Conventional transanal excision (TAE) with retractors has been widely considered a valid oncological option for the treatment of early rectal cancers until the 1990s, when the widespread diffusion of the total mesorectal excision (TME) (1) and the implementation of new endoscopic rigid platforms, such as transanal endoscopic microsurgery (TEM) and transanal endoscopic operation (TEO) have raised substantial questions about the radicality of TAE.
Designed by Buess in the early 1980s, TEM has progressively replaced TAE for the local excision of selected early rectal cancers, showing significantly better early short-term outcomes and better fecal and urogenital outcomes than abdominal rectal resection with TME (2); in addition, it became clear that the quality of the excision performed with TEM was significantly better than with TAE, with subsequent lower rates of local relapse and longer survival (3).
More recently, the rigid TEO platform has been conceived, reporting similar outcomes when compared to the original rigid TEM platform (4).
This paper aims at reviewing the outcomes of local excision with rigid platforms (TEM/TEO) for rectal cancer.
There are two rigid platforms available on the market to perform transanal endoscopic surgery for cancers of the rectum: the TEM and the TEO platforms. Both let the surgeon excise tumors that are sited in the lower, mid and upper rectum, providing a significantly better visualization of the operative field than conventional TAE. Current indications to perform a transanal endoscopic procedure by using a rigid platform with a radical intent are similar to those using a soft platform: large rectal adenomas not suitable for endoscopic resection and rectal cancers staged as cT1N0 preoperatively. Preoperative work-up does not differ between patient candidate to TEM/TEO or anterior resection: endoscopic ultrasound is obtained to evaluate the depth of rectal wall invasion, while a pelvic magnetic resonance imaging (MRI) is performed to rule out the presence of suspected enlarged lymph nodes in the mesorectum.
The TEM (Richard Wolf, Knittlingen, Germany) equipment was originally conceived by Gerhard Buess in the early 80s and comprises:
- An operating rigid rectoscope that is 4 cm in diameter and is available in three different lengths with correspondent obturators that allow insertion of the rectoscope through the anus.
- A working adapter and a working insert to connect the rectoscope to working instruments, camera and insufflator.
- A Martin arm to fix the rectoscope to the operating table.
- A light source and a stereoscopic angled telescope which allows dissection under microsurgical conditions with 3D visualization.
- The surgical tools include suction and irrigation tubes, curved and straight monopolar grasping forceps, suture clips forceps, electrocautery, needle holder.
The TEO Instrumentation (Karl Storz GmbH, Tuttlingen, Germany) is an alternative to the TEM platform that has gained wide acceptance worldwide. TEO instrumentation includes a proctoscope (7 or 15 cm in length, 4 cm in diameter), three operative channels (12, 5 and 5 mm in diameter) for dedicated or conventional laparoscopic tools, and a channel (5 mm in diameter) for a 30° 2D camera. The tip of the TEO rectoscope has a particular shape that let the surgeon manipulate rectal tissues and suture the rectal wall circumferentially. The images of the surgical field are displayed on a screen by using a standard laparoscopic unit.
Surgical technical points
Positioning of the patient on the operative table
All patients that are candidate to TEM or TEO start a low-fiber content diet the week before surgery, and receive a rectal enema 12 and 2 hours preoperatively.
The patient is lies on the operative table either in the prone or supine position, thus keeping the rectal tumor at the 6 o’clock position. Patients with rectal cancer arising from the lateral wall also lay in the supine position; they are placed prone only when the tumor is sited on the anterolateral rectal wall or close to the peritoneal reflection. In case of opening of the peritoneum, having the patient prone prevent the small bowel from entering the rectum and the air leak into the peritoneal cavity, thus facilitating the closure by suture of the peritoneal defect.
