The Daily Mirror confirmed Sladen's death, but did not say where she died, what kind of cancer she suffered or how long she fought the disease.
The Liverpool native is best known for her work on the iconic TV series "Doctor Who" and its spin-off "The Sarah Jane Adventures."
She also appeared in "Z-Cars" and "Coronation Street."
"Lis was funny and cheeky and clever and wonderful," the Mirror quoted "Doctor Who" creator Russell T. Davies as saying. "The universe was lucky to have Sarah Jane Smith; the world was lucky to have Lis."
Sladen is survived by her husband, actor Brian Miller, and daughter, actress Sadie Miller, the newspaper said.
Notable deaths of 2014 [PHOTOS]