['Transanal endoscopic microsurgery (TEM) is a minimally invasive technique for the excision of rectal lesions, with lower morbidity and mortality rates than open surgery. Following advances in laparoscopic colorectal surgery and endoscopic mucosal resection, this study evaluated the safety and efficacy of TEM in the treatment of complex rectal lesions.', 'All patients were entered into a prospective database. Complex lesions were identified as high (more than 15 cm from anorectal margin), large (maximum dimension over 8 cm), involving two or more rectal quadrants, or recurrent.', 'Seventy-one lesions (13 carcinomas and 58 tubulovillous adenomas) were identified. The median duration of operation was 60 (interquartile range (i.q.r.) 30-80) min, with an estimated median blood loss of 0 (i.q.r. 0-10) ml. Median hospital stay was 2 (i.q.r. 1-3) days. One patient developed postoperative urinary retention and one returned with rectal bleeding that did not require further surgery. Two patients developed rectal strictures after operation that were dilated successfully. There was no recurrence of benign lesions during a median follow-up of 21 (i.q.r. 6.5-35) months.'] Is transanal endoscopic microsurgery a safe and reliable technique even for complex rectal lesions?