Leukemia was a type of cancer.
George Smithers' son died of leukemia in 1987. (PROSE: Invasion of the Cat-People)
Thomas Bruce found evidence in files he had stolen from UNIT that his son's leukemia had been caused by his ex-wife's exposure to Nedenah technology whilst she was pregnant. (PROSE: The Devil Goblins from Neptune)
Zoe Blake's daughter Sophie died of leukemia at the age of one. (AUDIO: Dead Man's Switch)