Logan and Regan Skinner, now six, developed the disease in 2012 after their skin started to go yellow and began bruising easily.
Both were diagnosed with Acute Lymphoblastic Leukaemia which attacks the bone marrow, progresses rapidly and requires urgent treatment.
Doctors put them on an intensive course of chemotherapy course this year which Logan has ended and Regan is due to finish next month.
“In the beginning, doctors said it was an 85% chance of survival, but the chance of relapse is higher in the first years of treatment,” Mum Casey Skinner, 25, from Lincolnshire said.
“Because they are identical twins, they were at a higher risk.
The boys will now have regular checks including blood tests every four weeks for the next three years. After that they will have yearly checks for the rest of their lives.
Logan, who is six minutes older than his brother, first became ill aged two. Skinner immediately took him to doctors who diagnosed him with the disease in August 2012.
During intensive treatment, he developed septicemia.
Skinner, who lives with her partner Darren, 24, and his two sons, said “One of the worst moments was when Logan was diagnosed with septicemia.
“I just remember when I took him into hospital and when you see the nurses panicking and they are screaming for the doctors. We thought he might die.
“Luckily they got him straight on treatment that’s when you realise how serious it is.
“You think it won’t happen to me or my kids and then you realise that you are not invincible and that’s so scary.”
The disease put a burden on the family, which was doubled within a year when Regan started bruising easily too.
Skinner, who became pregnant with the pair aged 18, said: “Regan had different infections for example in the ear and then I noticed that he was bruising a lot.
“I was playing with him one day, as he was swinging between my legs he hit his face and the bruise came up straight away.
“The next morning he was bright yellow and I thought he may be anaemic - it turns out he was anaemic but that was due to the leukaemia.”
That day, the doctors compared the twins’ skin colour and sent Casey and Logan straight to Pilgrim Hospital in Boston, Lincolnshire.
Skinner said: “Regan wasn’t unwell when he was diagnosed but he had got an identical bruise to Logan.
“I went to get him tested and they said he had leukaemia too, so I had to go to the Queen’s Medical Centre hospital in Nottingham to get that confirmed as well.”
Skinner continued: “They both had to have a test to see how high risk or low risk they are. Logan was high risk so he had to have a more intense treatment.
“He was really bad - it made him really ill. I remember one day as soon as they pressed the go button on the chemotherapy he was so sick everywhere.
“I remember saying if Regan does get it I won’t be as scared. It’s not just life or death, you have to sit in a big hospital and I thought second time round I would be okay dealing with it.
“When I was told Regan did have the disease it hit me so hard. I wondered whether I would be able to look after both of them - but I got through it.”
Logan was given six months of chemotherapy and Regan was given four months treatment.
The boys will also have to have a lumbar puncture, where fluid is drained from the spine, every 12 weeks to continue to fight their illness.
The family have been supported by charity Make a Wish Foundation which is paying for the family to go to Disneyland Florida in April 2017.