With radiation therapy, could some of the radiation used cause new mutations in non-cancerous cells that are near the tumour that is being irradiated? If so could these new mutations lead to new cancerous cell colonies (which might later metastasize)?


1 Answer 1


Yes, this can happen, although the risk is low. The problem is that some tumors need to be irradiated since the cannot be operated (this is true for some brain tumors). Here the radiation therapy is the therapy of choice. The effect of the therapy is that the tumor cells get a high radiation dose which either kills them or drives them into apoptosis.

The problem the irradiation is that you will always affect healthy cells, of which most will die. This causes some of the negative effects of the radiation therapy, but it is also possible that a healthy cell receives a dose which is "only" damaging and causes a secondary tumor. Here a benefit analysis needs to be done to see if the benefit from the therapy is woth taking the risk of acquiring more damages. See the references for some more background.


  1. Long term side effects of brain tumour radiotherapy
  2. Second Cancers Caused by Cancer Treatment
  3. Therapy-Related Secondary Cancers
  • $\begingroup$ I thought the apoptosis mechanisms in a cancerous cell have malfunctioned or are damaged ( that's why a cancer cell can't be shut down by its own 'self-destruct' mechanisms) so if a cancer cell is 'killed' by a high dosage of radiation how does this happen? $\endgroup$
    – 201044
    Dec 27, 2014 at 3:02
  • $\begingroup$ DNA double strand breaks, damage to proteins or the cell itself due to the high energy and so on. $\endgroup$
    – Chris
    Dec 27, 2014 at 11:03
  • $\begingroup$ How likely is a high dose of radiation going to cause DNA double strand breaks or damage to proteins or damage to the whole cell and so on regarding any type of cells in the high dosage 'path'? This sounds a lot like some sort of disintegration ray gun you here about in science fiction stories. How long has radiation therapy been used? 50 years? $\endgroup$
    – 201044
    Dec 28, 2014 at 2:57
  • $\begingroup$ Has anybody lived for 10 years after their last 'set' of radiation doses? $\endgroup$
    – 201044
    Jan 10, 2015 at 7:24
  • $\begingroup$ If radiation therapy can lead to new mutations but the risk is low..; how does anyone know if the risk is low as cancerous cells are hard to detect ,probably harder to detect when metastasizing. Even when a new colony of cancerous cells coalesce they.re hard to detect. So how is it determined if the risk is low? $\endgroup$
    – 201044
    Mar 16, 2015 at 4:26

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