Having a child with a serious disease can take its toll on an entire family, even one as affluent, adventurous and accomplished as the Fitzgeralds. Teenager Kate is in the late stages of leukemia, and as her health declines, it threatens to become a black hole that consumes them all. "My Sister's Keeper," an uneven but deeply moving adaptation of Jodi Picoult's 2004 bestseller, probes the emotional turmoil of a family whose lives are defined by preventing a daughter's death.

Sara (Cameron Diaz) abandoned her career as a lawyer to manage Kate's care, preparing organic meals, researching treatments, negotiating with oncologists and surgeons for the most advanced forms of care. She's sharply intelligent and tenacious, plotting strategies against her daughter's cancer as if it were a courtroom adversary she could wear down or outwit.

She's exactly the advocate you'd want if you were in peril, bulldozing through all opposition, but her laserlike concentration on Kate's health pushes everyone else into the background. Her firefighter husband, Brian (Jason Patric), is a stoic, supportive afterthought. Their adolescent son Jesse (Evan Ellingson) is alienated and invisible; he takes nighttime bus rides into risky areas of town and no one notices he's gone.

It's 11-year-old Anna (Abigail Bres- lin) who has paid the biggest price. She was artificially conceived as a source of spare parts, a genetically engineered perfect donor for stem cells, blood and bone marrow. As Kate's condition worsens, the family turns to Anna for a kidney transplant. Anna dearly loves her sister (hauntingly played by Minneapolis native Sofia Vassilieva), but she refuses to compromise her own health and files a lawsuit to win control over her own body.

But the film doesn't succumb to courtroom claustrophobia. "My Sister's Keeper" is an insightful family drama, not a bioethics lecture. Director and co-writer Nick Cassavetes treats this potentially soapy material with sensitivity and care, understanding the evolution of families under stress. He casts actors against type (Diaz and Little Miss Precocious Breslin are especially effective in weighty roles).

He honors each character's perspective on the difficult choices they face. Sara's insistence that Kate must be drugged, radiated and cut open as often as it takes to beat her cancer gets his respect. So does Kate's desire to experience life outside the intensive-care ward, even if it has unhealthy consequences. Anna's desire for medical emancipation from her parents' control contains a bit of willful selfishness, but a surprising amount of mature wisdom.

Even secondary characters have intriguing personalities. Alec Baldwin is superb as Anna's principled but self-promoting attorney, and in a rare dramatic role, Joan Cusack gets the humane essence of the judge hearing the case after losing her own child.

The story is something of a collage, overlapping scenes from present and past, telling the story through a half-dozen narrator's voices. It's as if the scrapbook that Kate keeps of her life has come alive onscreen, an evocative and touching effect. The film omits some of the novel's grittier themes and crucially offers a new ending, replacing the shocking twist climax that many readers found melodramatic and contrived.

"My Sister's Keeper" concludes on a redemptive, lyrical note. This is a weepie with heart and brains to spare. Get out your handkerchiefs.

Colin Covert • 612-673-7186