A multicentre randomised controlled trial to evaluate the efficacy, morbidity and functional outcome of endoscopic transanal proctectomy versus laparoscopic proctectomy for low-lying rectal cancer (ETAP-GRECCAR 11 TRIAL): rationale and design - Lelong, B; de Chaisemartin, C; Meillat, H; French Research Group of Rectal Cancer Surgery (GRECCAR) (BMC Cancer, 2017)