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What is leukemia?

Leukemia is a type of cancer that affects the blood and bone marrow. It can happen in children and adults. The cancer begins in a cell in the bone marrow. The cell undergoes a change where it grows and survives better than normal cells. Over time, the leukemia cells crowd out or stop the development of normal cells. The rate at which leukemia progresses and how the cells replace the normal blood and marrow cells are different with each type of leukemia.
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In Canada, there was an estimated 6,800 new cases of leukemia in 2025.

Why the type of leukemia matters

There are four major types of leukemia. Within each type of leukemia, there can be several subtypes. The treatment for leukemia varies significantly according to the type or subtype and whether it progresses quickly (acute) or slowly (chronic). You may find that learning about your diagnosis once you know the type and subtype of leukemia involved will help you better understand the disease and its treatment.

Four main types of leukemia

Resources on Leukemia

Get the information you need, in the format that works for you - from symptoms and side effects to treatment options and next steps.
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Other types