Side effects / complications

Breast cancer

Side effects and complications

Possible side effects from surgery include:


This is a collection of clear fluid which accumulates in the surgical cavity during healing. After mastectomy, fluid can build up between the skin flaps and the chest wall, causing a balloon-like swelling with obvious fluid movement. If it is large and uncomfortable your breast care nurse may aspirate (remove) the fluid using a simple syringe and needle. Occasionally you may need repeated aspirations before the seroma resolves or a small seroma drain may need to be placed to aid adherence of the skin flaps to the chest wall. Aspirations increase the risk of infection but a persistent, large seroma may result in a poorer cosmetic outcome if not dealt with. A small seroma may be left to resolve on its own. Seromas may also develop in the armpit after axillary surgery and can quickly become uncomfortable. They are treated in the same way as a breast seroma.


There is a small risk of post operative bleeding and haematoma formation after breast surgery, causing pain and significant bruising. A small haematoma can be left to resolve naturally but larger ones may need surgical evacuation. It's important to monitor the area for signs of infection.


Breast cancer surgery and removal of axillary lymph nodes increases the risk of lymphoedema, a chronic swelling of the affected arm. It may also develop in the breast, chest wall or back. A referral to a lymphoedema therapist at the first sign of any symptoms is crucial so that the condition can be managed without it progressing. Women who have had an axillary node dissection would benefit from an early discussion with a lymphoedema therapist to learn how to protect their arm and reduce the risk of developing lymphoedema in the future.

The risk of developing lymphoedema after sentinel node biopsy alone is low.

Read more about lymphoedema

Cording (axillary web syndrome)

Cording, also known as axillary web syndrome occurs in about 10% of patients after axillary surgery. A tight, uncomfortable cord-like structure can be felt (and sometimes seen) in the armpit and often extending down the arm. This restricts movement and requires referral to a lymphoedema therapist or physiotherapist. Treatment aims to release the tight tissue and restore a normal range of movement, and may involve stretching and flexibility exercises, massage, and appropriate pain relief. Some therapists now use low-level laser therapy to hasten recovery. Cording is not associated with lymphoedema and does not raise the risk of developing lymphoedema.

Restricted range of movement in shoulder

When recovering from breast cancer surgery, patients may have drains inserted into the axilla or chest wall and are advised not to raise their arms above 90 degrees until these are removed, to reduce the risk of bleeding and seroma formation. This sometimes results in restricted range of movement in the shoulder. You should be given a programme of arm exercises post-operatively and it's very important to follow this and see a physiotherapist if you are not making progress. The range of movement in your shoulder should ultimately return to pre-surgery range if mobilised properly.

Nerve pain or numbness

Following axillary node dissection you may have an area of numbness, particularly down the back of the arm and in the axilla (armpit). This may improve over time, although it may be permanent as some of the nerves which supply sensation to the skin are divided during surgery in order to remove the lymph nodes. It's important to protect the numb area from sunburn, sharp objects or anything that may cause injury.


All surgical procedures carry a risk of infection. It's important to report any changes such as redness, heat, swelling or increased pain in or around the surgical wound. Diabetes, obesity, older age and cigarette smoking are all associated with a higher rate of wound infection.

Tissue necrosis

If the blood supply to the skin and underlying tissues is compromised, oxygen supply to the cells is reduced. This can sometimes happen when mastectomy skin flaps are very thin. The lack of oxygen causes the tissue to die, forming a black, hard scab that might need to be removed to let the remaining tissue heal. Smokers are at an increased risk of tissue necrosis.

Fat necrosis can also occur in the breast following partial mastectomy. Fatty tissue that dies or has been damaged can form a firm lump or sometimes a cyst filled with an oily substance (oil cyst). These will often resolve over time without treatment.


Some degree of short-term pain is expected after any surgery but for most people this resolves within a few weeks. However, some people report persistent discomfort in the longer term in the breast, chest wall or arm following breast and axillary surgery. This can sometimes be due to nerve damage (neuropathic pain) and is often described as hot, burning, sharp or stabbing in nature. The exact cause of this syndrome is not well understood. Some cases are mild and can be managed with anti-inflammatories while others require comprehensive pain assessment and more extensive pain management.

Some women also report phantom nipple pain after mastectomy.

Weight imbalance after mastectomy

The removal of a breast (particularly if it is large) can cause a change in posture and resulting neck back or shoulder discomfort. Physiotherapy and a well fitted prosthesis will usually remedy this.

Cosmetic issues

In most cases, breast conservation surgery leaves a cosmetically acceptable breast but some women may notice that their breast is smaller and sits higher than the opposite side.Occasionally there may be a noticeable dent or distortion. A partial breast prosthesis is available to correct the appearance under clothing or in more severe cases, corrective breast reconstruction techniques may be an option.

Following mastectomy, many women become aware of an area at the end of the mastectomy scar, towards the back, which appears swollen. In most cases this is normal fat tissue which becomes more apparent after the breast tissue has been removed, however show your surgeon if this is concerning you.

If you are experiencing the above side effects, or any others, talk to your medical team or call 0800 BC NURSE.