# Second cancers after radiotherapy

Source: https://onco.cc/terms/second-cancers-after-radiotherapy/  
OnCo record `second-cancers-after-radiotherapy` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Radiotherapy can itself cause a new cancer in the treated area, typically ten to thirty years later. The risk is small for most adults but matters greatly for children and young adults.

## Summary

Radiation-induced second cancers include sarcomas in the treated field, breast cancer after chest radiotherapy in young women (as in Hodgkin lymphoma survivors), thyroid and brain tumours after childhood treatment, and leukaemias. The risk rises with dose, volume, young age and genetic predisposition, and is one of the strongest arguments for proton therapy in children, for avoiding radiotherapy where equivalent alternatives exist, and for the lifelong surveillance built into survivorship care.

## Fields

- Kind: Term
- Last checked: 2026-09-16
- Tags: radiation-wave1

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Radiation-induced_cancer
- Wikipedia: https://en.wikipedia.org/wiki/Radiation-induced_cancer

## Connected records

- cancers: [Childhood cancers (all types)](https://onco.cc/cancers/childhood-cancers/), [Hodgkin lymphoma](https://onco.cc/cancers/hodgkin-lymphoma/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/)
- technologies: [Proton therapy](https://onco.cc/technologies/proton-therapy/), [Survivorship care and late-effects surveillance](https://onco.cc/technologies/survivorship-care-plan/)

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