A talented schoolboy died on his way home from a school trip after suffering a "rare complication" from treatment he had for a brain tumour, an inquest has heard.
Billy Belderson, 15, of Woodstone Avenue, Stoneleigh, was discovered unconscious on a coach in Calais on the way back from a skiing trip in Austria, in April this year.
Westminster Coroner’s Court, sitting today, June 18, heard the sociable and well-liked teenager, who was an "exceptional student and won various awards", had been diagnosed with a brain tumour in 2010, for which he had surgery that year.
Coroner Dr Fiona Wilcox said Billy had responded well to treatment, but that the tumour recurred in 2012, after which he had further surgery and radiotherapy and a 'shunt' - a tube - fitted to prevent the build-up of fluid on his brain due to the tumour.
She said that Billy's last scan in January 2013 showed that the tumour had not recurred, but pathologist Dr Michael Heath said that after this point, the shunt had become "completely blocked with cell debris over a period of time" so that when Billy was found on the coach in Calais "there was massive swelling on the brain which affected his vital functions".
Dr Heath said: "The brain was massively enlarged - it was 1820g, when the normal mass is 1350g.
"There was no recurrence of the tumour. As tragic as this is, Billy would not have suffered from a huge headache. He would have gone peacefully into a coma."
Of the blockage, he said: "I have never heard of this. We clearly have to conduct much wider literature research on it to see whether this has been reported."
The court heard how friends sitting with Kingston-born Billy on the coach said he had complained of headache one hour before they reached Calais.
The court heard that when the coach arrived at the port, Billy, a student at The Glyn School, in The Kingsway, Epsom, was found unconscious in his seat and given CPR by qualified staff members until medics arrived 30 minutes later, but that he was pronounced dead shortly afterwards.
Giving her verdict, Coroner Dr Wilcox said: "Billy went to sleep on the coach, sitting next to his brother, resting his head against his brother.
"He just looked asleep and peaceful.
"Billy didn’t die because of his tumour, but because of a complication from the treatment of the tumour.
"Dr Heath acknowledged how rare this complication was.
"Dead cells, perhaps from surgery, perhaps from radiotherapy, had been coming down into the tube.
"The shunt became blocked by cell debris and this led to the cause of death."
Sitting in court, Billy’s parents asked the coroner for further clarification about what happened to Billy and whether it might happen to other people.
Coroner Dr Wilcox said she would write to an expert pathologist to raise concerns about the need for the complication to be investigated "through the appropriate academic channels".
She said: "It’s rare, but if further deaths could be prevented that could be a very good outcome for this court."
Billy raised thousands of pounds for the Royal Marsden Cancer Charity, while battling his tumour, by taking part in a 14-mile walk in 2010, 2011 and 2012 from the Royal Marsden Hospital in Chelsea to the Royal Marsden Hospital in Sutton, where he was treated.