The 61-year-old head judge revealed is set to undergo further tests at King’s College Hospital in London on Friday, after viewers spotted a lump in her armpit during the BBC dance show.
Ballas was asked by Good Morning Britain's Richard Madeley if she was worried, and admitted she was avoiding the question.
She added: "I try not to worry because it's so busy and there are other people relying on me.
"I just keep moving forward. Don't dwell on it because it will be what it will be."
The dance teacher revealed she had visited her doctor after being contacted by several concerned viewers about the lump under her arm, and her blood tests had highlighted some alarming hormone levels.
Ballas said: "The last two weeks, it has been like a whirlwind with everything else I've been doing.
"I was doing a Paso Doble move, put up my right arm and one or two people got in touch and I kind of ignore. And then there was about 11 people getting in touch so I thought, 'No I better go to the doctor'.
"I went off to see my doctor, she had a little feel around and she couldn't feel anything but she had some past blood tests from a few months before. I hadn't gone back for the results - my fault - and she was alarmed by them.
"She redid all my bloods last week and she was alarmed by the testosterone levels, the lack of oestrogen levels and other things that were going on. So I'm going off for my test on Friday at King's College.
"With me, the NHS has been really, really quick. I normally find out within a week to 10 days, I can get the results and then my doctor can go from there."
Ballas - who contracted coronavirus in March - underwent tests earlier this year after doctors discovered a "cyst or tumour" between two bones of her shoulder.
She told GB News in June: "I got the Covid virus and then they found a ganglion cyst or a tumour in my shoulder.
"I am going backwards and forwards to the hospital all the time. I feel I seem to be getting sicker by the minute. I can't seem to get up and out. It's something between two bones and they are not really sure what it is yet.
"They have done the dye and the MRIs plus this and that. I get the results in a few weeks. The gentleman seems to think it will be fine but, still, it is worrying."
The former dance champion had her DD breast implants removed in 2019 after discovering a growth on her chest.
There is a history of cancer in Ballas's family. Her mother Audrey was diagnosed with colon cancer in 2019, and her grandmother and aunt have also battled the illness.
Watch: Shirley Ballas shows off injured hand after kitchen accident