Both TEM and TEO procedures can be performed either under general or spinal anesthesia (SA) (5-7). A recent prospective observational including 50 patients treated with TEO platform for rectal tumors showed that TEO® under spinal anaesthesia is safe and feasible. No intraoperative complications occurred, and no procedure required conversion to general anesthesia (GA). Median operative time was 60 (range, 20–165) min. No patients required opioids postoperatively. No significant postoperative changes were observed in hemodynamic parameters (7). The same group published a few months ago the results of a retrospective study aiming at comparing spinal and GA (8). A total of 148 patients were included: 77 had GA and 71 SA. None patients receiving SA required GA. Length of hospital stay was shorter in the SA group (3 vs. 4 days, P=0.0201). Patients mobilization occurred earlier in the SA group, as well as resumption of oral intake (18 vs. 24 hours and 24 vs. 48 hours, respectively, P<0.0001). Operating room occupancy time was longer in the GA group (120 vs. 100 minutes, P=0.0008). There were no differences in postoperative complications, postoperative nausea, vomiting and pain between the two groups. Percentage of patients requiring postoperative rescue therapy with tramadol was similar between groups, but SA patients received a lower opioid dosage (176.6±67.8 vs. 238.3±79.5 mg, P=0.0011). Based on these findings, SA should be considered the treatment of choice, when not contraindicated, in patients undergoing TEM or TEO, since it leads to reduced perioperative opioid consumption and a faster postoperative recovery.
Step 1: dissection
After the rectoscope has been inserted into the rectum and the rectal cancer identified, the rectoscope is fixed to the operating table. Endorectal carbon dioxide (CO2) pressure is kept stable at 8 mmHg.
- The tumor is marked circumferentially by using monopolar electrocautery, thus ensuring at least 5-mm clear circumferential margins.
- The dissection is started from the lower margin of the rectal cancer, and then is continued proximally around and under the tumor until a circumferential dissection is achieved and the tumor en bloc excised. Tumor excision can be safely performed by using monopolar electrocautery. Ultrasonic shears or an electrothermal bipolar vessel sealing system might be useful in difficult cases to complete the dissection. Due to the limited accuracy of the preoperative staging tools, a full-thickness excision down to the perirectal fatty tissue should be routinely performed. Female and male patients who had previous prostatectomy who undergo a TEM/TEO procedure for an anteriorly located rectal tumor are at higher risk of developing a rectovaginal or rectovesical fistula.
- The specimen is then removed through the anus.
- Although TEM was initially developed for the excision of large adenomas or early cancers arising from the mid and lower rectum, the distance of rectal cancer from the anal verge does not represent a contraindication to a transanal endoscopic procedure. There are several data supporting the use of a rigid platform also for the treatment of selected intraperitoneal rectal cancers, with no increased short-term morbidity or mortality and no adverse oncologic outcomes even in case of inadvertent peritoneal opening (9-15). In our experience, the prone position of the patient on the operating table and the particular shape of the tip of the TEO proctoscope help suture the rectal wall on a 360° surface, thus minimizing the risk of conversion to open surgery or the need for a stoma.
Step 2: wall defect suturing
The optimal management of the rectal wall defect is controversial, with some studies suggesting the closure, others favouring leaving the defect open and others showing no differences. Menahem et al. (16) recently performed a meta-analysis of the literature including 4 studies. A total of 489 patients were considered: 317 had the defect closed and 182 had the defect left open). There were no differences in terms of overall morbidity (11% vs. 15.4%), postoperative local infection (3.1% vs. 4.9%), postoperative bleeding (5.6% vs. 7.7%) and reintervention (1.9% vs. 1.1%). Major limitations in the 4 studies included were different perioperative management protocols, different surgeon experience, different types of tools used for the tumor dissection and the distance of the rectal lesion from the anal verge.
