The six-year-old, from Blackhall Colliery, in the North East of England, has terminal neuroblastoma.
His family has now confirmed that he is receiving palliative care at home ahead of a course of radiotherapy which aims to help him be comfortable.
Groups across Yorkshire have been taking part in fundraising events to support Bradley's fight.
A statement posted on the Bradley Lowery's fight against neuroblastoma Facebook page said: "Sorry for the no updates everyone, I've been trying to process the information myself.
"Bradley had a scan on Monday and it showed what we feared.
"Bradley's cancer is spreading at a very fast rate and he has now got lots of new tumours including in his lungs.
"The lump that was causing pain was originally thought to be a abscess has got bigger and they now believe it's a tumour. We are heartbroken this is happening so fast.
"Bradley is now receiving palliative care at home. He is going for radiotherapy at the end of this week and next week but this is to control the pain in the hope we get him comfortable.
"Lots of people keep asking how long has he got to live? I can't answer this as we don't know all we know is it's not long."
Hundreds of thousands of pounds have been raised for Bradley's treatment during his battle with neuroblastoma.
The statement on the Facebook page added: "We have had messages asking where is the money going that has been raised.
"Please rest assured that all funds that have been raised for Bradley's treatment are going to be put into the Bradley Lowery Foundation charity.
"We are in the process of setting this up and further details of what our aims and objectives are will be published in due course.
"What I will say though because of all the support we have received from you lovely people we are now in a position to be able to help a lot of children.
"Thank you to everyone."
Bradley's story has touched the hearts of people around the world.
The young Sunderland AFC fan has been in the spotlight of media around the world, and has struck up a close friendship with Black Cats striker Jermain Defoe.
Jermain attended the youngster's sixth birthday party last week along with Sunderland team-mate Vito Mannone.