METHOD: A modified Delphi approach with three rounds of questionnaire was adopted. A total of 29 international experts from 11 countries were recruited for this study. Six domains with a total of 37 statements were examined, including anatomical definition; definition of intersphincteric dissection, intersphincteric resection (ISR) and ultra-low anterior resection (uLAR); indication for ISR; surgical technique of ISR; specimen description of ISR; and functional outcome assessment protocol.
RESULTS: Three rounds of questionnaire were performed (response rate 100%, 89.6%, 89.6%). Agreement (≥80%) reached standardization on 36 statements.
CONCLUSION: This study provides an international expert consensus-based definition and standardization of ISR. This is the first study standardizing terminology and definition of deep pelvis/anal canal anatomy from a surgical point of view. Intersphincteric dissection, ISR and uLAR were specifically defined for precise surgical description. Indication for ISR was determined by the rectal tumour's maximal radial infiltration (T stage) below the levator ani. A new surgical definition of T3isp was reached by consensus to define T3 low rectal tumours infiltrating the intersphincteric plane. A practical flowchart for surgical indication for uLAR/ISR/abdominoperineal resection was developed. A standardized ISR surgical technique and functional outcome assessment protocol was defined.
METHODS: This guideline was jointly developed by the Colorectal Cancer Committee of the China Anti-Cancer Association and the International Alliance of NOSES, incorporating recent multicenter data, consensus discussions, and advancements in laparoscopic and robotic techniques. This updated guideline was developed through an expert consensus-based revision process informed by comprehensive literature review and available multicenter clinical evidence, and was finalized after iterative discussion and approval by the guideline steering committee.
RESULTS: This edition provides targeted updates from the previous version, including refined recommendations on preoperative assessment and acknowledgment of robotic assistance. Adjustments to surgical classifications, indications, and procedural descriptions have also been made to enhance clarity and clinical applicability.
CONCLUSION: This updated guideline provides a structured and practical reference for colorectal NOSES procedures, supporting wider adoption and continued surgical advancement.