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Which factors affect the risk of long-term side effects from radiation therapy?
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radiation therapy
External beam radiation therapy (also known as external beam teletherapy, or long-distance therapy) being delivered using a machine known as a linear accelerator.
The development of long-term side effects from radiation therapy is primarily determined by three key factors:
- Tissues exposed: Because radiation therapy is a targeted treatment, long-term effects are generally limited to the specific tissues and organs directly within the radiation field.
- Patient age: Age is a critical factor, particularly for children. For example, radiation exposure can impair bone growth if the growth plate is in the treatment field, or impact cognitive development and neurological function in young children treated for brain tumors.
- Radiation dose: The intensity of the treatment plays a significant role; for instance, high doses of radiation to the pituitary gland or thyroid gland can lead to hormone deficiencies at any age.1
These long-term effects are typically permanent. Additionally, radiation therapy carries the risk of inducing secondary malignancies, which are considered radiotherapy-induced if they occur within the treatment field, possess a different histology than the original tumor, and appear after a sufficient latency period.1