TES is a minimally invasive approach to local excision of rectal lesions. It has been used in benign conditions such as large rectal polyps (that cannot be removed through a colonoscope), retrorectal masses, rectal strictures, rectal fistulae, pelvic abscesses, and in malignant conditions (e.g., malignant polyps). Use of Transanal Endoscopic Microsurgery (TEMS) for resection of rectal cancers is more controversial. TEMS can avoid morbidity and mortality associated with major rectal surgery, including the fecal incontinence related to stretching of the anal sphincter, and can be performed under general or regional anesthesia.
The TEMS system has a specialized magnifying rectoscope with ports for insufflation, instrumentation, and irrigation. This procedure has been available for over 20 years in Europe but has not been widely used in the United States. Two reasons for this slow adoption are the steep learning curve for the procedure and the limited indications. For example, most rectal polyps can be removed endoscopically, and many rectal cancers need a wide excision and are thus not amenable to local resection.
Transanal minimally invasive surgery (TAMIS) was introduced in 2010 and utilizes a single incision laproscopic surgery port. The advantage of this technique is lower cost and ease of patient positioning. TAMIS appears to require less training and skill for surgeons already proficient in single incision laproscopic surgery due to its utilization of the same platform and instruments.
The most common treatment for rectal cancer is surgery; the technique chosen will depend on several factors. The size and location of the tumor, evidence of local or distal spread, and patient characteristics and goals are all attributes that will affect treatment approach. Open, wide resections have the highest cure rate but may also have significant adverse effects. Most patients find the potential adverse effects of lifelong colostomy and/or bowel, bladder, or sexual dysfunction acceptable in the face of a terminal illness. Laparoscopic-assisted surgery, with lymph node dissection as indicated, is technically difficult in the pelvic region but is being investigated as a less invasive alternative to open resection.
Local excision alone does not offer the opportunity for lymph node biopsy and therefore has been reserved for patients in whom the likelihood of cancerous extension is small. local excision can occur under direct visualization in rectal tumors within 10 cm of the anal verge. TEMS extends local excision ability to the proximal rectosigmoid junction. Adenomas, small carcinoid tumors, and nonmalignant conditions (e.g., strictures, abscesses) are amenable to local excision by either method.
The use of local excision in rectal adenocarcinoma is an area of much interest and may be most appropriate in small tumors (<4 cm) confined to the submucosa (T1, as defined by the TNM staging system). Presurgical clinical staging, however, may miss up to 15% of regional lymph node spread. During local excision, the excised specimen should be examined by a pathologist; if adverse features such as high-grade pathology or unclear margins are observed, the procedure can be converted to a wider resection. Despite this increased risk of local recurrence, local excision may be an informed alternative for patients. TEMS permits local excision beyond the reach of direct visualization equipment.
Barendse et al (2011) reported on a systematic review compared TEMS with endoscopic mucosal resection (EMR) for rectal adenomas larger than 2 cm.1 Included in the review were 48 TEMS and 20 EMR studies; all were treated as single-arm studies. No controlled trials were identified that compared TEMS with EMR directly. Early adenoma recurrence rates, within 3 months of the procedure, were 5.4% (95% confidence interval [CI], 4.0% to 7.3%) with TEMS and 11.2% (95% CI, 6.0% to 19.9%) with EMR (p=0.04) in pooled estimates. After 3 months, late adenoma recurrence rates in pooled estimates were 3.0% (95% CI, 1.3% to 6.9%) with TEMS and 1.5% (95% CI, 0.6% to 3.9%) for EMR (p=0.29). Lengths of hospitalization and readmission rates did not differ significantly between procedures. For TEMS, mean hospital length of stay was 4.4 days and 2.2 days for EMR (p=0.23). Hospital readmission rates were 4.2% for TEMS and 3.5% for EMR (p=0.64). Complication rates after TEMS, for rectal adenomas only, were 13.0% (95% CI, 9.8% to 17.0%) and 3.8% (95% CI, 2.8% to 5.3%) after EMR, for colorectal adenomas (p<0.001). Postoperative complications increased significantly with larger polyp size (p=0.04). However, postoperative complication rates remained higher for TEMS after adjusting for a larger mean polyp size in the TEMS studies (8.7%; 95% CI, 5.8% to 12.7%) than in EMR studies (4.2%; 95% CI, 2.9% to 6.3%; p=0.007). These results would suggest that TEMS may be associated with lower early cancer recurrence than with EMR but late cancer recurrence (after 3 months) may not differ significantly between procedures. Complications were significantly higher with TEMS for rectal adenomas larger than 2 cm. This systematic review was limited by the low quality of the available studies, particularly on the single-arm study evidence base.
