The American Society of Colon and Rectal Surgeons (ASCRS) is dedicated to ensuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Clinical Practice Guidelines Committee is composed of society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus and to develop clinical practice guidelines based on the best available evidence. Although they are not proscriptive, these guidelines provide information on which decisions can be made and do not dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. These guidelines should not be deemed inclusive of all proper methods of care nor exclusive of methods of care reasonably directed toward obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all the circumstances presented by the individual patient. STATEMENT OF THE PROBLEM Colorectal cancer remains the third most common cancer for both men and women, and the second leading cause of cancer-related deaths in the United States annually. It is projected that 145,600 new colorectal cancer cases will have been diagnosed and an estimated 51,020 deaths from colorectal cancer will have occurred in 2019.1 It is difficult to estimate statistics attributable specifically to rectal cancer because, historically, much of the reporting for rectal cancer has been combined with colon cancer as the single disease entity of “colorectal cancer.”1 Overall, the incidence of colorectal cancer has declined over the past decades, largely because of risk factor modification and screening.2 However, the 18- to 50-year age group represents a unique cohort of patients in whom the incidence of rectal cancer has been increasing. In contrast to overall trends, rectal cancer incidence increased by 1.8% annually in younger adults between 1990 and 2013.1 In an effort to ensure that patients with rectal cancer receive appropriate care using a multidisciplinary approach, the ASCRS collaborated with a multispecialty effort to develop the National Accreditation Program in Rectal Cancer to create educational modules and a set of clinical standards focusing on program management, clinical services, and quality improvement regarding rectal cancer.3,4 Because rectal cancer management involves multiple disciplines working in conjunction with one another, the surgical guidelines presented here must be viewed within that context and represent only a portion of the treatment necessary for the optimal care of patients with rectal cancer. Colorectal cancer screening, bowel preparation, enhanced recovery pathways, surveillance after curative treatment, and prevention of thromboembolic disease, while relevant to the management of patients with rectal cancer, are beyond of the scope of these guidelines and are addressed in other guidelines.5–9 A guideline focusing on colorectal surgery and frailty is forthcoming. METHODOLOGY These guidelines are based on the last set of ASCRS Practice Parameters for the Management of Rectal Cancer published in 2013.10 A systematic search of MEDLINE, PubMed, Embase, and the Cochrane Database of Collected Reviews was performed from January 1, 2013 through January 15, 2020. Individual literature searches were conducted for each of the different sections of the guideline (Fig. 1). An additional limitation to core clinical journals was applied if the initial word combination search returned more than 500 articles. Directed searches using embedded references from primary articles were performed in selected circumstances. The 1812 screened articles were evaluated for their level of evidence, favoring clinical trials, meta-analysis/systematic reviews, comparative studies, and large registry retrospective studies over single institutional series, retrospective reviews, and peer-reviewed, observational studies. Additional references identified through embedded references and other sources as well as practice guidelines or consensus statements from relevant societies were also reviewed. A final list of 361 sources was evaluated for methodologic quality, the evidence base was examined, and a treatment guideline was formulated by the subcommittee for this guideline. The final grade of recommendation and level of evidence for each statement were determined using the Grades of Recommendation, Assessment, Development, and Evaluation system (Table 1). When agreement was incomplete regarding the evidence base or treatment guideline, consensus from the committee chair, vice chair, and 2 assigned reviewers determined the outcome. Members of the ASCRS Clinical Practice Guidelines Committee worked in joint production of these guidelines from inception to final publication. Recommendations formulated by the subcommittee were reviewed by the entire Clinical Practice Guidelines Committee. Final recommendations were approved by the ASCRS Executive Council. In general, each ASCRS Clinical Practice Guideline is updated every 5 years. No funding was received for preparing this