Kim has already written much of what I was going to say.
What to say to someone who has been diagnosed with stage 4 cancer. Just let them know that you are available when and if they want to. Ask the person with cancer if they would like to talk about the experience. If its not you probably shouldnt say anything to the person with cancer.
You might say in a caring way I heard whats happening and Im sorry You may feel angry or hurt if someone whos close to you didnt share the news of a cancer diagnosis with you right away. It is better to say I dont know what to say than to stop calling or visiting out of fear. You could ask the person who told you if its public information.
There are really only two things that need to be said to someone you love facing cancer of any stage. You can express your support by saying Please let me know how I can help. Its imperative that you show that you are there to support and help in any way you can.
There is no right or wrong way to feel. These days many people are cured of cancer or are able to live with it for many years. I was told I had about a 5 chance of surviving for as long as I have.
The worst you can do is to say nothing. Stages are used to describe the spread of solid tumours like breast bowel or lung cancers. If the cancer is advanced we have more information to support you.
The stage of a cancer describes how far the cancer has grown and spread at the time of diagnosis. Here are some things you can say to help show your care and support. For example someone living with stage 4 lung cancer doesnt want to hear someone with a stage 2 breast cancer say I understand how you feel Because they cant.