"I'm just grateful to have been born at a time when the research made it possible for me to survive. I feel so incredibly lucky to be alive."
Best known for her portrayal of an obsessed fan in Misery, Kathy also opened up in the interview about her battle with lymphoedema.
The debilitating and potentially disfiguring condition was brought on by her breast cancer surgery in 2012 and has left her with excess fluid collecting in her arms.
The Titanic star has to wear a compression sleeve to minimize swelling.
The American Horror Story actress has previously shared why she was not keen to go under the knife for a reconstruction.
She told Coping Cancer magazine in 2014: "At the last minute I decided I was feeling so good that I didn't want to go back to surgery, to bed rest, to being on pain medication.
"I realized that I already had what I wanted most, which was to be happy, have energy, work, be with friends, and live life."
In the latest interview, it is clear her position still hasn't changed.
Bates has lymphedema as the result of doctors removing 19 lymph nodes during her breast cancer surgery.
She told WebMD how she remembers "getting hysterical" in the hospital when she noticed strange pains in my hands and discovered that her arms were swelling.
She knew right away what it was as her mother had had a radical mastectomy and also suffered from from the same condition.
The body's lymphatic system transports a clear watery fluid called lymph, which contains infection-fighting white blood cells, throughout the body.
When this fluid doesn't drain normally - which can occur when lymph nodes are removed or damaged after cancer surgery - swelling can happen.
As many as 10 million people suffer from lymphedema in the US alone.
There's no cure for lymphedema, but congestive lymphatic therapy (DLT) can control systems.
DLT includes compression bandages, skin care, exercises and specialised massage techniques.
Kathy said she felt "like a boa constrictor" with her arms in the tight sleeves, which she had to use twice a week.
She said losing weight has has helped considerably, but she still has to control her salt and alcohol intake, stay out of the heat and avoid picking up heavy items or he symptoms can emerge,
Today, Bates manages the disease with regular visits to her doctor.
She has since become a spokesperson for the Lymphatic Education & Research Network (LE&RN), so she can help others suffering with the condition.
She has also spoken out about the need for doctors to be better educted about lymphedema.
She said she has been told by doctors associated with the network that in four years of medical school "future doctors spend a total of 15 to 30 minutes on the lymphatic system".
