It made me wonder, thought, what would have happened if Kate had been healthy. […] Certainly, I would not be part of this family. (1.1.4)
Anna's whole existence happened because Kate was ill. It's a weird situation to be in, kind of having to be grateful that your older sister has cancer.
[The nurse] removes the needle, and sticks Kate again, who howls even louder. (1.3.34)
"Howls even louder" are just three words that cannot describe the pain Kate must be going through… or the pain Sara feels at having to watch her daughter suffer.
My sister's in pain, and I'm relieved. What does that say about me? (2.1.21)
Anna is too young to know the term schadenfreude, but that's not what's happening here—Anna is just glad that her mother is distracted, and that this takes her attention away from Anna after Anna files the lawsuit. (Which is weird, because isn't attention what Anna really wants?)
I find myself staring at the goldfish. Bright as a penny, he swims in circles, happy to be going nowhere. (4.3.18)
This is a good metaphor for Kate's illness. They cannot cure her, not matter what they try, they just circle around and around the inevitable.
"It's only a little stick," the doctor promises, exactly the wrong words, and Anna starts thrashing. (4.3.80)
Kate isn't the only one suffering because of her illness—Anna has to suffer through pain and fear of pain when she donates blood.
This is the moment I would have had with [Kate] when she got her period; will she live long enough for that? (5.2.8)
Unless it's Carrie, the whole first period thing is a critical moment in a lot of coming of age stories. Unfortunately, in this book, it's not a period Kate's having—it's severe hemorrhaging. There's both pain and sorrow happening here, because the hemorrhaging could lead to death.
Of course Anna should be honored for donating her bone marrow. Of course she deserves recognition. But the thought of rewarding someone for their suffering, frankly, never entered my mind. (5.3.116)
Sara doesn't think she should reward Anna for her suffering because saving her sister's life should be its own reward, we guess. Kate's reward is getting to live. Anna's is… a little more nebulous.
"Where's the one-liner? Or is it too hard to joke about something that hits so close to the bone? You back away every time someone gets close to you?" (9.1.72)
Picoult will not rest until every character is miserable, and Campbell and Julia's relationship is a source of suffering for them both. His defense mechanism is to run away, and while this saves him some pain, it causes Julia more.
Life isn't nearly as stable as we want it to be. (9.6.12)
Okay, maybe everyone in this book does have an illness. It turns out that Campbell is epileptic, which happened after he was in a sudden car accident. Disease comes out of left field and affects everyone, not just the sufferer.
There should be a statute of limitation on grief. (Epilogue.1)
There's no end to suffering for the Fitzgerald family. Kate's cancer is cured (as far as we know), but they will mourn Anna's death forever.