What is the theme in At the Cancer Clinic by Ted Kooser?

Illness is a major theme in the book. The woman described in “At the Cancer Clinic” is clearly at odds with her body. She does not have the strength to walk on her own, struggling with each step. The narrator describes her as staring at her feet as she walks, as if they are independent of her and she is interested in what they are doing. Her body is not under her control.