That's why King Charles' family doesn't reveal which cancer he has. The public does not know what type of tumor it is.
All that is known is that the new illness was discovered as part of Charles' recent treatment and the cancer has nothing to do with the prostate. When Buckingham Palace announced Charles' prostate treatment, it was to raise awareness, as the subject is taboo for many men. The British royal family followed the same calculation when Charles was diagnosed with cancer. According to this, “extensive speculation about treatment and prognosis’ should be avoided.