guideline, and the authors have declared no competing interests related this material. This guideline conforms to the Appraisal of Guidelines for Research and Evaluation (AGREE) checklist.TABLE 1.: The GRADE system: grading recommendationsFIGURE 1.: PRISMA literature search flow sheet. CPG = Clinical Practice Guideline.Defining the Rectum The lower limit of the rectum is usually defined by the anorectal ring, an anatomic landmark palpable on physical examination or visible radiographically as the upper border of the anal sphincter and puborectalis muscles.11 The upper limit of the rectum has been variably defined by the splaying of the teniae coli, the sacral promontory, the proximal valve of Houston, or the level of the peritoneal reflection. A recent consensus conference defined the point of the sigmoid take-off (ie, the junction of the sigmoid mesocolon and mesorectum) as seen on cross-sectional imaging as the upper limit of the rectum.12 Given that the correlation among these landmarks is imperfect and the presence of all 3 valves of Houston is inconsistent, the upper limit of the rectum, from a clinical perspective, can be somewhat elusive. In practice, the location of a rectal cancer is most commonly assessed by the distance from its distal margin to the anal verge, defined as the beginning of the hair-bearing skin. Tumors within 15 cm of the anal verge are typically classified as rectal cancers, although the total length of the rectum can vary by body habitus and sex.11 PREOPERATIVE ASSESSMENT Evaluation 1. A cancer-specific history should be obtained eliciting disease-specific symptoms, associated symptoms, family history, and perioperative medical risk. Routine laboratory values, including CEA level, should also be evaluated, as indicated. Grade of recommendation: Strong recommendation based on moderate-quality evidence, 1B. A cancer-specific history remains a cornerstone of the preoperative evaluation. Bleeding, pain, or symptoms related to obstruction should be assessed to help determine the urgency and sequence of evaluation and intervention; this consideration is particularly relevant when neoadjuvant therapy is being considered. Urinary, sexual, and bowel function should be reviewed and symptoms indicative of malignant fistulas or severe radiating pain may alert the surgeon to locally advanced disease involving adjacent pelvic organs. The patient’s medical fitness to undergo multimodality treatment should be assessed to guide treatment planning and perioperative management. A thorough discussion of perioperative risk stratification is beyond the scope of this guideline.13–15 A family history should typically document relevant premalignant lesions and cancers including details like the age at diagnosis and the lineage of affected first- and second-degree relatives. Patients should be asked about known predisposing hereditary cancer syndromes, prior genetic testing, and family ancestry or ethnicity that may be relevant.16 Patients with findings suggestive of an inherited susceptibility to colorectal cancer should typically be referred for genetic counseling. Guidelines on the management of patients with inherited colorectal cancer have been previously published.17,18 Routine laboratory bloodwork and a CEA level are part of the preoperative evaluation. The baseline CEA level before initiating elective treatment is prognostic of long-term survival and is used as a reference during posttherapy surveillance.19 Although CEA levels assessed at different time points during multimodality treatment can correlate with treatment response, CEA does not reliably predict pathologic response to neoadjuvant therapy.20–23 There is insufficient evidence to support the routine use of other tumor markers such as CA19-9 in the evaluation of patients with rectal cancer.24 2. As a part of a complete physical examination, the distance of the distal extent of the cancer from the anal verge and the cancer’s relation to the sphincter complex should typically be assessed. Grade of recommendation: Strong recommendation based on low-quality evidence, 1C. Assessment of the relationship between the distal extent of the lesion to both the anorectal ring (ie, top of the sphincter complex) as well as the anal verge is essential for treatment planning and for evaluating the patient’s candidacy for sphincter preservation and should ideally be performed before initiating neoadjuvant therapy, which may cause regression of the lesion. The distance should be assessed by digital examination and endoscopically (rigid proctoscopy may provide a more accurate measurement than flexible sigmoidoscopy). Endoscopic tattooing for purposes of anticipated intraoperative localization or to facilitate mucosal surveillance in the event of a clinical complete response may be helpful.25–29 3. Before elective treatment, the histological diagnosis of invasive adenocarcinoma should