Breast cancer surgery

The two main operations

Breast conservation (also called a wide local excision or lumpectomy) removes the cancer together with a rim of normal tissue around it, keeping the rest of the breast. It is almost always followed by radiotherapy.

Mastectomy removes all of the breast tissue. It is recommended when the cancer is large relative to the breast, when there is more than one cancer in separate areas, when radiotherapy is not suitable, or when a patient chooses it after understanding the alternatives.

Where both are appropriate, international evidence has consistently shown that breast conservation with radiotherapy and mastectomy give comparable long-term survival. The choice between them is therefore rarely a choice about survival.

How the decision is actually made

Patients often ask which operation is better. That is the wrong question, and the right one is more interesting: which operation is right for this cancer, in this breast, in this person’s life.

The factors that genuinely drive the decision are the size of the cancer relative to the size of the breast, whether the cancer is in one area or several, the biology of the tumour and how it is likely to behave, whether clear margins can realistically be achieved, whether radiotherapy is available and appropriate, genetic risk where relevant, and what the patient wants to live with afterwards.

That last factor is not a courtesy. Two people with clinically identical cancers can reasonably choose differently, and both can be right.

Lymph node surgery

Whether breast cancer has reached the lymph nodes under the arm affects both staging and treatment. Two approaches are used:

Sentinel lymph node biopsy identifies and removes the first few nodes the breast drains into. If those are clear, the remainder usually are too, and no further node surgery is needed. This spares most patients the side effects of a full clearance.

Axillary clearance removes a larger group of nodes, and is used when nodes are already known to be involved.

Surgery is one part of the treatment

Breast cancer is treated by a team, not by a surgeon alone. Chemotherapy, hormonal therapy, targeted therapy and radiotherapy each have a role depending on the stage and the biology of the individual cancer.

Treatment decisions are made in a multidisciplinary team meeting where the surgeon, medical oncologist, radiologist, pathologist and radiation oncologist review the case together. The surgeon is one voice in that room, not the only one.

Some patients have chemotherapy before surgery rather than after, to shrink a cancer and make a smaller operation possible. Whether that is appropriate is a decision for the team.

Margins, and why they matter

A margin is the rim of normal tissue removed around the cancer. Achieving a clear margin: no cancer cells at the cut edge, is one of the surgeon’s central responsibilities, because it directly affects the risk of the cancer returning in the same place.

If the pathology report shows the margin is not clear, further surgery may be recommended. This is not a complication or an error; it reflects that the true extent of a cancer is not always visible during the operation.