The family of a young boy who may only have days or weeks to live are pinning their hopes on pioneering trials in America.

Jack Howard, from Hartley, is battling kidney cancer for the second time in his 12 short years.

The Gravesend Grammar School pupil is desperately ill. A tumour protruding from his side is growing by 20% every week and after months of treatment, NHS doctors have said there is nothing more they can do for him.

Parents Nick and Zoe Howard, both 42, were distraught and have had to watch their eldest son grow weaker by the day. He has now lost more than a third of his body weight.

Mr Howard, a Thames oil tanker skipper, said: “The NHS has done absolutely everything they can for Jack but the cancer is not responding to conventional treatments. Now they are out of options.”

Jack, who is a huge West Ham United fan, was first diagnosed with cancer in 2012 when he suddenly began wetting his bed. Although his original GP dismissed the problem as nothing serious, a new doctor found a lump in his abdomen on their fourth visit.

By then the tumour had grown so large it had spread to one of his lungs. Following an intense course of chemotherapy, radiotherapy and surgery to remove his left kidney, he was on his way to recovery.

Mr Howard said: “We were told that if he was clear for two years than we would be out of the danger zone for a relapse.

“When it came back at 23 months, we were devastated.”

Because Jack had already gone through radiotherapy during the first bout of treatment when they discovered the relapse in January this year, he was unable to have it again.

Mrs Howard, who is a teacher at Our Lady of Hartley Primary School, said: “I am heartbroken to see my beautiful boy go through such suffering and pain for a second time. All Jack wants is to have a normal life like any other child - he longs to go back to school and wants to be a doctor when he is older. I pray this will come true. I love him so much it hurts.”

His aunt, Keely Howard added: “He screams out in pain, it’s horrendous. We’re such a close family and we can’t lose Jack, we just can’t.”

The family, which also includes Jack’s brother Callum, who is 11 and eight-year-old Lucy, are now hoping that treatment in America could be the answer.

Other children with Neuroblastoma, another form of childhood cancer, and some others from the Royal Marsden Hospital where Jack is being treated have already gone out there for the trial and are having some success.

But it comes at a price.

Mr Howard added: “I’ve never asked for anything in my life and we don’t know how much it will cost. But if we have to we will sell the house to get treatment.”

The family have been advised it could be in the region of £250,000, subject to an initial examination, and a £75,000 deposit is also required.

Keely has set up a crowd funding page to help the family and said: “We want to be ready to go straight away, there is no time to lose, every day, every week counts against us.”

Mr Howard added: “As parents we have to keep it together for the sake of Jack and other two children. This is a terrible time but we have to put a brave face on it and stay strong.”

To help visit the crowdfunder page here.