Indications for and limitations of low anterior resection

The indications for low anterior resection are based mainly on tumor location, penetration depth, histology, macroscopic appearance, etc. Patients with tumors located 2 cm above the puborectal muscle by digital examination can undergo low anterior resection. Distal surgical margins should be at least 1 cm from the tumor in cases of differentiated cancer and localized tumors of stage T2 or less and more than 2 cm in poorly differentiated cancer and tumors of stage T3 or greater with total mesorectal excision (TME). Longer distal surgical margins should be provided in patients with unlocalized tumors and extensive node metastasis. The final decision on whether low anterior resection is appropriate should be made after mesorectal preparation down to the levator muscles with adequate surgical margins. Low anterior resection is contraindicated in patients with poor anorectal function and high age. A rectal stump 1 to 2 cm from the dentate line should be maintained for better postoperative anorectal function if radical excision can still be performed.