Breast Cancer Surgery

The first objective of breast cancer surgery is to provide adequate excision, or removal, of the tumour in order to reduce the chance of the tumour coming back in the breast (local recurrence) at a later date. Following removal of the tumour that has arisen in the breast (primary tumour) accurate measurement of the tumour size and the tumour grade will contribute to the second objective which is to allow accurate staging of the tumour. This in turn helps to plan the next stage of treatment following surgery which is called adjuvant (or additional) therapy.

Following a diagnosis of breast cancer the majority of patients will have surgery as their initial treatment. There are two main reasons for operating on breast cancer:

1. To provide an excellent local treatment for the disease
2. To accurately stage the disease to determine what treatments to use following surgery.

Most patients will require surgery to the breast and axilla (underarm area).
The type of breast surgery will depend on the size and position of the lump as well as the size of the breast. Patients with smaller lumps and/or larger breasts are usually suitable for a wide local excision sometimes called breast conserving surgery or lumpectomy. Patients with larger lumps and/or smaller breasts will usually benefit from mastectomy which can be performed at the same time as immediate breast reconstruction.
The majority of patients will undergo wide local excision of the primary tumour but if patients are recommended to have a mastectomy then it can be combined with breast reconstruction and this can be carried out either at the time of the mastectomy or as a delayed procedure at a later date. Previous research studies have shown that the extent of the surgery does not influence the survival from the breast cancer i.e. having more extensive surgery (mastectomy) does not mean a better survival rate when compared with wide local excision.
In determining the most appropriate form of surgery a breast surgeon will take into account the size of the tumour and whether it occurs in one of more sites in the breast, the position of the tumour (central or peripheral) and the size of the breast.
All breast cancer surgery also involves surgery to the lymph nodes under the arm as it is extremely important to know if tumour cells have spread to this area or not. The majority of patients will be suitable for sentinel node biopsy, a relatively new technique that involves identification and removal of the first group of nodes under the arm. If tumour cells have spread to the lymph nodes then the optimal treatment requires removal of the majority of lymph nodes, an operation called axillary clearance.


Some form of surgery to the axilla (underarm) will always be required following a diagnosis of invasive breast cancer. The axillary lymph nodes that are present under the arm drain much of the lymphatic fluid from the breast and the arm via a network of lymphatic channels. It is through these lymphatic channels that tumour cells can spread from the primary tumour to the lymph nodes under the arm. At present this tumour spread or metastasis will occur in approximately 40% of patients with a diagnosis of invasive breast cancer. In addition assessment of the lymph nodes to find out whether they have tumour spread or not also forms an important part of the staging of the tumour and also helps plan adjuvant therapy.


There are two reasons for performing axillary (underarm) lymph node surgery:

The first aim of axillary surgery is to provide an accurate assessment of whether tumour cells have spread from the primary tumour to the axillary lymph nodes. This can be performed either by sentinel node biopsy or axillary clearance itself. The assessment of whether the lymph nodes are negative or positive for tumour cells is the single most important factor in determining prognosis and planning additional (adjuvant) therapy following the surgery.

The second aim of axillary (underarm) surgery is to provide effective local treatment in those patients where tumour cells have spread, or metastasised, to these lymph nodes.

This would usually take the form of an axillary node clearance where the majority of lymph nodes are removed. Tumour spread to the lymph nodes is usually detected following sentinel node biopsy.  It may also be detected prior to surgery by ultrasound-guided needle biopsy of axillary lymph nodes that are suspicious on ultrasound scanning.  This allows these patients to proceed straight to axillary clearance, thus avoiding two axillary operations.

Approximately 40% of all patients with breast cancer have tumour spread to the axillary lymph nodes.  The majority of these patients will require an axillary clearance.