Published Sunday, 28 October 2012
Wee Oscar has arrived back in Belfast. (© Family photo)
Little Oscar travelled on Saturday by air ambulance stopping via Canada and Iceland.
"Flight was good and all is well," the family wrote on Twitter.
Oscar's mum Leona thanked all the ground staff and ambulance crew who greeted them at Belfast International airport.
The family said the trip to America had not gone the way they had wanted, but that they were "pleased to be home safe and well".
Oscar had travelled to Philadelphia for a potentially life-saving treatment for his neuroblastoma, but that was ruled out after an issue was discovered with his heart.
His condition worsened when he suffered another setback in the form of a collapsed lung and he was moved to intensive care.
The Knox family had revealed that doctors had told them to "prepare for the worst", and had said their private goodbyes to their brave little boy.
We felt in control when we worked hard to raise that money and buy him his life back, we could do that.
After Oscar was moved out of intensive care on Wednesday, his family expressed relief that he had improved enough to be able to travel back to Northern Ireland.
Leona wrote in their blog they were "elated" that Oscar has recovered from his critical condition, but that now they feel out of control of their situation.
"We feel lost - we don't know where this is going, more than ever we don't know what the future holds. And we feel defeated - we were cheated of our chance to make Oscar better, once and for all. These statements may not be factually true, but they are absolutely what we feel," she said.
Oscar suffers from stage four neuroblastoma - an aggressive childhood cancer which could kill him. The disease causes tumours to develop, in the stomach, spine, chest and neck, but can also spread to other parts of the body.
His parents were hoping he would receive immunotherapy, which could have given him an extra chance of survival.
Despite the setbacks, the Knox family have said they will continue to fundraise for Oscar and are considering the next option for his treatment.
© UTV News