[1] Royal Marsden NHS Fdn Trust, Dept Palliat Med, London SW3 6JJ, England
[2] Royal Brompton NHS Fdn Trust, Dept Palliat Med, London SW3 6JJ, England
[3] Kings Coll London, Cicely Saunders Inst, Dept Palliat Care Policy & Rehabil, London, England
[4] Univ London Imperial Coll Sci Technol & Med, Natl Heart & Lung Inst, London, England
[5] Royal Brompton NHS Fdn Trust, Dept Resp Med, London, England
[6] Kings Coll Hosp London, Dept Resp Med, London, England