Middleton et al (2005) conducted a systematic review of TEMS based on published results through August 2002.2 Three comparative studies, including a randomized controlled trial (RCT), and 55 case series were included. The first area of study was the safety and efficacy in the removal of adenomas. In the RCT, no difference could be detected in the rate of early complications between TEMS (10.3% of 98 patients) and direct local excision (17% of 90 patients) (relative risk, 0.61; 95% CI, 0.29 to 1.29). TEMS resulted in lower local recurrence (6% [6/98]) than direct local excision (22% [20/90]) (relative risk, 0.28; 95% CI, 0.12 to 0.66). The 6% local recurrence rate for TEMS in this trial is consistent with rates found in TEMS case series.
Al-Najami et al (2016) reported on longer term follow-up for a prospective cohort study of 280 patients with advanced polyps and early rectal cancer treated with TEMS.16 Most patients (n=163 [63%]) had benign disease. Postoperative complications were more frequent in malignant cases (24.0%) than in benign cases (10.8%; p=0.03). A standard follow-up protocol was followed by 83% and 85% of benign and malignant cases, respectively. Over a mean follow-up of 16.4 and 15.2 months in the benign and malignant groups, recurrence rates were 8.3% and 13.5%, respectively.
A meta-analysis by Lu et al (2015) compared TEMS with total mesorectal excision for T1 rectal cancer.17 Studies selected included 1 RCT and 6 non-RCTs (303 treated with TEMS; 557 treated with total mesorectal excision). For the outcome of postoperative recurrence, the rate of local recurrence was higher after TEMS (odds ratio [OR], 4.63; 95% CI, 2.03 to 10.53; p<0.001, I2=0%). For the 6 studies reporting on OS, there were no significant differences between the TEMS and total mesorectal excision groups (OR=0.87; 95% CI, 0.55 to 1.38; p=0.55, I2=0%).
Clancy et al (2015) published a systematic review of the comparative efficacy of TEMS and standard transanal excision (TAE) for early rectal cancer.18 Six studies including outcomes for 927 excisions were selected, all of which were nonrandomized. On combined analysis, TEMS had a higher rate of negative surgical margins (OR=5.3; 95% CI 3.2 to 8.7) and a lower rate of recurrence (OR=0.25; 95% CI, 0.15 to 0.40) compared with standard excision. Complication rates did not differ significantly between techniques (OR=1.018; 95% CI, 0.658 to 1.575).
Sajid et al (2014) reported on a systematic review and meta-analysis of TEMS and radical resection for stage T1 and T2 rectal cancers.19 Included in the review were 5 RCTs and 5 cohort studies (445 TEMS patients, 438 radical resection patients). In random-effects models, there was a greater risk of local recurrence with TEMS than with radical resection (OR=2.78; 95% CI, 1.42 to 5.44; p<0.003) and a greater risk of overall recurrence (OR=2.01; 95% CI, 1.18 to 3.42; p<0.01). The risk of distant recurrence did not differ significantly between procedures (OR=0.87; 95% CI, 0.41 to 1.83; p=0.71) nor did OS rates (OR=0.90; 95% CI, 0.49 to 1.66; p=0.74). In a subgroup analysis of the 5 RCTs, the risk of overall recurrence remained higher with TEMS (OR=2.21; 95% CI, 1.10 to 4.41; p<0.03). OS rates, however, did not differ significantly between TEMS and radical resection (OR=0.80; 95% CI 0.43 to 1.47; p=0.47), and postoperative complications were significantly lower with TEMS (OR=0.19; 95% CI, 0.08 to 0.44; p<0.001).
