Radiotherapy to the Pelvis

Before you start your treatment, you must sign a consent form stating that you understand what the treatment involves, what the side effects are, and that you are willing to proceed. Radiotherapy must be ‘planned’ beforehand. This is also known as ‘measuring up’ and is important, as every person is different – we differ in shape and size, and (believe it or not) the position of our internal organs. This usually involves having a CT scan, sometimes with oral contrast or an injection of contrast. Your position on the treatment couch will be lined up using lasers, and the radiographers will be taking measurements. Small tattoos will also be placed to mark position.

All the clever stuff then goes on behind the scenes when you are back at home. Firstly the doctor decides what he wants to treat with radiation, and also identifies the critical areas to avoid – such as bladder, hips and small bowel - This is all marked on the scan. The physics department then do a lot of work to decide how best to treat the area the doctor has identified, and also how to best avoid the critical areas. This can take a long time and be very complicated, and discussions often have to take place with the doctor. The physics department will then decide how many beams of radiation to use, from which angles, and where to shield out critical areas. The doctor will examine the final radiation treatment plan, sign it off, and prescribe the dose and number of fractions of treatment.

The plan is then double and triple checked to make sure there are no mistakes, before the data is fed into the radiotherapy treatment machine (Linac) computer. There it stays until you have completed your treatment.

Radiotherapy treatment does not hurt. We direct beams of high energy x-rays into the cancer, taking great care to avoid normal tissues. Unfortunately normal tissues cannot be avoided completely, and this is why radiotherapy has some side effects. You will not feel anything during treatment. It is like having a scan. Treatment takes roughly 15 – 20 minutes, and most of this time involves the radiographers making sure you are in the right position so we are sure to treat the correct area each day. Radiotherapy is often given over several weeks in order to give normal tissues time to recover each day.

Aim of treatment

The benefit of having radiotherapy for rectal cancer is either to shrink the cancer to reduce symptoms (palliative radiotherapy) or attempting to cure the cancer (radical radiotherapy) which is done in conjunction with an operation, and often involves chemotherapy given at the same time. The aim of treatment may be different for each person and the doctor will discuss this with you. The doctor will also discuss with you any other treatment options and what might happen if you had no treatment.

Immediate side effects

Here are some of the more common side effects:

  • Tiredness following treatment. Extremely common. This can last for a number of weeks after treatment has ended. Make sure you take it easy and rest when you feel tired.
  • Skin in the treated area becomes a little pink or red, like sunburn. It may also feel dry or itchy. You may bathe or shower during treatment, but do not have the water too hot. Use mild baby soap, but try not to rub the treated area, particularly if it is red or itchy. It’s best to pat the area dry with a soft towel. Avoid perfumed talcum powder or lotion. If your skin is very sore, ask your doctor for advice. You will be given a moisturising cream to apply to the treated area and the situation will be constantly reviewed during your treatment. The skin around the anus can get especially sore and require pain killers.
  • Diarrhoea – can vary in intensity, but usually controllable using Imodium (loperamide) tablets. The chemotherapy can also cause diarrhoea.
  • Nausea – can occur when small bowel is irradiated, and is treated with standard anti sickness tablets. Chemotherapy given with the radiation can also sometimes cause nausea.
  • Pain opening bowels – This is because of ‘proctitis’ or inflammation of the back passage caused by the radiotherapy. This side effect is greatly reduced if you have a colostomy (stoma bag). It is treated using pain killing tablets and ointment.
  • Hair loss can occur within the radiation field after 2 – 3 weeks and is usually temporary.
  • Bleeding from the back passage. This can often occur in small amounts and is usually nothing to worry about. If the bleeding is happening every day, or there are large amounts of blood being lost then you must tell the doctor immediately, as urgent treatment may be required.
  • Passing water more frequently, or pain passing water. This is fairly common, and is due to irritation of the bladder caused by the radiation. It feels a bit like having cystitis. Drink plenty of water to keep the urine dilute, cranberry juice can help reduce the symptoms. You will be asked to give a sample of urine just to make sure you haven’t developed a urine infection.

 

Possible late side effects of treatment

  • Irritable bowel. This is very common following pelvic radiotherapy, and certain foods with high fibre content, or spicy foods, can set it off.
  • Impotence in men. This can occur as a direct result of surgery, but in patients having radiotherapy the risk is higher. It often develops months later, and may improve over time.
  • Stricture (narrowing) of the bowel can be caused by scar tissue and may necessitate a operation to dilate or remove the bit of bowel affected. Thankfully this is extremely unusual.
  • Radiation can also cause cancer as well as treat it. This is rare and unusual and often takes 20 years, and your doctor will carry out the treatment because its benefits greatly outweigh any risks.

 

During treatment

A doctor will see you in the radiotherapy department or clinic during treatment. This will be an opportunity to discuss any problems.