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Radiotherapy
This article was revised by Wendy Green in 2001.
Wendy Green trained at Groote
Schuur Hospital, Cape Town, South Africa and has a National Diploma in
Therapy Radiography. More recently she has worked at the Royal Free
Hospital, Hampstead.
She has a specific interest
in smoothing the cancer patient’s pathway through diagnosis, treatment and
follow-up, particularly by providing understandable information to help
overcome anxiety.
Our thanks to Bethan Roberts, Radiotherapy Nurse Specialist, Churchill
Hospital Oxford, for her help with the second revision of this publication.
Why radiotherapy for lymphomas?
Radiation causes damage to lymphoma cells to a
greater degree than normal cells; this is the basis for the use of
radiotherapy - radiation treatment - to combat lymphoma. In addition, the
healthy tissue which is damaged by radiation is able to repair itself,
whereas the cancerous tissue does not have this ability.
Lymphoma cells are
particularly sensitive to radiation (more so than breast or lung cancer
cells, for example), and so the dose of radiation needed to eradicate the
diseased cells is comparatively low. Consequently, the toxic effects on the
normal cells that will be included in the treatment area are kept to a
minimum.
Radiotherapy is
targeted at the site of primary disease and any areas of known or suspected
spread. For Hodgkin lymphoma (formerly known as Hodgkin's disease) there are
common
sites of primary disease and likely routes of spread through certain lymph
node groups.
Non-Hodgkin lymphomas are less predictable in
that they arise in a wider variety of sites, and can occur wherever
lymphatic tissues exist, that is, anywhere in the body. They are, however,
no less sensitive to radiotherapy than the lymphoma cells in Hodgkin
lymphoma but the exact method of radiotherapy treatment will be more
variable.
Comparing
chemotherapy and radiotherapy
Radiotherapy is a
treatment which is delivered to precisely defined areas of the body, whereas
chemotherapy is a systemic treatment whereby drugs circulate throughout the
body.
Patients with
lymphomas often receive both radiotherapy and chemotherapy. Whereas
chemotherapy is normally given at certain intervals over many months,
radiotherapy is delivered daily over a few weeks. Most radiotherapy patients
are treated on an out-patient basis. Sometimes, a course of chemotherapy is
given first to shrink the tumour so that the area to be irradiated is
smaller.
What does
radiotherapy involve?
There are many myths
about radiotherapy; what it is, how it is given and what patients have to go
through during a course of treatment. Here are some facts.
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Not all hospitals
have a radiotherapy department. This is because the equipment used is
'high tech', expensive, and the staff are specialised. So, unless you live
in a major city, you might have to travel some distance or spend some time
on a ward during your course of treatment.
-
Radiotherapy is
essentially a very powerful, carefully focussed x-ray beam. This beam is
only 'on' for the very brief time that the area of the body is being
irradiated. When the beam is 'off' there is no radiation present in or
around the patient. The patient does not become radioactive.
-
Like an ordinary
x-ray, radiotherapy is painless and cannot be seen.
-
Claustrophobia
is seldom a problem as the treatment room is usually quite spacious and
the machine does not form a ring, or tube, around the patient.
-
When radiotherapy
was first used as a treatment for cancer, patients used to suffer severe
burns from the treatment. Nowadays, the machines and treatment techniques
have been greatly improved and refined to minimise this side-effect.
Although some patients still experience a sunburn reaction in the area of
skin being treated (the neck area is particularly prone to this), most
people complete their treatment course with only a mild 'pinking' of the
skin, and possibly some dryness and itchiness. This heals up in due course
after the treatment.
Once it has been
agreed that you are to have a course of radiotherapy, a series of events
will occur. During this time, you will be under the care of a radiation
oncologist or radiotherapist. This is the doctor who will decide on exactly
where to target the radiotherapy, and will keep a check on you as you
proceed through the course of treatment.
First visit to radiotherapy
Before commencing
radiotherapy, many investigations will have been undertaken to determine
which type of lymphoma you have and exactly where in the body it is located.
All this information is then used by the radiotherapy team so that your
treatment is tailored to your requirements.
