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There are different ways of treating tumours with radiotherapy.
The standard way really in the UK, Europe and the USA
involves what we call a two-gray fraction,
a two unit treatment of radiotherapy per day
for curative, radical courses over six, perhaps seven week period of time.
For palliative treatments when we're not looking at curing cancer,
but we're looking at controlling symptoms,
we treat either in a single treatment which is usually a much bigger dose,
maybe an eight-gray, an eight unit treatment,
or possibly a ten-gray treatment,
or even a five fraction treatment over a week,
when one wants to give a bit more of a dose.
But even then, when we're looking at radical treatments now,
there are different treatment regimens.
The standard being the six week course,
but there are what we call hypo-fractionated treatment regimes,
where we're giving fewer fractions, fewer treatments per day,
to achieve the same overall effect.
And when one shortens the number of fractions that you give,
you have to give slightly bigger fractions per day.
So, for example, with prostate cancer,
we might treat with 70 to 74 gray over seven, seven and a half weeks,
with some hormone therapy,
or, 55 gray in 20 fractions over a four week course,
not including the weekends.
How do we decide?
There are a number of ways.
As I said , the standard is usually the two-gray long course,
but, if a patient's coming a long way, and transport's difficult for them,
then having the treatment in four weeks is highly desirable for them,
and patients would jump at that chance.
There are other influences which are creeping into the UK practice,
and that is with the number of patients that we're treating,
and the propensity for waiting lists to develop,
the idea of treating patients with a seven-week course
and making others wait,
when you could perhaps treat the patients more quickly,
and prevent the waiting list from developing,
that is coming in as well.
So, one always wants to do the best for the patient,
as an individual but also as a group,
so that is influencing various centres.
To date we're fortunate in not being influenced by that at the moment.
The other consideration that you have to take into account
is that if you do start giving the treatment more quickly,
with bigger fractions,
you are more likely to develop late side effects of radiotherapy.
When you give bigger fractions,
after about a year and a half, the body if you like,
seems to remember that it's had radiotherapy,
and the tissues that have received the big dose,
can become more atrophic, thinner, more fragile -
they can develop telangiectasia which are thin fragile blood vessels.
The different treatment fractionations
are being studied to see whether they have the same overall success rate
and the same late complications.
For example, there is a randomised control study in breast cancer
of two different fractionations, in fact, three different fractionations,
looking at the conventional and the shorter ones.
It's finished now and so the patients are on their follow up,
and we will see whether the rates of relapse are the same,
and whether the cosmetic results are the same,
and that will influence whether we move as a country,
towards a quicker fractionation schedule.
There is another trial, the chip trial in prostate cancer,
that is looking at the conventional two-gray per fraction regime
versus a quicker hypo-fractionated regime,
and results of that will be available in many years to come.
But really that's the...
that's the best way of knowing what matters for the patient.
We're all wanting these machines. they're expensive
and the government have paid for
a whole tranche of machines up and down the country,
but we're still limited by both medical physicists,
and also therapeutic radiographers to actually run the machines.
Radiotherapy, I think, in the UK,
could probably develop more quickly
if we had a good number of medical physicists,
because every department in the country really,
is wanting to introduce new machinery,
the latest gadgets and technology,
but there's a cost to that -
it takes time to commission these new machines,
and many departments already
have not got their fill of medical physicists,
so, if a medical physicist
has to take time out of their treatment planning for example,
to commission a... a new linear accelerator,
then the waiting list can grow,
and clearly that's extremely worrying for a patient.