Tiredness After Radiotherapy

I understand that radiotherapy can make you very fatigued. Does this last long after the treatment is complete?

In my experience it started midway through the treatment ( I had 15 sessions ) once I upped my fluids it made a big difference ( fatigue can be due to dehydration ) I continued to feel tired for about a week after radiotherapy sessions ended .

Hi @moobloo

Not everyone suffers with fatigue - I did , it started about 3 days after treatment and continued for about 10 days continuously then took about 2 months to go completely . I could still look after myself potter round the house and take short walks.
I was ok during the treatments and drove myself to and from . Also the staff were lovely and the treatments were not at all unpleasant and only lasted a few minutes.

However I’m not sure all my fatigue was all down to radio as I had a lot of family problems at the time not to mention the side effects of Anastrozole which I started taking about 10 days after radio finished. If you were to give me a choice between having another 5 radio treatments and repeating that first month on Anastrozole again even with the fatigue I’d pick radio every time.

The effect of the treatment is cumulative and peaks a couple of weeks after so even if you’re feeling ok don’t try to overdo it during that time. If you do get some fatigue then schedule a rest / nap / relaxation into your day and try not to get stressed about it.
After about 6 weeks I was doing fairly normal activity most days.

Hope this helps
Joanne. X

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I had five straight sessions and the tiredness hit me about 7/10 days later. It lasted a couple of weeks. Good luck x

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Hello all
It is certainly the case that fatigue is the main side effect from radiotherapy and it can be hard to distinguish radiotherapy fatigue from general tiredness for quite some time. I was advised that after six weeks the initial fatigue would subside but that I might have days where I felt it for 18 months. It was explained to me as the body desperately fighting to resist and counter the change in the cells that had received the radiotherapy but after that time it gives up the fight and gives you some energy back!
It’s nearly 2 years since I finished my radiotherapy and I find some days I’m completely wiped to the point of feeling like I’m coming down with a virus but when I wake up no symptoms so I put this down to fatigue and my “new normal”
The advice I had was to be patient and listen to your body
AM xx


I’m not due my radiotherapy yet (18 week waiting list) but have heard that the fatigue is likely to.occur after treatment. I’m an infant school teacher and on the go all day… is this then likely to impact work ? Just having 5 doses

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I had 5 sessions over 5 days. Whilst having the radio it was the travelling that made me tired but after the radio about 2-3 weeks the fatigue really hit me and lasted a couple of months.

I returned to work a week after my 5 sessions. The fatigue was difficult but manageable. Definitely listen to your body and take little breaks where you need them.

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I had 5 sessions of radio in Feb/March 2021 under new regime so more Gs at each session than prev. 15 session regime. I was very fatigued for about 5 or 6 months, improving gradually. I had to accept that I needed help and I found a cleaner for a couple of hours a week and someone to mow the grass. There is a lot to deal with after diagnosis - be gentle on yourself and good luck


I’m too in education! We are all different and all I can say is just listen to your body. There is no linear line. I was working all through my radiotherapy but after my 4/5th session it really hit me

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I had 15 rounds of radiotherapy last year. I was not tired at all. The Radiographers said people are usually fatigued and put my lack of tiredness down to the fact that I walk a lot ! So if you have time and can manage your 10,000 steps a day that might help. I still aim to do that in the belief it is keeping me healthy. The treatment is fine and each session only takes minutes. Good Luck.


I had 30 rounds of radiation treatments. I walked on a treadmill for 40 minutes daily and ate as healthy as I could. I worked from home on a computer for 5-7 hours weekdays. I did take a nap early evening or late afternoon for about 20 minutes. Fatigue was there, but not bad. I think the fact I was walking before my cancer surgery and continued the best I could during the recovery phase. I felt pretty good going through treatments. No burning or side effects. About a few months after treatments I did start an aching around the surgical site. My surgeon said may be scarring and the radiologist said sometimes it’s from the radiation, but usually found in patients that burn. So who knows. Otherwise no problem. I think everyone experiences radiation a bit differently. For me, the side effects from Anastrazole have been worse than radiation. Again, everyone is different. Do the best you can and don’t be too hard on yourself for days when you are experiencing fatigue.

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Thank you everyone xx just playing the waiting game now …

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I went through radiation and I wasn’t really tired from it. I think it’s different for everybody. You will be fine. Hope you are doing well.

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I used to teach, and I had 5 days of radiotherapy in early July. I’d say I had slightly worse fatigue than many, probably due to complicating factors.

Even so, I think would have been able to work through it in a school, based on my experience ten years ago with thyroid related fatigue. Just plan that you might not be able to do much else.

I was okay during. The fatigue kicked in roughly two weeks got better and then a little worse, and now it’s mostly okay. Plan for naps and more staring at the walls than you normally do. Drink your water and listen to your body.

Kelly x

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New to forum today. Desperately seeking comments or narratives.

Start radio within two weeks IF I decide to go through with it (am beyond age 65 and teaching full-time and have scoured the research re. some older women being able to safely go without). Have to do the (five only, I hope!) consecutive treatments while teaching full-on. Surgery was September–clear margins, no nodes taken. Am wondering whether that seems POSSIBLE to any of you who have experience–even though I realize how different each individual is.

Will be on Tamoxifen soon, with or without radiation. No other drug therapies said to fit my situation.

THANKS in advance for any thoughts re. going without RT–or scheduling it and teaching straight through that same week.


I was ok during the week of radio - the Saturday slept for ages. It’s been up and down since - for some reason I’m particularly tired this week, 3 weeks afterwards. I also started tamoxifen, am hypothyroid and unsure which is causing what!

Hi Kelle it is interesting that the fatigue got better and then worse. I’m a bit worried as I thought I was feeling better last week but went downhill again this week! 3.5 weeks after radio. I’m off work thankfully.