On your first
appointment you are likely to visit a preparatory room, the Radiotherapy
simulator. This is not a treatment room, but here a number of important,
precise details of your treatment are decided. In this room therapy
radiographers will take several x-ray pictures by placing the machine
at different angles. Then measurements of your body and the machine settings
are taken, and marks are made on your skin that will be used for daily
reference on the treatment machine. Most of these marks will be made with
felt-tipped pens. However, for reference should you require further
treatment in the future, a few permanent marks have to be made. These are
usually two or three small dots of ink just under the surface of the skin.
When having
radiotherapy, the position in which you lie is very important to ensure
accurate treatment. It is also important to keep as still as possible,
allowing for breathing of course! You will be lying in an identical position
when you are subsequently treated in another room. Only the clothing in the
area to be treated will need to be removed.
If you are being
treated for disease in the head and neck area, it is likely that you will
also need to visit a mould room where 'shells' are made of clear, thin perspex. These shells help to keep the head still during treatment and will
fit like a mask. These are very important in ensuring the radiation is
targeted to precisely the right area. One advantage of a shell is that you
will not need to have marks drawn on your skin as all the reference marks
are transposed onto the shell.
Some people find
wearing a mask quite daunting, and this is understandable. It is important
to communicate your concerns to the staff as measures can be taken to make
it easier for you.
These shells or
'masks' are not meant to protect the head from radiation, but rather to help
direct the radiation beam to the right area. However, it is often necessary
to shield healthy tissue near the disease from the radiation. This is done
by placing blocks of lead, or some other high density alloy, in the path of
the radiation beam. A tray will be fixed to the head of the machine, and the
blocks of lead attached to this tray in carefully demarcated positions.
Planning
During this part of
the procedure, the patient does not actually have to be present. The work is
going on ‘behind the scenes’ using all the information obtained during your
visit to the simulator.
All the information
from the simulator and mould rooms will be collated and calculations
performed to determine exactly the radiation dose to be received by the body
and how much will be distributed to the diseased cells and to normal
structures. Normal tissues always receive some radiation and this is why
side-effects arise, but the amounts received are carefully checked to be
within acceptable limits. Often, very sophisticated computer software is
used to do these calculations.
In addition to the
Computerised Tomography (CT) scans performed to confirm diagnosis of
disease, a special CT scan may be taken on a simulator or CT scanner in the
radiotherapy department to help precisely calculate your treatment. In
total, it may take several visits to complete all of the simulation and
planning procedures.
Your treatment
Nowadays, most people
are treated with high energy x-rays electrically produced by a machine
called a linear accelerator. Just like x-rays used to visualise the inside
of the body, x-rays used for radiotherapy are totally invisible and painless
but of a much higher energy. Linear accelerators are excellent at delivering
radiation very accurately and quickly. They are operated by therapy
radiographers.
The machine is housed
in a special treatment room. Here you will lie on a narrow ‘table’ while the
machine is set up and aimed at the exact area of your body to be treated. To
do this, the room lights will be dimmed and you will probably notice a beam
of light coming from the head of the machine, as well as some red laser
beams coming from various points in the room. These are simply there to assist the team
to set you and the machine up in the correct position to ensure accuracy.
The length of time of
exposure to radiation will only be a few minutes duration in total. However,
it may take between ten to twenty minutes for the radiographers to achieve
the correct machine setting. Before switching the machine on, they will turn the lights
up and leave the room, but will be constantly monitoring you on closed
circuit television. Most rooms are equipped with cassette or CD players, and
you may find it helpful to take along some music you enjoy.
Courses of treatment
are normally given over several weeks with patients usually attending daily,
Monday to Friday. This can vary, however, and it should be stressed that
radiotherapy is tailor-made and that a patient scheduled to receive a
greater number of treatment days than someone else does not necessarily
have a more serious condition.
It is worth
remembering that radiotherapy machines are highly complex and require
constant maintenance. They are made to 'fail' if any parameters are even
marginally out of tolerance because accuracy of treatment is imperative. You
may well experience some delays and breakdowns during the course of
treatment as a result of this. You will probably find this less stressful if
you always make sure you take something to do, and if you keep your daily
activities flexible to accommodate any delays.