Wu et al (2011) published a meta-analysis on TEMS and conventional surgery for stage T1 rectal cancers.20 Five studies were selected, including a prospective RCT and 4 retrospective, nonrandomized studies for a total of 397 (216 TEMS, 181 conventional rectal surgery) patients. Combined analyses were performed for mortality, postoperative complications, recurrence rates, and 5-year survival. No deaths were reported from either procedure, and TEMS had fewer postoperative complications (16/196) than conventional surgery (77/163). On combined analysis, the odds for complications was 0.10 (95% CI, 0.05 to 0.18). There was a higher rate of local recurrence or distant metastasis at 40-month follow-up for TEMS (12% [26/216]) than for conventional radical surgery (0.5% [1/181]). On combined analysis, the odds for recurrence in the conventional surgery group was 8.64 (95% CI, 2.63 to 28.39). The 5-year survival (not specified as disease-specific or overall), as reported in 4 studies, did not differ significantly between groups (80.1% [157/196] for TEMS vs 81% [132/163] for conventional surgery). These results supported the conclusion that TEMS is associated with fewer early complications but higher rates of recurrence than standard resection, with no demonstrable differences in open surgery (OS).
Sgourakis et al (2011) conducted a meta-analysis of stage T1 and T2 rectal cancer treatment that compared TEMS with standard resection and TAE.21 Eleven studies were selected for analysis and included 3 randomized controlled, 1 prospective, and 7 retrospective trials (total N=1191 patients; 514 TEMS, 291 standard resections, 386 TAE). Numerous combined analyses were performed to measure mortality, complications, and recurrence rates. For postoperative complication rates, combined analysis showed a significantly lower rate of major complications for TEMS than for standard resection (OR=0.24; 95% CI, 0.07 to 0.91). Minor complications did not differ significantly between groups. Overall postoperative complications did not differ significantly between TEMS and TAE when stage T1 and T2 tumor data were pooled. Follow-up for all studies was a mean or median of more than 30 months (except for follow-up >20 months in 1 treatment arm in 2 studies). For T1 tumors, local recurrence was significantly higher for the TEMS group than for the standard resection group (OR=4.92; 95% CI, 1.81 to 13.41), as was overall recurrence (OR=2.03; 95% CI, 1.15 to 3.57). Distant metastasis (OR=1.05; 95% CI, 0.47 to 2.39) and OS (OR=1.14; 95% CI, 0.55 to 2.34) did not differ significantly between groups. Results were similar when data were analyzed for T1 and T2 tumors, except that disease-free survival was significantly longer with TEMS than with TAE. There was less evidence for T2 tumors, and conclusions for that group of patients were less clear. The results of this review also supported conclusions that TEMS is associated with fewer postoperative complications than standard resection, higher local and distant recurrence rates, and no differences in the long-term OS.
Doornebosch et al (2009) discussed weaknesses in the evidence and unresolved issues about the role of TEMS.22 Reviewers posed 3 questions: “First, is there enough evidence to propagate LE [local excision] as a curative option in selected (T1) rectal carcinomas? Second, if LE is justified, which technique should be the method of choice? Third, can we adequately identify, pre- and postoperatively, tumors suitable for LE?” They noted that selection bias in studies complicated answering the first question; and a significant portion of tumors recurred in all studies using various techniques for LE (including TEMS), although it seemed not to influence survival rates. Reviewers noted that the published case series reporting outcomes after TEMS for T1 rectal carcinomas used inclusion criteria that were not always clear and used salvage procedures that could introduce bias. TEMS was demonstrated to be a safe procedure in all series; complication rates varied between 5% and 26%, and complications were generally minor. Local recurrence rates for TEMS varied between 4% and 33% in the studies reviewed. On the third question, reviewers assessed whether high recurrence rates could be improved by better tumor selection. They noted that TEMS had been incorporated into surgical practice based largely on retrospective case series, and noted that, despite the lack of level I evidence, its use seemed justified in well-selected T1 rectal cancers. They also indicated that some view TEMS as an alternative for patients with T1 lesions who are currently undergoing other methods of LE (eg, using the Parks technique instead of radical surgery).
