Kian Jones, 12, of Racecourse Avenue, Shrewsbury, needed an emergency operation at Birmingham Children's Hospital after a 2.5cm cancerous tumour was discovered in his brain in October.
His parents Dave and Sabina said today they were told by medical staff in Birmingham that if his condition had not been discovered when it was, Kian could have died within a week.
Health bosses at the Royal Shrewsbury Hospital have refused to comment on Kian's case but they said they had invited the family to meet with the Trust to discuss their concerns.
The Belvidere School pupil had begun vomiting, suffering serious headaches and having problems with his vision in late August, with his parents taking him to the RSH on three occasions before a CT scan was carried out and identified the tumour.
When he was first admitted to hospital on September 1, Mrs Jones said they were told by doctors Kian may have been suffering some form of gastroenteritis.
Mrs Jones said: "I was on the computer Googling and looking up symptoms of persistent headaches and vomiting and the site said your GP would normally refer you for a CT scan to rule out anything serious."