Effects of
radiotherapy
Any side-effects will
depend on several factors:
-
The area of the
body to be treated
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The dose of
radiation used and the time scale over which it is delivered
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The
effects of any previous or concurrent chemotherapy
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The general
condition of the patient.
It is not true that
radiotherapy always makes people feel sick or that they will suffer from
hair loss. For example, if someone has a lymphoma of the skin on their leg,
the radiation will not cause diarrhoea or vomiting or cause the hair on the
scalp to fall out. An important rule of thumb to keep in mind is that the
side effects of radiation are local to the
area being treated.
-
As mentioned
earlier, one of the most certain side-effects of radiotherapy is a skin
reaction, in the treatment area, which usually takes the form of mild
sunburn, often with associated dryness and itchiness.
-
In addition, bone
marrow producing areas might unavoidably be treated. This could lead to a
drop in the blood count i.e. the number of blood cells circulating in the
blood stream.
-
If the mouth and/or
oesophagus (passage from the mouth to the stomach) are in the treatment area this
could lead to discomfort when swallowing, a lack of saliva, and a temporary loss of appetite.
The thyroid gland's function may be impaired. If this is suspected,
investigations will be carried out after the course of treatment and a
form of hormone replacement therapy may be necessary.
-
Treatment to the
pelvic area may lead to an episode of diarrhoea. If this occurs, keep your
fluid intake up and an over-the-counter remedy may be taken. Be sure to
tell the treatment staff.
-
Treatment to the
abdomen may cause nausea and vomiting. This can often be avoided, or at
least minimised, by taking anti-sickness medication before treatment. This
should be prescribed by the radiotherapist.
-
It is also common
for people receiving radiotherapy to feel quite fatigued as the course
progresses. This is often worse if the patient has already had a course of
chemotherapy. It is thought that the reason for this tiredness is partly
due to the fact that many toxins are being released into the system as the
tumour cells die, and the body has to work hard to rid itself of them.
In general, side-effects of radiotherapy tend to become more evident towards the latter part
of treatment and will probably be at a peak just after the course has
finished. The effects will start to subside a few weeks later. Some patients
will experience very few side-effects at all. Effects of treatment are
carefully monitored during treatment, and advice and medication will be
available from the staff of the radiotherapy team. There are also various
precautions you, as the patient, can take to minimise side-effects (see
below).
It is common for most
patients with lymphoma to attend for radiotherapy as outpatients so that
they may continue to lead their lives as normally as possible. Modern
technology, specialist staff and large centres of excellence in radiotherapy
and oncology, along with information and available support, have helped to
provide some of the most sophisticated medicine and individualised
treatments available.
How to help
yourself when undergoing radiotherapy
You are likely to
receive written instructions from the treatment team about skin care and
other precautions you should take whilst on radiotherapy. Be sure to follow
these instructions carefully and to ask the team if there’s anything you are
not sure about.
Skin care
-
Only use the cream
given to you by the staff, and not any over-the-counter creams. Apply it
gently to the area treated and make sure there isn’t a layer of cream on
your skin when you have the treatment.
-
Be very gentle with
your skin in the treatment area; don't cause any friction to the area by
rubbing or scratching it.
-
Use a mild or baby
soap in the treatment area, and tepid water. Pat the area dry with a soft
towel, don’t rub.
-
Do not use perfume,
deodorant, strong soaps, powders or lotions on the skin of the
radiotherapy site during the weeks you are receiving treatment and until
any skin reaction has subsided.
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Do not attach any sticking plaster or micropore to the treatment area.
-
Wear loose clothing
and natural fibres (such as cotton) next to your skin to help minimise
skin irritation.
-
Only use an
electric shaver, if shaving is necessary in the treatment area.
-
Avoid exposing the
skin to extremes of temperatures such as ice packs or heat pads.
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Avoid exposing the
treated area to sunlight during and for sometime after treatment.
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Preferably keep the
treated area covered. After the treatment, if it is exposed to the sun,
always use a high factor sunscreen on the area. The Lymphoma Association
has a leaflet entitled 'Sun Safety' which is available by calling the
Helpline.
Further tips
Revised December 2003
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