Earlier this year Leslie Burke, from the Newton estate, went to the High Court to challenge guidance from the General Medical Council (GMC) on withholding life-prolonging treatment.
He feared that as his condition worsens doctors could decide his quality of life is so poor that they withdraw artificial nutrition.
The High Court ruled in his favour, arguing that if a patient has made a living will or expressed that they would want life-prolonging treatment, doctors must fulfil that wish.
Unclear
The GMC has now appealed against some aspects of the judgement arguing that 'key issues' remain unclear.
Ruth Evans, chair of the GMC standards and ethics committee, said: "The question whether a life-prolonging treatment should be started, or should be withdrawn, is painful for patients, their family and the doctors to address.
"Some patients will want everything possible to be done, while others will want to avoid too much medical intervention, when they are nearing the end of life.
"Doctors want clear guidance to help ensure individual patients receive the care that's right for them.
"This is why we are appealing the judgement."