On April 5, 2005, Jennings informed viewers through a taped message on World News Tonight that he had been diagnosed with lung cancer, and was starting chemotherapy treatment the following week.
Pada 5 April 2005, lewat rekaman kaset video, Jennings memberitahu pemirsa World News Tonight bahwa dirinya menderita kanker paru-paru, dan akan menjalani kemoterapi mulai minggu berikutnya.