Ghadie told The Mirror that the storyline echoes her personal experience of finding a lump after the birth of her daughter.
"It was really scary," said the 30-year-old. "[Freya] was only three months old when suddenly I came across a lump on my breast that was like a really hard pea.
"I went to the doctor straight away and I was hoping she was going to say 'Oh, don't worry', but I was very frightened when instead she said: 'Actually we don't want to get caught out with things like this, you need to see a specialist.'
"To hear that was terrifying... in those few hours while I was waiting, all sorts of horrid things went through my mind. You worry so much."
Ghadie was later told that the lump was benign and a result of hormone fluctuations.
"I was so relieved," she said. "I am so glad I did get it checked out and it's made me very aware now. I check my breasts on a regular basis. It's so important to."
The actress revealed that her own experience made her determined to portray Maria's scare as realistically as possible.
"Because it's so sensitive, we worked with Macmillan on the storyline as we wanted to get it right," she explained. "I know myself how it feels and how scary it is and I think a lot of women will identify with what Maria has to go through... I hope people will feel I have approached it sensitively.
"Maria goes through very similar emotions as I did but it is far worse for her as she doesn't get the results back so quickly and she really stresses out about it."
As well as dealing with her health scare, viewers will see Maria being forced to confront her emerging feelings for her best friend Marcus (Charlie Condou), who is gay.
"Marcus finds Maria crying about her breast cancer scare and, eventually, he manages to find out what is wrong," said Ghadie.
"She is dating Jason Grimshaw [Ryan Thomas] but it's Marcus who she wants to accompany her to the hospital.
"They are good friends but the lines start to get blurred. She knows he is gay but she can't help her feelings for him.
"On paper, Jason is the best choice for her but she can't stop her feelings for Marcus."
Ghadie said that she was "completely shocked" when she first learnt about the storyline and was initially reluctant to film the scenes.
"I found it weird and I didn't want to do it at first. It is such a sensitive area and it was completely unexpected," she explained.
"But after a while, I realised this does happen in real life and I do think it is a good issue to tackle. It will get people talking and I know some people will be pleased they do get together. People stop me in the street and ask me why Maria isn't with Marcus."
When asked about how the story develops, Ghadie admitted that the outcome "affect[s] Jason heavily".
"The whole street turns against [Maria and Marcus]," she said. "They are happy initially, but long term, I am not so sure."
She added: "With Maria, there is never a happy ending. At some point I will be crying again!"