be confirmed, and patients should typically undergo a full colonic evaluation so the treatment plan can address synchronous pathology, as needed. Grade of recommendation: Strong recommendation based on moderate-quality evidence, 1B. It is important to confirm the histological diagnosis of invasive adenocarcinoma before initiating therapy in the elective setting, because rectal neoplasms of other histologies may be amenable to nonresectional or different multimodality treatment options.30 Because endoscopic biopsy may be nondiagnostic or incongruent with the clinical impression of invasive adenocarcinoma because of a sampling error, repeat endoscopic or operative biopsies may be required to establish the histological diagnosis for purposes of treatment planning. Operative excisional biopsy is typically not performed unless it is done as a curative-intent transanal full-thickness excision with adequate radial margins as discussed in detail later. Patients newly diagnosed with rectal cancer should typically undergo a full colon evaluation. Although the incidence of synchronous colorectal cancer is low, in the range of 1% to 3%, the incidence of synchronous adenomas or other polyps can be as high as 30%.31–34 Colonoscopy is a preferred evaluation method because it offers a therapeutic platform to treat synchronous polyps.35,36 In cases where a colonoscopy is not completed, for instance, due to an obstructing cancer, CT colonography may be used.37–40 Computed tomography colonography has been shown to be a superior diagnostic study compared with double-contrast barium enema among patients with symptoms suggestive of colorectal cancer and can detect synchronous lesions.41 In patients receiving neoadjuvant therapy, colonoscopy may be reattempted if there is sufficient tumor regression to permit passage of a colonoscope. If a preoperative colon evaluation is not performed, typically in cases where urgent intervention is needed for obstructing lesions, a complete colonoscopy should be planned postoperatively. Staging 1. Rectal cancer should typically be staged according to the American Joint Committee on Cancer TNM system before initiating treatment. Grade of recommendation: Strong recommendation based on moderate-quality evidence, 1B. Rectal cancer should be staged according to the TNM system before treatment, except when emergent surgery is required. The TNM system, as defined by the American Joint Committee on Cancer, describes the depth of local tumor invasion (T stage), the extent of regional lymph node involvement (N stage), and the presence of distant metastasis (M stage).42,43 Updated 8th edition staging definitions categorize lymph nodes harboring micrometastasis (clusters of 20 or more cancer cells or metastases measuring >0.2 mm and <2 mm in diameter) as N1 disease, the presence of tumor deposits (N1c disease) as stage III regardless of the status of the lymph nodes, and peritoneal metastases as M1c disease.42,43 Rectal cancer should be described by both its initial clinical stage (cTNM), which guides treatment decisions, as well as the final pathologic stage (pTNM), which can provide prognostic information.42 Clinical stage can be further prefixed to designate the staging modality used, including u for ultrasound, mr for MRI, and ct for CT scan. For patients treated with preoperative therapy, pathologic tumor response is reported as ypTNM.44,45 2. Rectal cancer protocol pelvic MRI is the preferred modality for locoregional clinical staging. Endorectal ultrasound (EUS) may be considered when differentiating between early T stages (ie, T1 versus T2 tumors) or when MRI is contraindicated. Grade of recommendation: Strong recommendation based on moderate-quality evidence, 1B. Magnetic resonance imaging staging of rectal cancer, using standardized technical protocols and reporting templates, assesses the depth of tumor penetration, presence of locoregional nodal metastases, and the relationship between lesions (tumor and/or nodes) within the mesorectum and the mesorectal fascia.46,47 Thus, MRI can help predict surgical clearance of the circumferential resection margin (CRM), the shortest distance between disease (tumor and/or malignant nodes) and the mesorectal fascia.47–49 A positive CRM has been variably defined as cancer within 1 mm or within 2 mm50,51 of the mesorectal fascia or levator ani muscle; the National Comprehensive Cancer Network currently defines it as within 1 mm.52 A positive CRM is associated with increased risk for local recurrence and decreased survival (5-year local recurrence: HR = 3.50; 95% CI, 1.53–8.00; p < 0.05; 5-year overall survival: HR = 1.97; 95% CI, 1.27–3.04; p < 0.01).53–55 Primary tumor features including T4 status, extramural vascular invasion, CRM within 1 mm, or extramural tumor depth of at least 5 mm are considered high-risk features.56,57 These factors should be considered as a critical part of