[1] Haukeland Hosp, Dept Oncol & Med Phys, Bergen, Norway
[2] Univ Bergen, Dept Phys & Technol, Bergen, Norway
[3] Paris Saclay Univ, French Natl Inst Hlth & Med Res, Ctr Res Epidemiol & Populat Hlth, Gustave Roussy,INSERM Unit 1018, Villejuif, France
[4] Univ Copenhagen, Ctr Canc & Organ Dis, Dept Clin Oncol, Copenhagen, Denmark
[5] Univ Copenhagen, Copenhagen, Denmark
[6] MD Anderson Canc Ctr, Dept Radiat Oncol, Houston, TX USA
[7] Univ Toronto, Princess Margaret Canc Ctr, Dept Radiat Oncol, Toronto, ON, Canada
[8] Univ Maryland, Dept Epidemiol & Publ Hlth, Baltimore, MD USA