which cells does radiotherapy kill

i am having radiotherapy. Not worried about it, onc says it kills the fast growing cells and does not harm my breast because they are slow growing ones.

so i have been happily thinking that we cut a lot out and this radiation treatment is going to clear my breast of any remaining cancer.

But i have lots of different types of cancer in my breast at different stages. Does this mean that the radiation only kills the more agressive stage 3 cells that are growing quicker and will leave the slower growing and precancerous ones alone?

O&L, obviously I’m not an expert, but I think I’m right in saying that ALL cancer cells are fast growing when you compare them to our normal tissue cells. So even the slower growing and precancerous cells grow quicker than your normal breast tissue cells.

thats a relief then.

i think radiotherapy blasts everything in its path, but kills the bad cells and the normal ones recover… i had some back pain after my rads and when i told my onc , he said the radiotherapy gets everything and i was just healing afterwards

thanks for bringing that subject up OAL. have been thinking about it myself. i had idc,1.5cm, wle , thankfully clear nodes. 20 rads then 5 boosts. finished 3 wks ago. (and tam 4 5 yrs). i feel great, boob skin all healed up nicely. cant even see the square that was zapped now. my skin and scar are fab cos im sure of the moisturising i did a zillion tmes a day. good luck 2 all! alex xxx

I think I read somewhere that the radiotherapy damages the DNA of the cells, and where normal cells are able to repair themselves the cancer ones aren’t so they cannot reproduce and die off while the normal cells recover and reproduce normally.


I also did a bit of research and found the same info as squeak did. That’s why we have a series of rads treatments on consecutive days over several weeks, by the end of it the cancer cells have had enough (hopefully)!
Interesting to hear that mummysboob can’t even see the zapped square after 3 weeks, mine lasted for many months. Plus then my BC consultant said it was a good idea to get some sun on my scars, which I dutifully did, only to find that the rads square came back good and strong! But it has helped to tone down the scars.
Sarah x

I too, after finishing 3 weeks ago, do not have any sign of the zapped square on my breast anymore. I do, however, have a bad burn underneath my breast which is driving me mad. I’ve tried various creams without success. I have to go past the hospital tomorrow so think I will pop into Radiologoy and see if there is someone who can look at it.

Hiya I’ve had 15 plus 8 boosters, finish tomorrow, my boob is ever so slightly pink.
I do tan very easily, plus I’ve been slapping on the cream very regularly.

Radiotherapy works by disrupting the DNA of cells, so that when they try to replicate they can’t. It’s important to remember that Radiotherapy will disrupt the DNA of any cell that is subjected to it (cancerous or normal), and those cells will not recover - which is why radiotherapists go to great lengths to avoid healthy tissue, and why conventional radiotherapy is quite limited in the areas of the body it can treat.
There is now a type of radiotherapy called stereotactic radiotherapy, which includes such things as Cyberknife, Gamma-knife, TomoTherapy, and Linac, which delivers radiotherapy in a way that avoids damage to healthy tissue, and so it can be used on areas previously regarded as largely untreatable. Unlike conventional radiotherapy, which just delives two ot three wide beams, Stereotactic radiotherapy delivers hundreds of narrow beams of radiation from different angles. Individually, the beams are too weak to cause damage, but when they collide in the centre of a tumour the gray (dose), is multiplied.
Stereotactic radiotherapy is not used on mastectomy sites, because the area is too large (it tends to be used on small tumours).

lemongrove, are you saying that the radiotherapy will zap my normal breast cells and destroy their dna and that they will not recover?? that does not sound right. my whole breast is being targeted not just the tumor site

O&L radiation disrupts the DNA of any cell it comes in contact with, which is why radiologists go to great lengths to avoid healthy tissue. The main danger of subjecting healthy cells to radiation, is that they themselves could become cancerous. However, in some cases it is impossible to avoid healthy tissue (which may be your situation), and under those circumstances radiation is delivered at a lower dose ( a palliative, rather than curative dose). But the problem of giving a palliative dose, is that it may not destroy the cancer, which raises problems because doctors do not like using conventional radiotherapy on the same area twice.
Stereotactic radiotherapy avoides these problems because it is so precise that it does not damage healthy tissue. Also, because it is so precise, it can be used on very tricky areas (such as visceral organs), and at a curative dose (it can even be used on the same area two or three times if necessary). This is why it is so important that the funding of Stereotactic Radiotherapy is sorted out. Hospitals such as Mount Vernon, The Royal Marsden and Barts have this technology, and the National Radiotherapy Implementation Group (a Government advisory group), have recommended that it be funded, but NICE have only just decided that stereotactic rads are an appropriate area for them to evaluate.
A group of us who have been campaigning on this issue, are now setting up a charity to raise awareness of stereotactic radiotherapy, and provide information, advice and support to those who require it … so watch this space.

