An insight into Radiotherapy - Radiotherapy and its physics (8/15)

Uploaded by OUlearn on 07.07.2008

One in three people will develop cancer
so most of us won't have to face it ourselves
but it will probably affect one of our family.
And having said that,
probably about one in four people will die from cancer.
So these days, with the ageing population,
it is more likely that as we don't die from other things
we may develop a form of cancer.
There are various screening programmes that are active in the UK
and about to become active looking at picking up cancers earlier.
So many of our treatments, in fact,
are not just looking at treating cancers when they're quite late
in a palliative, non-curative way,
but treating them earlier in a curative way.
My name is Andrew Doggart.
I'm a radiotherapy physicist here at the Berkshire Cancer Centre.
Radiotherapy may be defined as the management of malignant disease
by the use of ionising radiation.
In this tutorial you're going to see how different members of the team
including oncologists, physicists and radiographers
work together so that a patient may be treated using radiotherapy
in a safe and effective manner.
So that's vision so that controls all of the planning.
You've already seen clinical oncologist Paul Rogers.
Here is Jill Wyatt, one of the therapy radiographers.
She plans treatment and treats cancer patients using high-energy x-rays.
If you have problems with the machine,
you probably want to get into control group 8.
Paul Whittard is head of the radiotherapy physics section
which provides the physics and technical support
to the radiotherapy service.
This has been used for many, many years.
Kim Hare is the mould room technician
responsible for making the equipment necessary for immobilising patients
during radiotherapy treatment.
You can hear more from these members of staff
by clicking the link buttons.
Now let's go back to Paul Rogers for more background information
on cancer treatment.
When someone comes with a diagnosis of cancer,
the first thing to do is to stage the cancer
to find out how best to treat it.
By stage I mean to find out
whether the cancer is confined to one particular spot
of whether it has spread in the different ways that it can do.
Cancer can spread in one of two ways.
Either via the lymphatics to various lymph nodes
usually adjacent to the primary tumour,
or via the blood when the cancer may have metastasised
to other parts of the body: the lung, the liver, the bones or the brain.
And these days we perform, generally speaking,
a CT scan to assess that.
Maybe a bone scan as well.
Once one has ascertained whether the cancer is confined,
then you know how best to treat the cancer.
There are three different modalities for treating cancer.
One is surgery, one is chemotherapy and the other is radiotherapy.
Surgery and radiotherapy are the two local measures.
They treat just where you're cutting or shining the x-rays.
And those have the best chance of cure of cancers.
Chemotherapy is a systemic treatment that goes round the whole body
and therefore can either treat things once they have spread
or help to prevent things from coming back elsewhere.
So chemotherapy is generally not a curative thing up front,
although it is for some tumours,
and therefore the first and best treatment is usually surgery.
Radiotherapy is the second best option as a general rule
for curing cancers.
Having said that, there are some cancers
where one would want to use radiotherapy
in preference of surgery.
For example, if someone has a tumour of the larynx, the voice box,
to remove one's voice box has a big impact on life obviously
and communicating with the world.
Therefore if one can treat that with radiotherapy and preserve the organ,
preserve the voice box, clearly that's preferable.
And in early laryngeal cancer, the cure rates from radiotherapy are 95%
so they're very, very good, as good as surgery.
And other areas that are, if you like, equally effective as surgery
and therefore beneficial and organ sparing
would be prostate cancer, bladder cancer,
to name some of the pelvic tumours,
and there's also a role in breast cancer
where you can remove perhaps a smaller amount of breast tissue.
Gone are the days now where we have to remove the whole breast
with a small breast cancer.
You can remove the lump and then give some postoperative radiotherapy
to the breast to help prevent a recurrence in the breast.
So the two do go together as well.
Sometimes it is quite clear what treatment to advise patients to have.
For example, one would advise radiotherapy to the voice box
if one had an early laryngeal cancer.
However, when you have a prostate cancer, for example,
which is one of the tumours I particularly treat,
the patients do have a choice.
And sometimes it's very hard
for them to know the right treatment option for them.
Some patients will know that if they've got a cancer
they will want it out of their body
and they will not be happy until it's gone.
And those patients will generally choose surgery.
For others the idea of having major surgery
and being off work for six weeks
might be too much or too intrusive,
particularly if it's a very, very early prostate cancer
that was found almost by chance and is causing them no symptoms.
And for them the idea of radiotherapy
in one of the different forms of radiotherapy that we can give
is a far more preferable option.
So they don't have to take time off work or interrupt their lifestyles.