prior to surgery to shrink the breast cancer to a size where bigger operations are not required.  This has become the norm in modern overseas practices with an improvement in local control and a requirement for less surgery.

At Auckland Breast Centre to maximise the cancer treatments and cosmesis, we use breast cancer surgeons and plastic surgeons in two teams for the majority of cases that require larger cancer resections (10-15% of cases).  Philosophically, we believe it is important to separate the cancer resection and the breast appearance to the respective specialists, surgery time is reduced with a two surgeon approach, and plastic and reconstructive surgeons offer all plastic surgical options including free flaps for full breast reconstruction following mastectomy which is the standard of care for a tertiary level breast service.