Role of magnetic resonance imaging in organ-preserving strategies for the management of patients with rectal cancer

Abstract

Total mesorectal excision has been the most effective treatment strategy adopted to reduce local recurrence rates among patients with rectal cancer. The morbidity associated with this radical surgical procedure led surgeons to challenge the standard therapy particularly when dealing with superficial lesions or good responders after neoadjuvant radiotherapy, to which radical surgery may be considered overtreatment. In this subset of patients, less invasive procedures in an organ-preserving strategy may result in good oncological and functional outcomes. In order to tailor the most appropriate treatment option, accurate baseline staging and reassessment of tumor response are relevant. MRI is the most robust tool for the precise selection of patients that are candidates for organ preservation; therefore, radiologists must be familiar with the criteria used to guide the management of these patients. The purpose of this article is to review the relevant features that radiologists should know in order to provide valuable information during the multidisciplinary discussion and ultimate management decision.

Transanal Local Excision of Rectal Cancer after Neoadjuvant Chemoradiation: Is There a Place for It or Should Be Avoided at All Costs?

“…32 Progressive and significant increases in thickness of these scars should be indicative of possible recurrence. In this setting, baseline MR imaging scans may provide relevant information for comparison during follow-up and are strongly recommended 33 ( Fig. 3 ).…”

Rectal Cancer: Nonoperative Management

“…Magnetic resonance imaging using dedicated rectal cancer protocols provides valuable information about the location of the tumor in relation to other anatomical structures, such as the sphincter complex, the levator muscles, the prostate and seminal vesicles, the vaginal wall and cervix, as well as the anterior peritoneal reflection and helps the surgeon anticipate the need for a permanent stoma, the ability to perform a sphincter-saving procedure and even the type of anastomosis in case proctectomy is undertaken. This information is also very useful for the selection of patients for WW [43]. In summary, patients with lower tumors requiring a low colorectal or a hand-sewn coloanal anastomosis or an APR are more likely to benefit from a WW strategy and organ preservation.…”

“…However, patient discomfort and the difficulties in assessing mesorectal disease away from the rectal lumen contributed to the replacement of ERUS by alternative radiological imaging modalities [57,58]. Magnetic resonance is currently the imaging modality of choice for baseline staging and assessment of response to neoadjuvant therapy in rectal cancer [43]. High-resolution protocols, synoptic reporting, and T2-weighted images are usually sufficient for the assessment of response and identification of patients who are appropriate candidates for a WW program.…”

Nonoperative Management for T2 Low Rectal Cancer: A Western Approach

“…These studies should only be considered for the selection of patients for nCRT after confirmatory biopsies of adenocarcinoma have been obtained and properly documented. 18 The first criterion for this approach is tumor location. Here, the entirety (or at least the central part) of tumors needs to be accessible by the DRE.…”

“…In addition, the risk of achieving a positive ( 1mm pCRM) is quite significant unless primary APE with a definitive stoma is performed. 18 Finally, endoscopic features are definitely relevant for the selection of patients here. The ultimate goal here is to avoid the inclusion of patients with benign lesions or even rectal cancers that fulfill criteria for endoscopic resection through the performance of endoscopic submucosal dissection (ESD).…”