Brooke Duncan, from Lossiemouth, Moray, had a tumour almost the size of a 10p piece growing in her eye.
There were fears the youngster, who went for a routine eye test after complaining of headaches, would need her right eye removed and months of gruelling chemotherapy. But tests have revealed the rare childhood cancer, retinoblastoma, has regressed.
Her mother, Samantha, 27, said: "At the clinic [where she was tested] they said it can happen but they had never heard of it.
"I still can't get my head around the fact that cancer can just stop. It's a miracle.
"She really is one in a million. She's an enigma."
The cancer itself is rare, with only 50 children a year diagnosed with it in the UK.