International standardization and optimization group for intersphincteric resection (ISOG‐ISR): modified Delphi consensus on anatomy, definition, indication, surgical technique, specimen description and functional outcome

Abstract

AimIntersphincteric resection (ISR) is an oncologically complex operation for very low‐lying rectal cancers. Yet, definition, anatomical description, operative indications and operative approaches to ISR are not standardized. The aim of this study was to standardize the definition of ISR by reaching international consensus from the experts in the field. This standardization will allow meaningful comparison in the literature in the future.MethodA 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.ResultsThree rounds of questionnaire were performed (response rate 100%, 89.6%, 89.6%). Agreement (≥80%) reached standardization on 36 statements.ConclusionThis 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.

A porcine model of laparoscopic intersphincteric resection for ultra- low rectal cancer

“…According to the consensus of international standardization and optimization group for intersphincteric resection (ISOG-ISR), ISR involves a partial, subtotal or total resection of the IAS via intersphincteric dissection [20]. In our model, we executed a complete resection of the IAS, adhering closely to the prescribed surgical access and extent delineated for ISR procedures.…”

Intersphincteric resection following robotic-assisted versus laparoscopy-assisted total mesorectal excision for middle and low rectal cancer: a multicentre propensity score analysis of 1571 patients

“…This definition is confusing and may have resulted in the inclusion of a large proportion of patients with CAA instead of partial ISR. According to the consensus statement from the International Standardization and Optimization Group for intersphincteric resection (ISOG-ISR), partial ISR is defined as a resection at the dentate line 21 . In our study, we clearly distinguished between ISR and CAA to avoid confusion, and we found that RaTME has advantages in both CAA and ISR.…”

Determining the optimal distal resection margin in rectal cancer patients by imaging of large pathological sections: An experimental study

“…[1,2] In nearly 70% of rectal cancer cases, the tumor occurs in the low part of the anal verge, [3,4] and maximizing the protection of the patient's physiological functions while treating the disease is a challenge for surgeons. [5,6] The SL and JW contributed equally to this work.…”