Finding the right words to say to someone in such a dire situation can be difficult. Merely asking "How are you?" feels funny, and yet saying nothing and pretending that she doesn't have a life-threatening condition seems uncaring.

So what are the right words when you encounter a friend whose cancer has gotten aggressive? How close a friend she is can make a big difference here. Women who are very close can literally say anything and it's going to be all right. They know each other so well that they can speak candidly and without fear that their words will be taken the wrong way. They can ask "How are you?" and then accept an answer back like, "Terrible—my treatment isn't working," and then embark on a conversation that is emotionally profound.

Such direct questioning, however, isn't probably the best approach to take with women who are more acquaintances than friends. Inquire instead about her, as well as her family. Perhaps your kids and hers are in sports together or band practice. Ask her about an upcoming holiday if a date is near when families traditionally gather to celebrate. Keep it light.

I think it's fine, also, to say to a woman in this situation that you'll keep her in your prayers, but ask—such an offer might not feel quite appropriate coming from someone she doesn't know very well. But if it's someone you do know well, saying "You and your family remain in my prayers" can be very comforting.

Sometimes women dealing with metastases are comfortable talking about their diagnosis, health status, and treatment, whereas others prefer not to talk about it at all. This is why you need to know the person personally to determine her comfort level in discussing it.

And one last word of caution—if she tells you any information about herself and her cancer status, she is certainly not giving you permission to now go and tell others.