They respond by citing membership-satisfaction polls and insist that those who complain "are beingfrightened by inflammatory language" about rare occurrences, in the words of Susan Pisano, spokeswoman for the American Association of Health Plans.
Mr Nash's family said he had been frightened about being treated at Stafford Hospital after a Healthcare Commission report in 2009 had found "appalling standards" of care there.
Mr Jillings said some of the victims may have deliberately not mentioned well-known people when being questioned because they were frightened of the repercussions.
Other neuroblastoma families being treated at Great Ormond Street have said they are so frightened by the "lottery" they have started raising funds before the child is officially recommended to try the therapy, just in case.