clinical staging and are vital for planning preoperative therapy as discussed in Multidisciplinary Treatment Planning. Endorectal ultrasound should typically be considered complementary to MRI for purposes of clinical staging and is most useful in differentiating between early T stages (ie, T1 versus T2 tumors).57 Magnetic resonance imaging may also be contraindicated when certain implantable medical devices are present (ie, metallic implants, MR incompatible pacemakers).58,59 Disadvantages of EUS include operator dependency, limited accuracy in assessing bulky or locally advanced lesions, patient discomfort, and inability to evaluate stenotic lesions that preclude passage of the transducer.58,59 Accurately staging potentially involved pelvic lymph nodes (including mesorectal, lateral pelvic, and inguinal compartments) remains a diagnostic challenge for all imaging modalities.60 Sensitivity and specificity for clinical nodal staging have been reported as 55% and 74% for CT, 67% and 78% for EUS, and 66% and 76% for MRI.48,61 Nodal staging accuracy may be improved by incorporating criteria such as a spiculated border and mixed signal intensity as seen on MRI.57,62,63 3. Clinical staging for metastatic disease should typically be conducted in patients with rectal cancer. Grade of recommendation: Strong recommendation based on moderate-quality evidence, 1B. Clinical staging of distant metastatic disease should typically be completed before initiating treatment, because the presence of metastatic disease influences the treatment plan. In patients with metastatic rectal cancer from the Swedish Cancer Registry, the most common sites of metastasis were liver (70%), lung (47%), bone (12%), and nervous system (8%).64 Clinical staging should typically include contrast-enhanced CT scan of the chest, abdomen, and pelvis. Pulmonary CT, with its increased sensitivity and better ability to arbitrate otherwise indeterminate lesions over time, is recommended rather than chest x-ray.65,66 Computed tomography without intravenous contrast followed by triphasic (arterial, venous, and portal) contrast is generally the modality of choice for detecting and characterizing hepatic lesions.67–69 For smaller lesions, and to evaluate a liver with background fatty liver changes, MRI may be superior to multidetector CT and positron emission tomography (PET). There is insufficient evidence to support the routine use of PET/CT alone in the clinical staging of primary rectal cancer.60 Although PET/CT has been used for staging patients with suspected disease recurrence or for excluding other sites of distant disease in patients with stage IV rectal cancer being considered for curative-intent surgery, the evidence supporting added clinical value is limited.70,71 Positron emission tomography /CT may have a role in evaluating equivocal findings on contrast-enhanced CT.72,73 4. Restaging evaluation should be considered after neoadjuvant therapy in patients with locally advanced rectal cancer. Grade of recommendation: Strong recommendation based on low-quality evidence, 1C. Restaging evaluation consisting of clinical and endoscopic assessment and cross-sectional imaging should typically be considered after neoadjuvant therapy, in particular, if the assessment of local tumor response would influence the need for additional therapy and/or alter the surgical approach, or if there is a unique concern for interval development of metastatic disease. Importantly, restaging evaluates patients for a possible clinical complete response (cCR) and can adjust patient expectations. Some studies have demonstrated a change in treatment strategy after restaging in 11% to 15% of patients, typically due to identification of metastatic disease, but others have shown limited or no benefit to restaging.74,75 Although restaging is typically performed by repeating the same imaging studies that were done initially, the assessment of tumor response to neoadjuvant therapy has been challenging because of limited T and N staging accuracy for MRI, CT, or EUS in this setting.76–79 Advanced functional MRI (ie, diffusion-weighted MRI) and/or PET/CT scan may potentially improve the accuracy of assessing treatment response.70,80 Multidisciplinary Treatment Planning 1. The treatment of patients with rectal cancer should typically incorporate a multidisciplinary team tumor board discussion. Grade of recommendation: Strong recommendation based on low-quality evidence, 1C. Optimal management of patients with rectal cancer requires input and coordination among a team of clinicians including expertise from surgery, pathology, radiology, radiation, and medical oncology, and other ancillary team members. Although discussion of rectal cancer management by an multidisciplinary team can improve preoperative clinical staging, modify and individualize multimodality treatment, plan technical aspects of surgery, and