Radiotherapy dose escalation using endorectal brachytherapy in elderly and frail patients with rectal cancer unsuitable for surgery: Lessons from studies in fit patients and future perspectives

•Incidence of rectal cancer increases in elderly with aging population.•The optimal management of elderly frail patients with rectal cancer remains unclear.•Radiotherapy dose escalation with rectal brachytherapy offer an attractive option.•Prospective studies testing this strategy for organ preservation are warranted.•Multidisciplinary work and shared decision making should be prioritized.