TOWSON, Md. — Two days into a long-dreamed-of family vacation to Italy in August 2013, my wife, Ronna, became nauseated, unusually tired and short of breath. One of the great non-complainers in American history, she insisted that it was no big deal and valiantly tried to join in on various outings in the Italian countryside. But, after a few increasingly difficult days, even Ronna knew that it was time to go to the emergency room.

In a small hospital in Tuscany, doctors identified the apparent source of the problem: a pericardial effusion, or a buildup of fluid around the heart. Ronna was transferred to a larger medical center in Arezzo, where a pericardial tap was performed. Immediately afterward, in a scene that still plays on a loop in my mind’s eye, the hospital’s chief of cardiology informed me that, while the fluid was gone, he was quite sure that Ronna had lung cancer.

A few weeks later, when we were back home in Maryland, doctors at Johns Hopkins Hospital confirmed his suspicion: My healthy, active, 48-year-old, never-smoker wife had Stage 4 non-small cell lung cancer.

Over the next two years, Ronna underwent several rounds of grueling chemotherapy and, when the cancer spread to her brain, several rounds of radiation treatment. She also took part in a clinical trial at Johns Hopkins for Opdivo, an immunotherapy drug made by the pharmaceutical company Bristol-Myers Squibb. Briefly stated, immunotherapy is a recently developed, highly promising treatment that helps a person’s immune system identify and attack cancer cells. But it did not work for Ronna, and last Sept. 25 she died as her parents and I held her hands and whispered in her ear.