Breast Cancer Surgery, Axilla and When Radiotherapy Follows

Breast cancer surgery aims at locoregional control: clearing the cancer from the breast and from the axilla, the armpit lymph nodes to which it spreads first. The breast is treated by breast-conserving surgery or mastectomy, and the axilla by sentinel lymph node biopsy or axillary dissection. Radiotherapy follows almost every breast-conserving operation, but follows mastectomy only for a large tumour, positive nodes, or close or involved margins.

Dr. Jalaj Baxi, Director Surgical Oncology, Fortis Hospital, Noida, India, set out these decisions for doctors who refer patients rather than operate on them. This article follows his sequence: the choice for the breast, the choice for the axilla, and the radiotherapy that completes local treatment. How the patient reaches surgery, through triple assessment and staging, is covered in the guide to breast cancer diagnosis and management for general practitioners.

Breast-conserving surgery vs mastectomy

For the breast, there are two options: conserve it or remove it. Breast-conserving surgery takes two main forms:

• Lumpectomy: removal of the tumour with a margin of normal tissue around it.
• Quadrantectomy: removal of the quadrant of the breast that contains the tumour.

Mastectomy removes the whole breast, and in the standard operation the axillary lymph nodes are removed along with it. When breast-conserving surgery is chosen, the axilla is treated as a separate step.

When breast conservation is not possible

Dr. Baxi named two absolute contraindications to breast-conserving surgery:

1. Widespread disease in the breast. Cancer spread through the breast cannot be removed by a local excision.
2. Persistently positive margins after surgical attempts. If repeated excision still leaves cancer at the edge of the specimen, conservation has failed.

The main relative contraindication is a large tumour, or more precisely the ratio of tumour size to breast size. The purpose of conservation is a cosmetically acceptable breast. In Dr. Baxi's words, there is no point in conserving the breast if more than half of it has to be removed. He showed the result of poor patient selection: a conserved breast with a very poor cosmetic result, in a patient who was not suitable for conservation. Conservation succeeds only when the patient is selected for it.

Types of mastectomy

When the breast cannot be conserved, mastectomy follows. Dr. Baxi listed five types:

• Total (simple) mastectomy: removal of the whole breast.
• Modified radical mastectomy: removal of the whole breast together with the axillary lymph nodes, preserving the chest wall muscles. Dr. Baxi named it as the mastectomy offered when the breast cannot be conserved.
• Radical mastectomy: the older operation that also removes the pectoral muscles, now rarely performed.
• Skin-sparing mastectomy: removal of the breast tissue while preserving most of the skin envelope, usually to allow reconstruction.
• Robotic mastectomy: a newer approach, performed through small incisions with robotic assistance.

Indications for mastectomy

Whatever contraindicates breast conservation becomes an indication for mastectomy. The other indication is the patient's own choice. Dr. Baxi observed that most of his Indian patients prefer to have the breast removed and are not interested in conservation, so patient preference is a genuine indication in his practice rather than a formality. Treatment costs for both operations are listed on the breast cancer surgery cost page.

Risk-reducing mastectomy for BRCA carriers

Asked in the Live Discussion from this masterclass about prophylactic mastectomy in early breast cancer, Dr. Baxi limited it to patients with a genetically determined risk: those who test positive for a BRCA1 or BRCA2 mutation. In his practice, BRCA testing is done when there is a family history of breast cancer. Current guidelines also recommend testing for some patients without a family history, for example those diagnosed at a young age or with triple-negative disease.

Why the axilla is treated

Patients often ask why the axilla is operated on when the cancer is in the breast. Dr. Baxi's answer is anatomical: the axilla is the first station to which breast cancer spreads. Clearing the axilla controls disease there, and examining the removed nodes tells the team whether the patient is node positive or node negative. That result determines further treatment, which is why axillary surgery is as much about prognosis as about control.

The three levels of axillary lymph nodes

Axillary nodes are described in three levels relative to the pectoralis minor muscle:

An axillary lymph node dissection removes the nodes at these levels. It is effective, but it carries its own complications, the main ones being lymphoedema (chronic swelling of the arm), shoulder stiffness and numbness along the inner arm.

Sentinel lymph node biopsy: how it works

Sentinel lymph node biopsy (SLNB) is the newer concept. Instead of removing the whole axilla, the surgeon removes only the sentinel nodes: the first nodes that drain the tumour. If they are free of cancer, the rest of the axilla is very unlikely to be involved.

Dr. Baxi described the technique:

1. A radioisotope, or isosulfan blue dye, is injected around the tumour or into the subareolar area beneath the nipple. Most lymphatic drainage from the breast runs towards the axilla.
2. The tracer travels to the first draining lymph node and is taken up there.
3. The surgeon identifies the node by its blue colour, and a radioisotope detector confirms its activity.
4. Only that node is removed and sent for biopsy, to show whether disease is present.

Indocyanine green (ICG), a fluorescent dye, is a newer tracer option for the same purpose.

Sentinel node biopsy vs axillary dissection

The point of the technique, Dr. Baxi said, is that axillary dissection can be avoided in patients with early breast cancer and limited sentinel node involvement. This removes the complications of a full dissection with no adverse effect on outcome.

The last row matters for referral. Sentinel node biopsy needs a radioisotope or dye and a trained team, and it is not done everywhere. Where it is unavailable, axillary dissection remains the standard. A separate masterclass covers axillary management in breast cancer and the LYMPHA technique.

Radiotherapy after breast cancer surgery

Most patients with breast cancer need adjuvant radiotherapy, meaning radiotherapy after surgery. Dr. Baxi set out the indications by operation.

After breast-conserving surgery

Almost all patients whose breast is conserved need post-operative radiotherapy; omission is an option only for selected older women with small, node-negative, hormone receptor positive cancers who take endocrine therapy. Most patients also receive a boost dose to the lumpectomy area, an extra dose of radiation to the site from which the tumour was removed, particularly younger women and those with higher-grade tumours.

After mastectomy

Radiotherapy after mastectomy is given only in three situations:

1. The tumour is large.
2. The nodes are positive.
3. The margins are close.

Every patient with a positive margin after resection receives post-operative radiotherapy.

To the axilla

Dr. Baxi listed four indications for radiotherapy to the axilla:

• Node-positive disease with extensive extracapsular extension, where cancer has broken through the capsule of the lymph node.
• A positive sentinel node where no axillary dissection has been done.
• An axillary dissection that was not adequate.
• A high-risk patient in whom dissection has not been done.

Treatment costs for adjuvant radiation are on the radiotherapy cost page.

Surgery or radiotherapy in advanced breast cancer

In locally advanced breast cancer, surgery does not come first. Chemotherapy is given first, and surgery follows once the tumour has shrunk. Asked how surgery compares with radiotherapy for local control in advanced disease, Dr. Baxi was clear that radiotherapy is given only when surgery is not possible. If the patient responds to chemotherapy and surgery becomes feasible, the patient should have surgery. Radiotherapy comes in when the patient refuses surgery or surgery cannot be done. He did not consider radiotherapy an equivalent substitute for surgery in advanced cancer, although radiotherapy after surgery remains standard for locally advanced disease. The chemotherapy that precedes surgery, and the options when the disease is metastatic, are covered in breast cancer chemotherapy and metastatic disease options.