So, Lemongrove, in theory, it could be used on mastectomy and lumpectomy sites? Or it never would be as the area is too large?

Lemongrove, I think you might be answering a question that hasn’t been asked and so might have added confusion rather than cleared it up (I say “might”, as I don’t have your knowledge of Cyberknife). From the info you have posted on several threads, stereotactic radiotherapy is a very different beast often used against tumours that cannot be operated on surgically, rather than on areas that have been shown, through biopsy of tissue that has been removed, to be clear of a specific cancer mass. OAL is due for the “normal” rads that so many of us get post-surgery, so her question was about the radiotherapy that is administered in that kind of dosage and method.

OAL, I think this is a question that your onc, or more specifically the radiographers that treat you, will be able to answer with relation to the type of rads you’re having. If you’re having boost doses, ask about that too.

Sandytoes - no I don’t think it could be used on an mx site - it is used to destroy small defined tumours and leave the surrounding tissue unaffected beyond a margin of a mm or two. The type of rads that AOL is having, to mop up any stray cells after surgery to remove the tumour, is quite different. The rads would necessarily need to target healthy and potentially cancerous tissue because they don’t know where any cancer cells are, so they have to hit a much larger area. The normal cells will be damaged along with any cancer cells.

Sandytoes, generally speaking stereotactic radiotherapy is only used on smaller tumours, because the beams are narrow. Cyberknife is the most accurate form of stereotactic radiotherapy, because it has a tracking device. During treatment it takes thousands of images of the patient, which are fed back to the computer - which in turn can then predict movement, and make tiny adjustments to the angle of delivery. However, Cyberknife can only treat tumours under 3.5 cm, and it is also limited in the number of tumours it can treat in one go (up to about 5). TomoTherapy, is really an IMRT machine, that can be adapted to become stereotactic, and because of that it can treat larger/more tumours. It is not as accurate as Cyberknife, but it is still MRI guided, and far more accurate than conventional rads.
A machine like Gamma-knife (which people often confuse for Cyberknife), is only used on head and neck cancers.

Thanks Lemongrove. Really interesting. x

OK Choccie, sorry if I’ve confused anybody. I explained how radiotherapy works (i.e, by disrupting the DNA of any cell it comes in contact with), and I thought peeps might be interested in some info about stereotactic radiotherapy - but if they don’t thats fine.
As for the use of Stereotactic: At the moment, stereotactic rads are used on cancers that conventional rads cannot treat, but as it becomes more widely available, it will treat cancers that conventional rads currently treat - only much better.

i feel a bit stupid here… i never questioned what my onc said, and basically he said, you will be having 15 rads to the entire breast and 2 to the scar…it was only afterwards when i had some discomfort that i was told the rads got anything in its path…on my rad breast you can still see the darkened skin in the shape of a big oblong, covering all my breast, and my nipple has gone very pale…some well meaning sole said… the radiation can last for up to 15 yrs i dont know what sort i had… i thought rads were rads…

I spoke to the rads people today while I was there, following this thread, and I can pass on what was explained.

For the sort of radiotherapy most people have, the whole breast and sometimes the nodes are targetted with X-rays. The x-rays don’t “kill” cells (so you won’t be left with a wizzened shrivelled lump of black flesh!) but distrupt the DNA in cells as Lemongrove said, so the cells can’t divide. Normal breast cells don’t do this terribly often so they just tick over, being normal breast cells. Obviously, cancer cells divide as is the nature of cancer, so as soon as a cell that’s been irradiated tries to divide, it dies and it excreted through your urine in the usual way. That’s why cancer cells are affected so much more than normal breast cells.

I was told the term to google for is “radiobiology”, so I’ll take a look at some stage as I find it rather interesting.