Radiotherapy for rectal cancer

• A quick guide to what's on this page
• Why and when you have radiotherapy
• External radiotherapy before surgery
• Internal radiotherapy before surgery
• Radiotherapy after surgery
• Planning treatment
• Having treatment
• More information about radiotherapy

Radiotherapy uses high energy rays to kill cancer cells. It is not often used to treat cancer in the large bowel (colon cancer). But it is often used to treat cancer that started in the back passage (rectum). Usually, you have this treatment at the same time as fluorouracil chemotherapy. The chemotherapy makes the cancer cells more sensitive to radiation.

To try to cure rectal cancer, you may have radiotherapy

• Before surgery (preoperative radiotherapy)
• After surgery (postoperative radiotherapy)

Another page in this section tells you about radiotherapy to treat the symptoms of bowel cancer.

Doctors use radiotherapy before surgery to

• Lower the risk of the cancer coming back (recurrence) after your operation
• Shrink tumours and make them easier to remove completely

If your tumour can be operated on you are likely to have a short course of 5 radiotherapy treatments in the week before surgery. This will kill many of the cancer cells. And it makes it less likely that any cancer cells will spread at the time of your surgery. You may have fluorouracil chemotherapy at the same time as the radiotherapy. Chemotherapy and radiotherapy given together are called chemoradiation.

If you have a large tumour you may need a longer course of treatment before surgery. The treatment may last up to 5 weeks. You may have fluorouracil chemotherapy at the same time. You usually have surgery a few weeks after this sort of radiotherapy, to allow the tumour to shrink.

A newer treatment for rectal cancer is high dose internal radiotherapy before surgery. This is called brachytherapy. You normally have a sedative before this procedure to help you relax. A tube containing radioactive material is gently pushed through your anus into your rectum, and positioned close to the tumour. It is left in place for a while. The aim is to shrink the tumour so that it is easier to completely remove it surgery. You have surgery a few weeks later.

Results from studies seem to show that people who have internal radiotherapy are less likely to need a colostomy than people who have external radiotherapy. But it is not clear whether they will live any longer. The National Institute for Health and Clinical Excellence (NICE) issued guidance in December 2006 stating that the procedure is safe and effective enough to be used for rectal cancer. But we need further research to see how well it works. Everyone who has this treatment must be closely followed up. Possible side effects of the procedure include making a hole in the rectum or bladder, tightening (stenosis) of the back passage, or a hole (fistula) developing between the rectum and the bladder, or vagina.

If you haven't had radiotherapy before your operation, your surgeon and cancer specialist may want you to have some external radiotherapy afterwards if

• Your cancer was difficult to remove
• Your surgeon thinks some cancer cells may be left behind
• Your cancer had grown through the bowel wall or spread to nearby lymph nodes

Radiotherapy after surgery is called adjuvant radiotherapy. You usually have this type of radiotherapy treatment over 4 to 5 weeks. You have treatment from Monday to Friday, so you have 20 to 25 treatments (fractions) in total. Giving the treatment in small fractions reduces the side effects to healthy tissues. You may have chemotherapy with radiotherapy. This is called chemoradiation.

Radiotherapy treatment is carefully planned. On your first visit, you lie under a large machine called a simulator. The simulator takes X-rays. The doctor uses it to work out where to give the treatment to

• Kill the most cancer cells
• Miss as much healthy body tissue as possible

For external radiotherapy, marks are made on your skin during the planning session. The radiographer uses these skin marks to line up the radiotherapy machine every day when you have your treatment. Don't worry if they wear off a bit. Your radiographer can draw them again. You will also have a few pinprick tattoos made during planning to make sure that the radiotherapy machines are positioned as accurately as possible.

You have radiotherapy in the hospital radiotherapy department.

Internal radiotherapy (brachytherapy) usually just takes one or two sessions.

For external radiotherapy, you are usually treated once a day from Monday to Friday, with a rest over the weekend. The treatment before surgery for rectal cancer lasts from 1 to 5 weeks, depending on the size and type of your cancer and the hospital treating you.

If you are having radiotherapy after surgery, the course of treatment may be up to 6 or 7 weeks long.

The actual treatment only takes a few minutes. The radiographer positions you on the couch and makes sure you are comfortable. You will be left alone while you have your treatment, but the radiographers can hear you through an intercom. You can talk to them or ask them questions.

Radiotherapy doesn't hurt. You won't be able to feel it, but you need to lie very still for the few minutes that you have your treatment.

Radiotherapy doesn't make you radioactive. It is perfectly safe to be with other people, including children, throughout your course of treatment.

To find out more about radiotherapy, look in the main radiotherapy section in CancerHelp UK. It tells you about

• What radiotherapy involves
• How your treatment is planned
• Possible side effects

There are books and booklets about radiotherapy, some of which are free. Look in the treatment reading list for details.

There is also information about the latest research into radiotherapy for rectal cancer in this section of CancerHelp UK.