E. Lezoche et al (2012) published an RCT of 100 patients with T2 rectal cancers without evidence of lymph node or distant metastasis randomized to TEMS or laparoscopic total mesorectal excision.23 All patients also received neoadjuvant chemoradiation before surgery. All patients in the TEMS group completed the procedure. With laparoscopic resection, 5 (10%) patients required conversion to open surgery (p=0.028), and 23 patients required a stoma. Postoperative complications did not differ significantly between groups. Disease-free survival also did not differ significantly between groups (p=0.686) at a median follow-up of 9.6 years (range, 4.7-12.3 years for laparoscopic resection; range, 5.5-12.4 years for TEMS). Local recurrence or metastases occurred in 6 TEMS patients and 5 laparoscopic patients.
G. Lezoche et al (2008) reported on a similar RCT evaluating of 70 subjects with stage T2 rectal cancer without evidence of lymph node or distant metastasis on imaging.24Patients were randomized to TEMS or laparoscopic resection via total mesorectal excision. All patients received chemoradiation before surgery. Median follow-up was 84 months (range, 72-96 months). Two (5.7%) local recurrences were observed after TEMS and 1 (2.8%) after laparoscopic resection. Distant metastases occurred in 1 patient in each group. The probability of survival from rectal cancer was 94% for both groups. Overlap of patients studied in the 2008 and 2012 trials could not be determined.
A large number of case series and retrospective nonrandomized comparative reviews have been published.3-13 The case series offer useful information on the completeness of resection, local recurrence, and complications, but does not provide definitive evidence on the comparative efficacy of TEMS because the comparisons were limited by potential selection bias leading to differences in patient characteristics.
Much of the research has focused on the technical aspects of TEMS and on other, non-neoplastic applications. Other studies have investigated the use of TEMS with adjuvant therapy or additional techniques. For example, Walega et al (2010) reported on a small study that added endoscopic mesorectum resection to TEMS.25
Moore et al (2008) retrospectively reviewed patients who underwent TAE for rectal neoplasms and compared results for traditional transanal resection with TEMS.26 Of 296 patients identified, 76 were excluded because of surgery due to abscesses, fistulas, inflammatory bowel disease, or multiple lesions. Forty-nine patients were excluded because of incomplete or missing charts. Records of 171 patients were analyzed; 82 patients who underwent TEMS and 89 who had a transanal resection. For patients who received TEMS, those with stage T1 lesions without adverse histologic features (poor differentiation, lymphovascular invasion) received local excision alone. Patients with T1 lesions with adverse features or T2 lesions received postoperative chemoradiation. Local excision was performed for T3 lesions only in high-risk patients or those who refused radical resection. In the TEMS group, there were 40 polyps, 5 carcinoma in situ, 21 T1 lesions, 7 T2 lesions, 8 T3 lesions, no indeterminate lesions, and 1 carcinoid lesion; in the transanal resection group, there were: 38 polyps, 4 carcinoma in situ, 20 T1 lesions, 19 T2 lesions, 6 T3 lesions, 1 indeterminate lesion, and 1 carcinoid lesion. There were 12 (15%) postoperative complications (4 major) in the TEMS group and 15 (17%) complications in the transanal resection group (6 major). In the TEMS group, 90% had negative tumor margins, and none had indeterminate margins vs 71% negative and 15% indeterminate margins in the transanal resection patients. Local recurrence was less frequent after TEMS (4%) than after transanal resection (24%; p=0.004). The difference between groups in distant recurrence was not statistically significant. Three TEMS patients with malignant lesions underwent radical resection and were excluded from recurrence analyses. The recurrence rate among cancer patients did not differ statistically between groups. For patients with adenomas, the overall recurrence rate after TEMS was 3% and 32% for transanal resection. In patients with polyps, clear margins were achieved more frequently after TEMS (83%) than after transanal resection (61%).
