Fifteen years ago, Mara Buchbinder and colleagues came up with the concept of the “patient in waiting.” The concept described a new category of patients created by cutting-edge testing for conditions that may never appear. The patient in waiting was, quite literally, someone who was waiting to see if they would become ill.

Mara's husband, Jesse Summers, was diagnosed with metastatic colon cancer in 2021. It went into remission — but earlier this year, a test searching for disease recurrence came back weakly positive, suggesting that the cancer might be back but might not be. It put Jesse and Mara into a sort of limbo as they waited to see what the result meant.