Megrahi has been diagnosed with "advanced stage" cancer
Lockerbie bomber Abdelbaset al-Megrahi is battling "advanced stage" cancer, his lawyer has said.
The 56-year-old former Libyan intelligence agent has been diagnosed with prostate cancer after hospital tests last month.
Solicitor Tony Kelly said the disease had spread to other parts of his body.
Megrahi is serving a life sentence with a minimum term of 27 years for the bombing of Pan Am flight 103 in 1988, which led to the deaths of 270 people.
Last week Megrahi won the latest round of his long-running legal battle to overturn his conviction.
He has already lost an appeal against his 2001 conviction but the Scottish Criminal Cases Review Commission (SCCRC) ordered another.
List of objections
In a 790-page report, the commission highlighted five reasons which led it to believe that Megrahi's conviction might be a miscarriage of justice.
Appeal court judges rejected arguments from the Crown that only the concerns voiced by the commission should be considered when he appears before them.
Megrahi's legal team asked for its own grounds of appeal to be added and submitted its list, running to 317 pages.
No date has yet been fixed for a hearing which will finally decide whether the guilty verdict should stand.
Megrahi's lawyer said: "Following hospital tests, Mr Megrahi was last month diagnosed with prostate cancer.
"Unfortunately the disease has spread to other parts of his body and is therefore at an advanced stage.
"Mr Megrahi asks that the privacy of his family is respected at this difficult time."
Mr Kelly added: "He wishes me to make clear that the fight to overturn his wrongful conviction for the Lockerbie bombing will go on.
"We on his legal team are continuing to prepare his appeal, which we hope will take place some time next year."
Dr Jim Swire, whose daughter Flora died in the bombing, called for Megrahi's appeal to be speeded up.
He said: "I feel that it is a very serious threat to his life and it would be a tragedy if he is to spend the rest of his life in a Scottish prison, particularly if he is not guilty of the crime of which he was found guilty.
"I'm not satisfied that the verdict against him is correct.
"It sounds to me like an unfolding human tragedy."
Dr Swire, who is also spokesman for the UK Families Flight 103 group, added: "If his prognosis is bad then I hope that the Scottish authorities would look for a way of speeding up the next appeal without compromising the fairness of it.
"It would be an act of great humanity to do that."