Read a book together about the body. Point out where the cancer is and what is happening physically. With younger children, role play. Act out what is happening to you by using a doll. Use other dolls for other members of your family.
Children often express what they are really feeling in their play.
Encourage your children to draw pictures about the experience of having a parent ill. This is also a good way to express emotions. Select stories about other people who have had cancer and read them with your children. Get together with other parents and families who are coping with cancer. Arrange for your children to meet other cancer survivors.