Not too many decades ago, some illnesses were never discussed openly, even among family and friends. Tuberculosis was rarely mentioned in front of other people, for example. And any mention of cancer was made in hushed tones more suitable to talking about bubonic plague. Cancer gradually became the most feared word in the English language. It still is. Today, many people remain reluctant to talk about it, even though it is now a rather common disease and often a curable one.
How open you should be about the fact that you have cancer or about how your treatment is going is entirely up to you. There is no single "right" way to talk about it. There are no "right" words to use. Like everyone else, you will have to find your own comfort area and the words you're most comfortable using. If you would rather talk about your "malignancy" or "tumor" or "growth" or "lump" or "problem" than keep using the word "cancer" all the time, so be it.
Deciding Who to Tell Some people prefer to keep their cancer a very private matter, not telling anyone outside the family. One person in our experience has had cancer for 19 years and no one knows but her husband and her daughter, now age 21. The cancer started in 1971 with breast cancer metastatic to her liver and bones. Yet she works, she runs track and is active in the community. One of the reasons she has survived is because she is living with her cancer. For her, this approach is a very positive one. She wants to forget about it and get on with her life.
