Published Monday, 12 November 2012
The brave four-year-old said he will undergo checks to find out if he is in remission from his illness, and also on his heart condition.
He returned to hospital after enjoying some time at home with his family over the weekend.
On Saturday, a fundraising event took place in Belfast city centre which saw a truck pulled up Royal Avenue in aid of little Oscar.
His grandfather, Brian Knox, said the public's support has kept his family going.
"The family has been overwhelmed by the support, it's unbelievable it has been a big help to us because it's very tough times," said Brian.
"We've the support from all over the world has been great, it boosts us on."
Oscar has had a tough time in recent weeks.
He'd made the exhausting trip to Philadelphia for potentially life-saving treatment to counter his neuroblastoma, only for a heart and lung condition to rule it out. And since the little boy's return to Northern Ireland, he's been suffering from abdominal pains.
"He is back in the Royal at the minute and they're gradually treating the condition and he's getting better," continued Brian.
"He got out a couple of hours yesterday and I think he's out a couple of hours today. Just at the minute we don't know what the future holds but the campaign goes on.
"We are raising more money for the next time so he can get the treatment the next time, or some other child, for the neuroblastoma is a very severe cancer."
Oscar has been updating his thousands of supporters worldwide via Twitter, where he has been backed by stars including Westlife and Snow Patrol, footballer John Hartson, boxer Paddy Barnes, broadcaster Jeremy Kyle and many more.
Mr Knox added that Oscar's spirit has kept the family upbeat during the worst of times, and described the youngster as "inspirational".
"He's unbelievable, that's what keeps us going," said Brian. "We find it hard, very hard at times, but you just have to look at Oscar and he is full of beans, always smiling, always comes back with a smile and everybody takes great inspiration from him."
© UTV News