Assessing surgical difficulty in locally advanced mid–low rectal cancer: the accuracy of two MRI‐based predictive scores

Abstract

Aim Predicting surgical difficulty is a critical factor in the management of locally advanced rectal cancer (LARC). This study evaluates the accuracy and external validity of a recently published morphometric score to predict surgical difficulty and additionally proposes a new score to identify preoperatively LARC patients with a high risk of having a difficult surgery. Methods This is a retrospective study based on the European MRI and Rectal Cancer Surgery (EuMaRCS) database, including patients with mid/low LARC who were treated with neoadjuvant chemoradiation therapy and laparoscopic total mesorectal excision (L‐TME) with primary anastomosis. For all patients, pretreatment and restaging MRI were available. Surgical difficulty was graded as high and low based upon a composite outcome, including operative (e.g. duration of surgery) and postoperative variables (e.g. hospital stay). Score accuracy was assessed by estimating sensitivity, specificity and area under the receiver operating characteristic curve (AROC). Results In a total of 136 LARC patients, 17 (12.5%) were graded as high surgical difficulty. The previously published score (calculated on body mass index, intertuberous distance, mesorectal fat area, type of anastomosis) showed low predictive value (sensitivity 11.8%; specificity 92.4%; AROC 0.612). The new EuMaRCS score was developed using the following significant predictors of surgical difficulty: body mass index > 30, interspinous distance < 96.4 mm, ymrT stage ≥ T3b and male sex. It demonstrated high accuracy (AROC 0.802). Conclusion The EuMaRCS score was found to be more sensitive and specific than the previous score in predicting surgical difficulty in LARC patients who are candidates for L‐TME. However, this score has yet to be externally validated.

Mesorectal fat area and mesorectal area affect the surgical difficulty of robotic‐assisted mesorectal excision and intersphincteric resection respectively in different ways

“…Yamaoka et al . reported that MFA was an independent predictor of surgical difficulty in robotic‐assisted TME [17], while the study from EuMaRCS did not show any influence of MFA on the difficulty of laparoscopic TME [16]. Escal et al .…”

“…Pathological T stage was associated with robotic-assisted ME, following the results of laparoscopic surgery for rectal cancer [12]. The pathological T stage was one of the important factors in the European MRI and Rectal Cancer Surgery (EuMaRCS) scoring system [16]. However, for juxta-anal rectal cancer, the pT stage was not a predictor of difficulty for robotic-assisted ISR.…”

“…Various studies have reported on the factors affecting the difficulty of TME surgery, such as body mass index (BMI), visceral fat area, mesorectal fat area (MFA) and other pelvimetric parameters [12][13][14]. Several grading systems of surgical difficulty were established to evaluate the influence on operative time, blood loss and surgical quality of laparoscopic surgery for rectal cancer [14][15][16]. Due to the rigid instruments and limited degrees of freedom, laparoscopic surgery is technically challenging for low rectal cancer in a deep narrow pelvis.…”

3D pelvimetry and biometric measurements: a surgical perspective for colorectal resections

“…If this applies for a proctoscope, it would be consistent to find a difference also when a flexible or rigid trans-anal platform is placed and used in procedures where dissection is based on geometrical tips (the so-called O and triangle dissection planes) [5] and on a dynamic anatomic distortion made by the pneumorectum [5]. Several authors correlated the anatomical variables with surgical results, for open, robotics, laparoscopic, and TaTME dissections [8,[17][18][19][20][21][22][23][24]. In a small series of patients who underwent open surgery for low rectal tumours, no significant differences were detected between the pelvis depth of females and males.…”

Indocyanine green fluorescence‐guided robotic total mesorectal excision with handsewn coloanal anastomosis for rectal cancer — a video vignette

“…At the restaging MRI, the lesion showed a moderate response (ymrT2N0). After estimating the European MRI and Rectal Cancer Surgery (EuMaRCS) score for surgical difficulty (2/10) [3], an ‘up‐to‐down’ rectal resection was planned.…”