Endorectal endoscopic ultrasound for the locoregional staging of rectal mucosal lesions: retrospective multicenter analysis

Aims Colorectal cancer (CRC) is a common and growing disease and an accurate preoperative staging is essential to choose the most appropriate treatment. There is still debate on the role of transrectal endoscopic ultrasound (TREUS) in locoregional staging. The aim of this study is to establish its role in selecting the most suitable treatment.

Methods A retrospective multicenter study was carried out involving all patients (pts) who underwent TREUS between 2017 and 2022 in the Endoscopy Unit of AOU Città della Salute e della Scienza of Turin and of AOU Maggiore della Carità of Novara for the locoregional staging of mucosal rectal lesions (mRL). Data were collected from an electronic database and expressed as median and interquartile range [IQR] or number and percentage. The primary outcome was to assess the ability of TREUS to differentiate early stages (T0-T1) from advanced stages (T2-T3) which benefit from local excision (endoscopic submucosal dissection ESD or transanal endoscopic microsurgery TEM) and surgical resection, respectively. The diagnostic accuracy of TREUS and magnetic resonance (MR) in the subset of pts that underwent both diagnostic techniques. The surgical pathology stage of resected mRL was the reference standard.

Results 218 pts underwent TREUS in the study time; 122 were excluded: 47 because of other indication than mRL, 3 for inadequate bowel cleansing,16 for advanced adenocarcinoma and severe comorbidity, 24 because of the TREUS was performed after neoadjuvant treatment, 11 because of the time between TREUS and treatment was more than 3 months, 21 for missing data. 96 patients were included, mostly males (63 pz, 65,6%) with a median age of 70,5 years [IQR 61-79,3]; macroscopically mRL were mostly exophytic (58 pz, 60,4%) or flat ( 29pz, 30,3%%), with a median size of 4 cm [IQR 2,7-5] and a median distance from anal verge of 8 cm [IQR 5-10]; 22 pts underwent both TREUS and MR for locoregional staging of mRLs. Regarding treatment, 23 pts (24%) were treated with ESD, 58 pts (60,4%) with TEM, and 15 pts (15,6%) with surgery; 4 pts (4,2%) needed a second treatment since the failure of the first one. The final stage, assessed on surgical pathology was T0 in 71 pts (74,2%), T1 in 15 pts (15,6%), T2 in 5 pts (5,1%), and T3 in pts (5,1%). The overall diagnostic accuracy of TREUS was 89,6%, with 7 mRL (7,3%) over-staged and 3 mRL (3,1%) under-staged. In the subset of pts that underwent both MR and TREUS, the diagnostic accuracy of TREUS in differentiating early from advanced stages was 72,7%, significantly higher compared to MR (45,5%, p value=0.12). [1] [2] [3] [4]

Conclusions TREUS is a reliable staging method for early mRL. The precise evaluation of the rectal wall involvement can be challenging, nonetheless, the clinical impact of TREUS is favorable since it allows to discriminate early stages that benefit from effective and minimally invasive local treatments.

Publication History

Article published online:
15 April 2024

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