review pathologic staging, more studies are needed to demonstrate a potential impact on disease-free and overall survival (OS).81–83 2. If either a temporary or permanent ostomy is being considered, preoperative education and stoma site marking should typically be performed. Grade of recommendation: Strong recommendation based on moderate-quality evidence, 1B. Consultation with an enterostomal therapist is typically recommended for patients whose rectal cancer treatment may involve stoma creation. Preoperative stoma site marking and patient education can improve time to ostomy proficiency and decrease ostomy-related complications.84–86 Guidelines on stoma marking and surgery have been previously published.87,88 TREATMENT Surgical Techniques and Operative Considerations Local Excision 1. Local excision is an appropriate treatment modality for carefully selected patients with cT1N0 rectal cancer without high-risk features. Grade of recommendation: Strong recommendation based on moderate-quality evidence, 1B. Local excision is an acceptable curative-intent treatment in highly selected patients with cT1N0 rectal cancer with favorable clinical and histological features. Transanal excision may also be appropriate for patients with more advanced cT disease but who are considered medically unfit for radical cancer surgery. Whereas local excision offers advantages of minimizing operative risk and functional sequelae, it does not adequately remove or pathologically stage the mesorectal lymph nodes. The risk of occult nodal metastasis from T1 lesions ranges from 6% to 11% with greater risk associated with pathologic features such as SM3 invasion, poor differentiation, tumor budding, and lymphovascular or perineural invasion.89,90 Accurate preoperative staging and careful patient selection are essential when contemplating local excision. Distinguishing early depth of invasion (ie, Tis, T1, T2) may be difficult with MRI, and EUS may be utilized as a complementary staging tool in certain situations. Clinical criteria for local excision typically include small (<3 cm) adenocarcinomas limited to <30% of the rectal circumference, that are well or moderately differentiated, without lymphovascular invasion, perineural invasion, tumor budding on tissue biopsy, and no clinical nodal involvement, and that are accessible transanally for full-thickness excision.52 Given our current understanding of the applicability of local excision, the grade of this statement has been changed from a 2B in the 2013 guidelines to a 1B.10 Technically, local excision involves full-thickness excision, ideally with a ≥10 mm grossly normal circumferential margin with a depth down to perirectal fat providing a minimum of a 2-mm-deep margin.52 The surgeon should typically orient the specimen to facilitate pathologic assessment, and tangential, piecemeal, or fragmented excision should be avoided, if possible. The procedure can be performed as a conventional transanal excision or by using a transanal endoscopic platform like transanal endoscopic microsurgery (TEMS) or transanal minimally invasive surgery (TAMIS). While there is a paucity of well-designed randomized, controlled trials, studies suggest that TEMS offers better visualization and access to more proximal lesions than conventional transanal excision, and TEMS and TAMIS appear to be comparable.91–93 Endoscopic submucosal dissection, an advanced colonoscopic procedure, can potentially treat lesions with very superficial submucosal invasion, but the optimal patient selection criteria for this approach remain controversial.94 The rate of local recurrence following local excision varies from 7% to 21% for T1 lesions and is consistently higher than that after radical resection.95–97 Patients should appreciate that if pathologic examination reveals significant risk factors like deeper T stage, inadequate margins, poor differentiation, deep submucosal (SM3) invasion, tumor budding, or lymphovascular or perineural invasion, subsequent radical resection will typically be recommended. In general, local excision is considered an oncologically inadequate treatment for cT2 lesions because the local recurrence rate ranges from 26% to 47%, and these tumors have an elevated risk for harboring occult nodal disease.98 Radical resection should typically be recommended under these circumstances. When patients with high-risk T1 and T2 lesions refuse radical resection or prioritize sphincter preservation, adjuvant chemoradiation in combination with local excision has been considered. In a systematic review of patients with pT1/T2 rectal lesions removed by local excision, those who went on to receive adjuvant chemoradiation (n = 405) were compared to those who underwent radical resection (n = 130). Despite the limited retrospective data and selection bias, the weighted average local recurrence rates for adjuvant chemoradiation and radical