A review of clinical impact of endoscopic ultrasound staging in rectal cancer
,1,* Zeynab yaberi mohammad
1. Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
2. Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Endoscopic ultrasound (eus) is a highly useful technique for local staging of rectal cancer, as preoperative staging determines the type of surgery performed and whether preoperative neoadjuvant chemoradiation is needed. eus may alter patient management in relation to surgical candidacy, extent of resection, and/or radiation therapy field.
Publications were retrieved by a systematic search of multiple bibliographic databases, including medline, embase, scopus, cochrane library, web of science, biomed central, science direct, and google scholar. the language of search was restricted to english.
Savides et al, summarized the indications for eus in rectal cancer after a review of the literature and of potential impact, based on t stage. indications for eus in rectal cancer include: (i) determination suitability for endoscopic mucosal resection or trans anal excision (if the lesion is t1 by eus) in a large polyp or small rectal cancer; (ii) determination of whether preoperative chemotherapy and radiation is required in a large rectal cancer (t2: radical resection; t3–4 or n1: preoperative chemoradiation followed by radical resection); (iii) surveillance after surgery for rectal cancer. harewood et al. have published multiple studies on the clinical impact of eus in rectal cancer. they concluded that preoperative staging with eus results in more frequent use of preoperative neoadjuvant therapy than if staging was performed with ct alone. an evidence-based consensus statement on the role and application of endosongraphy for rectal cancer staging in clinical practice was published in 2008, as previously discussed. most rectal cancers present at an advanced-stage t3 and/or n1 stage (75%). accurate assessment of these groups is important for those patients eligible for preoperative chemotherapy and radiation protocols. eus can assess the crm for anteriorly located tumors by assessing the extent of tumor involvement of the mesorectal fascia. the distance from the tumor to the crm is an important predictor for recurrence of rectal cancer after surgery. the relation of tumor edge to the circumferential margin is an important factor in deciding the need for neodjuvant treatment and prognosis. sphincter-saving trans anal excision of an early (t1n0) lesion can be performed instead of an abdominoperineal resection, which can be reserved for more advanced lesions that have penetrated into the muscularis propria or beyond. however, determination of malignancy within a large adenoma at the level of the anal sphincters may be technically very difficult, due to artifacts. in another study, on clinical impact in rectal cancer, eus staging information changed the surgeon’s original treatment plan based on ct alone in 31% of patients.
The role of eus staging in colon cancers throughout the rest of the colon is less clear, as these patients would undergo laparotomy and resection anyway, if there were no distant metastases. however, eus may be a helpful staging modality for proximal colon cancers, with the advent of minimally invasive laparoscopic and endoscopic mucosal resection for early lesions, and also if neoadjuvant chemotherapy of locally advanced proximal colon cancers becomes more common.
Endoscopic ultrasound, staging, rectal cancer.