Long-term risks of radiation?

[triplewave]

For anyone who was under 40 at diagnosis and had the option of microsurgery or radiosurgery but chose radiosurgery, how did you justify the potential long term (15+ years from now) risks of radiation to the brain? Half of the surgeons I've talked to have said that this is a major concern (could lead to dementia, cancer, etc.), while the other half don't think it's a big deal.

[PaulW]

Radiation has been around for a long time and they actually do have a good understanding of what happens in the first 20 years. Each persons long term risk varies considerably too. A small tumour needs very little radiation to treat it. So the chance of long term complications for a small tumour are close to zero. A larger tumour needs a lot more zapping and therefore the risk could go up 100 fold for a larger tumour. A small tumour could have a volume of 0.12cm3 while a large tumour could have a volume of 12cm3..
Is the risk 1% for a nasty complication in 50 years... if you had a large tumour... maybe.
Then again, you need to weigh that risk against surgery.

[triplewave]

I found this to be reassuring specifically regarding the risk of second tumor formation:

The chance of second tumor formation was similar between patients having radiation (0.5%) and
surgical resection (0.4%). Patients treated with observation (1.2%) had an increased risk
compared to patients having radiation. They concluded that the short- and intermediate-term risk
of second tumor formation was no greater for VS patients having radiation and that tumor
formation is often coincidental to the radiation exposure rather than casually related.

Source: "The Risk of Radiation-induced Tumors or Malignant Transformation after Single-Fraction
Intracranial Radiosurgery: Results Based on a 25-year Experience " https://sci-hub.cc/10.1016/j.ijrobp.2017.01.004

[ANSydney]

It's important to note that there are secondary tumors (new malignant tumors) and malignant transformation (existing tumor changing to malignant) when reading the article.

The bigger risk is that of malignant transformation. I've had a brief read of the article and will read it again slowly before fully commenting.

I've always held that the chance of a secondary tumor or a malignant transformation is so small that it should not affect your decision. Remember the chance of death from open surgery is 0.5%!

BTW, patients treated with observation do not have an increased risk compared to patients having radiation and I'm surprised significant doctors such as Pollock and Link would make that incorrect conclusion. Let me prepare a proper response and I'll explain why.