 In 1992 Cox noticed that he had breathing difficulties and it was discovered that he had an unusual tumour in his left nostril.This was treated, but during his five-year check up, a further tumour was noted on his pituitary gland In April 2004, he began to lose his sight as a result of a rare vascular cancer, haemangiopericytoma.In preparation for surgery he was prescribed the steroidal drug, dexamethasone, one of the effects of which was to initiate a temporary burst of mental and physical energy.