Radiotherapy for pancreatic cancer

Radiotherapy is the use of ionising radiation (high energy X-rays) to destroy cancer cells. The aim is to target and destroy as many of the cancer cells as possible by directing high energy waves (radiation) at the cancer site. This can be performed from outside the body (external radiotherapy) by directing a beam of radiation at the site, or from inside by drinking a radioactive liquid or placing a radioactive implant close to the tumour. Radiotherapy used in pancreatic cancer is external.

Like chemotherapy, there can be side effects because the radiotherapy can damage the surrounding normal healthy tissues. It may be given:

• Following surgery as adjuvant therapy to help reduce the chance of the cancer recurring

• For locally advanced disease

• To help relieve symptoms such as pain

• Before surgery as part of neoadjuvant therapy

Adjuvant therapy

Radiotherapy may be given together with chemotherapy following surgery; however there is little evidence to support this. The UK trial ESPAC-1 showed that there was no benefit from the addition of chemoradiotherapy after surgery whereas there was benefit seen with adjuvant chemotherapy.

Chemoradiotherapy is used more widely pre- and post- operatively in the US and some parts of Europe, although there is little evidence to support this approach.

Locally advanced disease

If the cancer cannot be removed surgically because it is too close to important blood vessels, but there are no signs that it has spread to other parts of the body, radiotherapy may be considered. It is very unlikely to cure the cancer, but it can help to control it and may even shrink it or slow its growth.

Less commonly the treatment may involve a combination of chemotherapy and radiation treatment (chemoradiotherapy). Very rarely following chemotherapy or chemo-radiation the tumour may shrink so that surgery becomes possible.

Relief of symptoms

Because radiotherapy has the potential to shrink tumours, it can be used to help relieve symptoms such as pain. Large tumours can cause pain because they are pressing into other organs or structures such as the bowels or spine. Thus shrinking the cancer will relieve this.

Neoadjuvant therapy

This is still considered experimental and as such would only be offered as part of a clinical trial - click here to find out more about clinical trials.

What happens during radiotherapy treatment?

Radiotherapy is given in small daily treatments called fractions, given Monday to Friday. You cannot see or feel radiation therapy. It is carefully planned, usually with the help of a CT scan to accurately define the area that needs to be treated, and likewise avoid normal tissue organs away from the tumour. It is usual to require approximately 4-6 weeks or 20-30 fractions of treatment.

You will feel some tiredness during radiotherapy though this is not usually as severe as with chemotherapy. Other side affects include nausea, abdominal discomfort and cramping and diarrhoea.

Because of careful radiotherapy planning the risk to surrounding organs such as the liver, kidneys and bowel is kept to a very low level. You will be reviewed regularly throughout your treatment.

There are long term risks from the radiotherapy in particular to the small bowel where we absorb our food. The risk is related to the amount of radiotherapy given. You should discuss with your oncologist the potential advantages and disadvantages of treatment.

If you are also to receive chemotherapy this is given as per usual with radiotherapy. It is now recommended that you start for some weeks with chemotherapy alone prior to receiving both treatments together.

A patient generally waits about 6 - 8 weeks before having a follow-up magnetic resonance image or computed tomography scan, to measure the tumour's response to treatment. The wait is necessary to allow possible internal swelling to subside.

Novel forms of radiotherapy

There are various novel forms of radiotherapy now available that are used to treat other types of cancer (such as small brain tumours and arterial aneurysms) but it is too early to say whether they are of benefit in pancreatic cancer.

These include treatments known as IMRT (intensity modulated radiotherapy), SBRT (stereotactic body radiotherapy) and cyberknife (a misnomer as it isn't a knife at all or a form of surgery just intense beams of radiation).

Some of these have been used in trials but no major trials for advanced cancer comparing cyberknife with other types of treatment including other methods of giving radiotherapy have been performed. Thus it is not known what impact they have on survival or quality of life compared to other treatments, and also importantly what the difference in side-effects is.

Due to the proximity of so many other organs care has to be taken to try to treat just the tumour itself and not damage other parts of the body or digestive system.

A recent trial of stereotactic body radiotherapy/cyberknife with chemotherapy for locally advanced (as opposed to metastatic cancer ie it hasn't spread to other parts of the body) pancreatic cancer showed similar survival rates to conventional chemoradiotherapy (locally advanced pancreatic cancer has median survival of around 9-12 months with treatment by chemotherapy or chemoradiotherapy) but a significant rate of duodenal ulcer development.

Further information

See the trials page for information on use of radiotherapy in trials in the UK and the National Cancer Institute trials database (select pancreatic cancer) for trials in the USA.