resection were 10% (95% CI, 4–21) versus 6% (95% CI, 3–15) for pT1 lesions and 15% (95% CI, 11–21) versus 10% (95% CI, 4–22) for pT2 lesions.99 Thus, in high-risk patients who refuse or are unfit for radical resection, adjuvant chemoradiation should typically be recommended after local excision and should be followed by surveillance for a potentially salvageable recurrence.100 Local excision has also been performed after neoadjuvant chemoradiation for select T1/T2 lesions. This approach has been studied in clinical trials.101–104 Two prospective trials randomly assigned 50104 and 47103 patients with cT2 rectal cancer to neoadjuvant chemoradiation and local excision versus standard resection. Long-term data reported no statistically significant differences in local recurrence or disease-free survival. However, a pooled analysis demonstrated high rates of morbidity (22.3%), in particular, postoperative pain and suture line dehiscence (9.7% for each).105,106 These patients require counseling regarding possible long-term outcomes, and the safety and efficacy of this approach remain unestablished in routine clinical practice. Radical Resection 1. A thorough surgical exploration should typically be performed at the time of operation. Grade of recommendation: Strong recommendation based on low-quality evidence, 1C. Surgical exploration should typically include a thorough assessment of the peritoneal cavity and the abdominal organs to detect or rule out metastatic disease (eg, radiographically occult metastasis, carcinomatosis), more advanced local disease (eg, fixation to adjacent organs), synchronous lesions, or coexisting pathology.107 Unexpected findings that impact the operative plan and the decision to proceed with the operation should, ideally, be discovered before ligating the vascular pedicle and committing to a resection. 2. For curative resection of tumors of the upper third of the rectum, a tumor-specific mesorectal excision should typically be performed as part of a low anterior resection (LAR) with the mesorectum divided, ideally, at least 5 cm below the distal margin of the tumor. For tumors of the middle and lower thirds of the rectum, total mesorectal excision (TME) should typically be performed as a part of an ultralow anterior resection or abdominoperineal resection (APR). A 2-cm distal mural margin is usually adequate for distal rectal cancers when combined with TME. A 1-cm distal mural margin is generally acceptable for cancers located at or below the mesorectal margin. Grade of recommendation: Strong recommendation based on the high-quality evidence, 1A. Appropriate surgical technique is integral to optimizing oncological outcomes and minimizing morbidity, and should follow the principles and anatomic planes of a TME. Dissection between the visceral and parietal layers of the endopelvic fascia facilitates en bloc removal of the rectal cancer and associated mesentery, lymphatics, and tumor deposits. Mesorectal excision can preserve the autonomic nerves and reduce intraoperative bleeding and the rate of local recurrence.108 Among patients registered in Medical Research Council (MRC) CR07 and NCIC-CTG CO16 trial, the 3-year local recurrence rate was 4% for the group with a good (ie, mesorectal) plane of dissection compared with 13% for the group with a poor (ie, muscularis propria) plane of dissection (p = 0.003).109 Importantly, distal mesorectal spread of rectal cancer often extends further than distal intramural spread. Although distal intramural spread is relatively uncommon (found beyond 1 cm from the distal edge of the intraluminal cancer in only 4% to 10% of rectal cancers), deposits of distal mesorectal nodal spread can occur up to 3 to 4 cm distal to the primary cancer.110,111 To address the propensity for both intramural and mesorectal involvement, for tumors of the upper rectum, the mesorectal excision should typically extend 5 cm below the distal edge of the tumor; for tumors of the middle and lower rectum, a TME (ie, excision of all mesorectum to its most distal extent) is required with a distal rectal resection margin of, ideally, at least 2 cm. For tumors of the very distal rectum at or below the mesorectal margin, a mural margin of 1 cm appears acceptable in conjunction with a TME in appropriately selected patients.112 Even shorter distal margins may be acceptable in selected patients who are highly motivated for sphincter preservation and who have demonstrated favorable tumor regression after neoadjuvant therapy.113–115 In cases where preoperative anal function and distal pathologic clearance are adequate, TME may be followed by creation of an ultralow colorectal anastomosis or coloanal anastomosis. In cases where the tumor directly involves the anal sphincter or the levator muscles, where t
Search from 250 M+ research papersSearch from 250 M+ research papers
Aug 26, 2023
Nelya Melnitchouk + 6
Open Access