32 – Palliative Radiotherapy – what does it do?
14 Dec 2021
Now I know how a ready meal feels. Cook on full power for 4 minutes and then rest for one minute.
I’ve now finished my fifth and final (for now?) fraction of Radiotherapy. So that’s been one treatment a day for five days. As I mentioned in my previous post, there’s no mask for body positioning in the treatment machine (LINAC), just a small tattoo on my chest.
Each day, I’m positioned on the machine and then the radiologists use lasers to ensure my body and the machine is in exactly the correct position. Then I must lay perfectly still for a few minutes as though my life depends on it. And to a great degree, I suppose it does!
I have to say I’m pleasantly surprised that the side-effects are not so bad at the moment – certainly when comparing with the extremely tough treatment to my throat last year. This treatment is really to ease the pain in my back, that’s been caused by the tumours increasing in size.
So, they are hopefully shrunk a bit in size, but my understanding is that it’ll be a few weeks before the full effects are known.
I’ve also had the time – and inclination – to read up some more on what radiotherapy does and what these treatments are given in ‘fractions’, rather than one good ‘zapping’ – so to speak. When I say ‘read up’ I really mean ‘skim read’ of the bits I can understand.
So here goes:
It starts off with the billions of cells that we have in our body. Normally they ‘just work’ and keep all our body working in tip-top shape. Different types of cells in the body do different jobs. But they are basically similar. They have our DNA which generally controls how the cells behave.
Cells come and go. They make copies (reproduce) in an orderly and controlled way and are needed to keep the body healthy. Sometimes they get damaged, and our body has amazing repair teams that can fix cells very quickly and get them good as new.
BUT, some cells get confused by instructions from our normal DNA and they start reproducing (mutating) in a disorderly way and become uncontrollable.
In the worst cases, they can’t be fixed by the repair teams. These worst-case mutated cells can become ‘cancer tumours’
Of course, there are a number of treatments to either kill-off the cancerous cells, or at least hinder their growth. These range from chemical therapy (chemotherapy) to radiation therapy (radiotherapy) and even newer treatments such as Immunotherapy.
I’ve also spent the past few weeks on my own self-administered treatment of Beerotherapy. I’m finding that high intake doesn’t actually control the tumours, do I do forget about them for a few hours. Treatment will continue for as long as I can get to the pub.
Anyway – back to radiotherapy!
The machine that I refer to is a medical linear accelerator (LINAC). I wrote an article on this last year here
It uses extremely high-power energy beams - let’s call these micro-bullets – moving at the speed of light and accurately aimed at the tumours. They’re ‘fired’ from outside the body and because they’re so minutely small and incredibly fast moving, I don’t feel anything while the treatment is being done.
Inside my body however, a number of things begin happening.
First, obviously the micro-bullets are also damaging good cells that are adjacent to the tumours – but my body’s repair teams get straight to work on repairing these. The really clever bit is that the cancerous cells that are getting blasted are not able to repair themselves anything like as effectively – and so bit by bit they become reduced or sometimes destroyed.
And this bit-by-bit thing is helped by what the medics call ‘fractionalisation’.
Which means that instead of one single dose of energy – in my case 20 Gy (grays) of energy (equivalent to around 200,000 normal chest x-rays) is given to me in five fractions of 4Gy per day. In this way my healthy cells are being repaired 24/7 and ready for the next treatment.
An analogy (admittedly not a great one) is to consider a car with four road tyres and a spare in the trunk. If the driver was unlucky enough to have a puncture in each – it would most likely to be less disruptive to have one puncture each day and repair it, rather than five punctures in the same day.
All the while, the cancerous tumours are in big trouble, because they don’t have the efficient repair teams to fix themselves.
So, fractionalisation is far better for the body. Of course, not all the healthy cells repair overnight – or even over days or weeks. Some of these also get damaged beyond repair and this becomes what we know as side-effects from the treatment.
And unless I’m one in a billion – I’ll feel these side-effects over the next few days, weeks or even months.
Which leads me nicely towards the holiday season. No more treatment until at least mid-January, when I see Dr Grant again and find out what comes next.
And that leads me nicely in to wishing you a very happy Xmas and a peaceful and prosperous New Year, wherever you are in the world.
Take care
Woz x