Each year, approximately 20 million people receive a cancer diagnosis. At that time, a patient usually learns their cancer’s stage, which is typically a number ranging from one to four. While staging is designed, in part, to help patients better understand what they’re facing, the number can be confusing. So, what do cancer stages actually mean? Hyunsoo Joshua No and Trudy Wu explain. Lesson by Hyunsoo Joshua No and Trudy Wu, directed by Jess Mountfield.