I have my first planning appointment tomorrow for radiotherapy. I had a LWE and ws told that although the DCIS was very aggressive they managed to remove it all. They also said that by having radiotherapy it will decrease the chances of it returning by 50%. But is the % of it returning? WHy have radiotherapy on healthy tissue? Has anyone else asked these questions? My gut feeling says not to have it but everyone around me says I must. I feel very confused.

Hi there
I have my first session of Rads today, following a WLE for DCIS. Don’t know the answer to your % question, the comment my onc made was that the radiotherapy was to “sterilise” the remaining tissue, to make sure any affected cells remaining are destroyed.

It seems to be standard treatment for DCIS post WLE, but if you have questions, is there anyone at the clinic you can discuss your feeling with?

Let us know how you are, and I hope you can get the information to put your mind at rest,


Hi Slowrunner

You would need to ask what the risk of it returning would be if you didn’t have the radiotherapy. If that risk is, for example 2%, then the rad treatment brings that down to 1%. If it is 90% then the rads bring it down to 45%. In the latter case, you clearly get a marked improvement in the risk. My onc never spoke about percentages (my tumour was invasive ductal, so different to yours), and I never asked. I just knew that in my case radiotherapy was the most sensible route forwards. My understanding is that, though they remove the tumour and a good margin, there my be stray cancerous cells outside of that margin. The radiotherapy then attacks all the cells in the targeted area (and they do treat the whole breast area in a rectangle from below the breast), but healthy cells are able to recover, and cancerous cells not, so that any cancer cells lurking in there get destroyed. I just wanted to take any treatment they were offering to give me as good a chance as possible of clearing it.
Good luck with your treatment
Phili x