“…Seven studies took place in the USA [49,50,55,56,59,60], two in Canada [47,51] and one each in China [52], Japan [54], Korea [57], Sweden [58] and UK [48]. Five studies recruited patients with prostate cancer only [47,48,55,57,60], one each recruited bladder [58], lung [52] and breast cancer only [51], with the remaining recruiting a mixed sample of cancer types [49,50,53,54,56,59].…”