The main options are either breast-conserving surgery with radiation therapy or a mastectomy (surgery to remove the whole breast).

Often surgery for breast cancer is followed by a combination of chemotherapy, radiation therapy, hormone therapy or targeted therapy, depending on the features of the cancer. The treatment that is given after you have surgery is called adjuvant therapy, and it reduces the risk of the cancer coming back.

Chemotherapy or targeted therapy given before surgery is neoadjuvant therapy. Usually suggested for HER2+, triple negative and inflammatory breast cancers, it is also sometimes advised for hormone positive cancer.

Often treated with chemotherapy before surgery to shrink the cancer. If the cancer is HER+, you’ll also usually have targeted therapy before surgery. It is common to be offered a mastectomy.

If the chemotherapy has shrunk the cancer, you may be offered breast-conserving surgery instead. Surgery is usually followed by radiation therapy, hormone therapy and/or targeted therapy, depending on the cancer type.

When only part of the breast is removed, it is called breast-conserving surgery, lumpectomy or wide local excision.

The surgeon removes the tumour and some of the healthy tissue around it, so that you can keep as much of your breast as possible. The operation will leave a scar, and may change the size and shape of the breast and the position of the nipple.

A pathologist looks at the tissue to check for an area of healthy cells around the cancer – known as a clear margin. The pathologist will also give information about:

• the size and grade of the cancer
• whether there are cancer cells near the edge (margin) of the removed breast tissue
• whether the cells are hormone receptor positive and/or HER2+ or triple negative, unless this has already been reported on the core biopsy results
• whether the cancer has spread to any lymph nodes.

The pathology report will guide your doctors on what other treatment may be best for you. If there are cancer cells found close to the edge of the removed tissue (called an involved or positive margin), there is a higher risk of the cancer returning. You may need to have further surgery for more tissue to be removed (called a re-excision or wider excision), and a mastectomy may be suggested.

After breast-conserving surgery, you’ll usually have radiation therapy to destroy any remaining cancer cells in the breast or armpit.

Surgery to remove the whole breast is called a mastectomy or single mastectomy. It may be recommended if: 

• you have the BRCA1 or BRCA2 gene mutation
• there is cancer in more than one area of the breast
• the cancer is large compared to the size of the breast
• you have had radiation therapy to the same breast before and so cannot have it again
• it’s difficult to get a clear margin around the tumour
• you have inflammatory breast cancer
• cancer has come back or you have a new cancer in the same breast.

The nipple is usually removed in a mastectomy. In some cases, the surgeon may perform a skin-sparing or nipple-sparing mastectomy. This means that more of the normal skin – with or without the nipple – is kept.

If you have decided to have a reconstruction, and can have a skin-sparing or nipple-sparing mastectomy, the reconstruction is usually done at the same time.

If you don't have a reconstruction, you have the option of wearing a soft breast form with a specially designed bra while your surgical wound heals. Breast Cancer Network Australia provides a free bra and temporary soft form. To order a kit, speak to your breast care nurse.

After the wound has healed and the area is comfortable, you can then be fitted for a permanent breast prosthesis.

Removal of both breasts is called a double or bilateral mastectomy. If you need a mastectomy because of cancer in one breast, you may think it’s safer to have the other breast removed as well.

For most people, the risk of getting cancer in the other breast is low. If you have the BRCA1 or BRCA2 gene mutation, this does increase the risk of developing another breast cancer, so your surgeon may recommend a double mastectomy to remove both breasts.

Whether to have a double mastectomy is a complex decision and it’s best to talk with your treatment team about the risks and benefits.

Breast reconstruction is surgery to make a new breast shape, which is also called a breast mound. The surgery may be done using a silicone implant, using tissue from another part of your body, or a combination of the two.

It may be possible to have a breast reconstruction at the same time as a mastectomy (immediate reconstruction). You may prefer to wait for several months or years before having a reconstruction (delayed reconstruction). If you’re not having an immediate reconstruction but might consider it in the future, discuss this with your surgeon before surgery, as it will help them to plan the mastectomy.

Sometimes you may have to travel to a different hospital to have a reconstruction. Some people decide not to have a reconstruction and prefer to go flat, while others choose to wear a breast prosthesis.

The axillary lymph nodes, which are in and around the armpit, are where cancer cells from the breast usually spread to first. Removing some or all of these lymph nodes helps your doctor to check for any cancer spread.

The operation to remove lymph nodes is called axillary surgery. It is usually done during breast surgery but may be done in a separate operation. There are two main types of axillary surgery:

• Sentinel lymph node biopsy (SLNB) – when breast cancer spreads outside the breast, it first goes to particular lymph nodes in the armpit or near the breastbone called the sentinel nodes. A SLNB finds and removes them so they can be tested for cancer cells. If there are no cancer cells in the sentinel nodes, the rest of the lymph nodes are left in place. If there is more than a small amount of disease in the sentinel nodes, you may have axillary lymph node dissection or radiation therapy.
• Axillary lymph node dissection (ALND) – if cancer is found in the lymph nodes, then most or all of the axillary lymph nodes (usually 10–25) will be removed to reduce the risk of the cancer coming back in the armpit. The results also guide what other treatment your doctor recommends.

Side effects include arm or shoulder stiffness, weakness, reduced movement and pain; numbness in the arm, shoulder, armpit and parts of the chest; seroma (fluid collecting near the surgical scar); lymphoedema; and cording.

Side effects are usually worse after axillary lymph node dissection because more lymph nodes are removed.

Your treatment team may refer to trastuzumab by a brand name, such as Herzuma, Kanjinti or Ogivri. It works by attaching itself to HER2+ breast cancer cells, destroying the cells or reducing their ability to divide and grow. Trastuzumab also encourages the body’s own immune cells to help find and destroy the cancer cells.

Trastuzumab is used in combination with chemotherapy. It has been shown to increase the effect of chemotherapy drugs on early breast cancer. Most people have trastuzumab via a drip into a vein (infusion), but some people have it as an injection under the skin.

The first infusion (called the loading dose) takes about 90 minutes. The following infusions take 30–60 minutes each. You will usually have a dose every three weeks, for up to 12 months. The first four doses are given while you are having chemotherapy treatment.

Although side effects from trastuzumab itself are uncommon, they can include headache, fever and diarrhoea, and sometimes, how the heart works. Side effects are usually caused by the chemotherapy, which means that once chemotherapy finishes and you are continuing with trastuzumab only, most side effects ease.

There are a number of new drugs for people who have inherited a BRCA mutation, or whose cancer has developed BRCA mutations. These are called PARP inhibitors. Ask your doctor whether these drugs may be appropriate for you.