CLL is the most common form of leukaemia, and is rare in people under the age of 40, mainly affecting those over 60 years old. CLL is more common in men than in women. CLL tends to develop slowly, and many patients will not need treatment for months or even years. The average survival rate for CLL is 10 years, but this figure may be distorted by the fact that many people diagnosed with CLL are well 0ver 60 years old.
Cancer Research UK suggests that: "On average 44 out of 100 men (44%) and 52 out of 100 women (52%) will live for at least 5 years after being diagnosed."
Elgin tells the narrator that Louise has had leukaemia for 'About two years'.
He also tells the narrator 'It's rare', suggesting that Louise is under 40 years old.