Women who suffer painful swelling in an arm following breast cancer treatment should be encouraged to exercise, experts have said.

Lymphoedema is a long-term condition that causes swelling in the body’s tissue, leading to pain and loss of mobility. There is no cure.

Some women worry that exercise will make the problem worse but new guidance from the National Institute for Health and Care Excellence (Nice) says it could improve their quality of life.

Lymphoedema is caused by damage or disruption to the lymphatic system whose job it is to drain excess fluid from tissues.

In breast cancer, surgery is often necessary to remove lymph glands to prevent the disease from spreading, but this can damage the lymphatic system.

Radiotherapy, where controlled doses of high-energy radiation are used to destroy cancer cells, can also cause it, as can a blockage of cancer cells.

Every year in the UK, almost 10,000 people with breast cancer are thought to develop lymphoedema in their arm following treatment.

The new Nice guidance, which is subject to consultation, says doctors and nurses should discuss with patients how exercise may improve their quality of life.

They should also stress that the current evidence shows “exercise does not prevent, cause or worsen lymphoedema”.

According to the NHS website, other treatments people can try include massage and compression garments.

Mark Baker, director of the Nice centre for clinical practice, said: “Lymphoedema is a long-term condition which occurs when the body’s lymphatic system becomes damaged and is unable to drain fluid in the normal way.

“For breast cancer patients, lymphoedema may occur as a result of treatment – such as surgery or radiotherapy – or cancer cells blocking the lymph system. This results in swelling that is often painful and makes joints stiff and difficult to move.

“Some people may be cautious of taking up exercise as they may think it could make their lymphoedema worse or bring it about in the first place.

“Our proposed new recommendations should clear up any confusion relating to the role that exercise can play for people with or at risk of this condition.

“With no cure available for lymphoedema, it is important that we provide clarity on effective ways to manage and control it where there is evidence to do so.”

According to Cancer Research UK, one in five people who have been treated for breast cancer will go on to develop lymphoedema in their arm.

Sally Greenbrook, senior policy officer at Breakthrough Breast Cancer, said: “We know that many women struggle to manage their lymphoedema and that some worry that exercising can make the symptoms worse.

“We welcome the introduction of clear guidelines to help healthcare professionals encourage women with lymphoedema to exercise in a way that may help to reduce the pain it can cause, and in turn improve their overall quality of life.”

Mia Rosenblatt, head of policy and campaigns at Breast Cancer Campaign, said: “We know that exercise can benefit a range of conditions, including breast cancer, and contribute to a patient’s general health and wellbeing. We therefore welcome the recognition of this.

“However, while it is positive that Nice has started to implement the new process of rapidly reviewing different elements of its guidelines, we believe that this rapid review of the advanced breast cancer guideline should have also considered the evidence around the benefits of a biopsy of recurrent or metastatic breast cancer.

Jackie Harris, clinical nurse specialist at Breast Cancer Care, said: “Lymphoedema affects a significant number of people after breast cancer and swelling in the arm, hand, fingers, breast or chest can severely restrict movement and impact their lives.

“Lymphoedema can be controlled but will never go away and we know that regular exercise has many benefits for those living with or at risk of lymphoedema. Regular movement in everyday life or work can help keep joints supple and aids lymph drainage and extra exercises can also be useful if swelling restricts movement of the arm.

“It is important that Nice is highlighting this new evidence and we hope that the guidelines will help patients feel more confident about exercising after breast cancer.”