Who do I even have to tell?

Nobody, medically speaking. Your diagnosis is yours, and there is no rule that family, friends or your employer must be told. Some people tell everyone in a week. Some tell two people in a year.

It helps to have at least one person who knows the medical details and can come to appointments, because two people hear more than one. Who that is matters less than that there is someone.

Written by two physicians. Checked against patient information from the US National Cancer Institute and Cancer Research UK.