Izzie Stevens finds out she has cancer, specifically Stage 4 metastatic melanoma, in Season 5 of Grey's Anatomy. The storyline unfolds over several episodes:
- In Season 5, Episode 16 ("An Honest Mistake"), Izzie confides in Alex Karev about her diagnosis privately.
- Up until Episode 20 ("Sweet Surrender"), most of her friends and colleagues do not know about her condition.
- She officially reveals her cancer to the rest of her colleagues in Episode 20, which marks a significant moment in her storyline.
The cancer diagnosis is serious, with the melanoma having spread to her liver, brain, and skin, and a survival rate of only about 5 percent at that stage. This marks an important turning point in her character arc and the show overall, impacting her relationships and leading to her marriage with Alex Karev in the same season.
