Being honest and using simple language is usually the best approach when talking to children about cancer.
Books can help younger children understand, whereas teenagers may want to ask more questions.
Explaining where the cancer is and how it will be treated will help them to understand and ask more questions if they need to.
It may also be useful for teachers, other parents or nursery staff to be aware of the situation. This will help with emotional moods while you are not within reach.
It may help them to reassure them that it was nothing they did that caused the cancer and that there will always be someone there to look after them. It is important to let them process the information in their own time.