A number of studies identified have raised questions about disease recurrence after TEMS for stage T1 rectal cancer.27-29 For example, Doornebosch et al (2010) reported on TEMS for 88 patients, 18 (20.5%) of whom had a local recurrence.27 Of them, 16 patients had salvage surgery. At the 3-year follow-up, the OS rate was 31%, and the cancer-related survival rate was 58%. Authors concluded that further tailoring patient and tumor selection before a decision for LE might improve survival.
In an editorial accompanying this study, Friel (2010) commented on the use of LE in the treatment of T1 rectal lesions.30 He noted that the reported recurrence rate should raise concerns and calls for additional studies of recurrence with LE to verify the Doornebosch findings. Friel also noted that LE must still be considered as an oncologic compromise between lower surgical morbidity but higher disease recurrence and that, once fully informed, patients may find this compromise acceptable.
National Comprehensive Cancer Network
The National Comprehensive Cancer Network (NCCN) guidelines on the treatment of rectal cancer (v.3.2018) state that, when criteria for transanal resection are met, TEMS can be used when the tumor can be adequately identified in the rectum.31 The Network further states that TEMS for more proximal lesions (>8 cm from anal verge) may be technically feasible. The guidelines are based on level 2A evidence.
National Cancer Institute
The 2018 National Cancer Institute (NCI; 2018) guidelines on treatment of rectal cancer indicate the management of rectal cancer is multimodal and involves a multidisciplinary team of cancer specialists with expertise in gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology.32 Based on the increased risk of local recurrence and poor overall prognosis, management of rectal cancer diverges from colon cancer. The differences include surgical technique, use of radiotherapy, and method of chemotherapy administration. Additional issues are maintenance or restoration of the normal anal sphincter and genitourinary function. NCI recommends as a primary treatment for patients with rectal cancer surgical resection of the primary tumor. NCI guidance specific to this evidence review includes “…Transanal local excision and transanal endoscopic microsurgery for select clinically staged T1/T2 N0 rectal cancers."
American Society of Colon and Rectal Surgeons
The American Society of Colon and Rectal Surgeons (2013) updated its 2010 practice parameters for the management of rectal cancer.33 The 2013 guidelines indicated that curative local excision is an appropriate treatment modality for carefully selected, well to moderately differentiated T1 rectal cancers. Tumor size must be less than 3 cm in diameter and less than one-third of the bowel lumen circumference. Additionally, patients must not have lymphovascular or perineural invasion. The guidelines noted that visualization with TEMS appears to be superior to the transanal approach, but randomized controlled trials are lacking. T2 lesions should be treated with radical mesenteric excision unless the patient is a poor candidate for a more extensive surgical procedure.
American College of Radiology
The American College of Radiology (ACR; 2015) updated its 2010 appropriateness criteria on local excision of early-stage rectal cancer.34,35 ACR noted that TEMS is an appropriate operative procedure for locally complete excision of distal rectal lesions and has been “evaluated for curative treatment of invasive cancer.” ACR also noted that TEMS has “been shown to be as effective, and associated with less morbidity than conventional transanal excision” and is considered safe after treatment with chemoradiation. These ACR guidelines were based on expert consensus and analysis of current literature.
In March 2001, the TEMS Combination System and Instrument Set (Richard Wolf Medical Instruments) was cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process. FDA determined that this device was substantially equivalent to existing devices for use in inflating the rectal cavity, endoscopically visualizing the surgical site, and accommodating up to 3 surgical instruments. In 2011, the SILS™ Port (Covidien) was cleared for marketing by FDA through the 510(k) process. The SILS™ Port is a similar instrument that can be used for rectal procedures including TEMS. Another device determined by the FDA to be substantially equivalent to these devices is the GelPOINT® Path (Applied Medical Resources). FDA product codes: HIF, GCJ, FER.