In a post on the Coronation Street website, the actress explained that she found a lump in her breast while preparing for a storyline in which her character Sally Webster has the disease.
"If I had not been researching this storyline I may not have discovered the lump in my breast and had it looked at so quickly," she said.
"As a result of the early diagnosis, my treatment has been successful and I am able to return to work next month. This storyline could very well have saved my life."
Whittaker filmed the Christmas Day scenes in which Sally tells Kevin (Michael LeVell) that she has cancer while she was waiting for her own test results. She continued working when she started treatment, but the storyline was altered so that she could recover from six months of chemotherapy and radiotherapy.
The actress has now revealed that she plans to organise fundraising campaigns for The Genesis Appeal and The Christie Hospital in Manchester and added: "I also want women to know that the sooner you start treating this disease the better."
She thanked her friends, family and colleagues and continued: "The media should also be praised for allowing me to go through my treatment and recovery in private and out of the press spotlight."
Whittaker went on: "I am now looking forward to getting back to Coronation Street and working alongside Genesis and The Christie."
> Corrie raises breast cancer awareness