[1] Univ Manchester, Manchester Med Sch, Manchester M13 9PL, Lancs, England
[2] Univ S Manchester Hosp, Nightingale Breast Ctr, Manchester M20 8LR, Lancs, England
[3] Univ Manchester, Inst Populat Hlth, Manchester M13 9PL, Lancs, England
[4] Univ Manchester, Dept Med Stat, Manchester M13 9PL, Lancs, England
[5] Univ Cambridge, Sch Clin Med, Cambridge CB2 1TN, England