Question:
Just a simple question:
If too much radiation from the sun is known to cause Cancer
then does the radiation given to Cancer patients also cause
Cancer? If not why not, if so how long would this take? I
am just wondering if radiation could be the cause of
breast Cancer spreading to the skin (metastatis)?
Answer:
Certainly a good question. Technically, radiation does not "cause"
cancer, but it can increase the likelihood that you get cancer.
Exposure to radiation has never caused any new effects, but it
enhances the probability of seeing those effects.
So you can get skin cancer whether or not you are exposed to the sun,
but you are more likely to get it if you are exposed to the sun.
Similarly, the radiation given as cancer treatments increases the
likelihood of other cancers. However, 1) this increased chance is a
rather small increase, and 2) the results are typically going to be 20
years (or more) after treatment. (Even exposure to the sun has its
most damaging effects 20 years down the road).
In this case, I would have to bet that the skin cancer was caused by
the breast cancer, not the treatment. There is probably a very small
chance it was the other way around, but a much better chance that the
skin cancer came from the breast cancer. In general, there is no way
to tell what caused a particular case of cancer.
Sorry if that sounds a little vague, but I don't think there is a
better answer.