Similar outcomes were observed by Lee et al. (17) in a multi-institutional matched analysis published in 2018, suggesting that the decision to close the rectal wall defect should represent a tailored approach. The authors analysed the data of adult patients undergoing local excision from 2004 to 2016 in three institutions in the United States, performing a propensity score matching in one-to-one fashion. The defect closure was performed at the surgeon’s discretion. A total of 220 patients were included: 110 in both groups. There were no significant differences in terms of overall 30-day postoperative morbidity between patients with open or closed rectal wall defect after full-thickness or partial excision (15% vs. 12%, P=0.432 and 7% vs. 5%, P=0.552). The only complication that occurred more frequently in the group of patients with the rectal defect left open was bleeding: 9% vs. 3%, P=0.045). However, the closure of the defect was not independently associated with any postoperative complications.
We think that the opportunity to close the rectal wall defect is one of the points of strength of TEM/TEO platform compared to classical TAE and might lower the morbidity rates in those patients who further undergo abdominal rectal resection with TME after local excision. A prospective study has demonstrated that the rate of grade 3 complications according to the Clavien Dindo classification was significantly reduced when the rectal wall defect was sutured by TEM (18).
- The wall defect is first irrigated with iodopovidone solution to reduce septic complications and the risk of tumor cell implantation.
- The rectal wall defect is then closed by using a running suture that are secured by dedicated silver clips.
Postoperative complications occur in 2% to 15% of patients. Rectal bleeding and dehiscence of the rectal wall suture are the most common complications after a TEM/TEO procedure. Rectal bleeding tends to self-limit in the vast majority of patients. In case of persistent and copious bleeding blood transfusions and endoscopic clipping represent the optimal treatment modality. The breakdown of the rectal wall suture is more commonly experienced by patients treated with neoadjuvant (chemo)radiation therapy for preoperatively staged as T2N0 rectal cancer. Patients with suture dehiscence experience severe rectal pain, tenesmus and fever. An endoscopy or cross-sectional imaging is usually performed to assess the entity of the dehiscence and the dimension of the perirectal fluid collection for possible drainage. The treatment is most often conservative, including intravenous antibiotic therapy and 10% iodine solution enemas, with a healing rate of about 90% (19). Further treatment tools such as the endoscopic vacuum system (Endosponge®, B Braun Medical BV, Melsungen AG, Tuttlingen, Germany) are rarely use. The need for a stoma creation to control sepsis is very uncommon.
TEM or TEO?
There is only one randomized controlled trial comparing TEM and TEO for rectal neoplasms. Serra-Aracil et al. (4) enrolled patients with a rectal adenoma or cancer preoperatively staged T1–2 N0, 2 to 6 cm in diameter, located in the mid and lower rectum (2–15 cm). A total of 34 patients were randomized: 17 patients in the TEM group and 17 in the TEO group. Time necessary to assemble the instrumentation, time necessary for excision and rectal wall suturing and total operative time were not significantly different. No conversion from one platform to the other or to abdominal surgery was necessary. Similar postoperative morbidity rates were observed: 21% after TEM and 18% after TEO (P=0.83). There was no mortality and median hospital stay was 3 days in both groups. Mean costs associated with TEO were significantly lower than those associated with TEM (€2,031±€440 vs. €2,603±€507, P=0.003).
Local excision for selected rectal cancers: the evidence
The current evidence from several studies comparing TEM and TAE for T1 N0 rectal cancers shows significantly higher and unacceptable local recurrence rates after TAE than TEM, secondary to higher rates of specimen fragmentation and positive resection margins (3,20,21). The evidence that TAE jeopardizes long-term oncologic outcomes in patients with early rectal cancer has led to a shift towards the use of rigid platforms during the last 15 years (22,23). Several studies have demonstrated that the transanal endoscopic surgery with rigid platforms does not compromise the survival in “low risk” T1 carcinoma according to Hermanek criteria (24-27), keeping in mind that submucosal tumor invasion is one of the strongest independent risk factors for long-term failure in T1 N0 patients (28,29).
The risk of lymph node metastases increases with rectal cancer stage, ranging from 0-3% in case of T1 sm1, 15% in T1 sm2–3 to 25% in T2 cancers (30,31). As a consequence, the risk of local and distant relapse is significantly higher in “high risk” T1 and T2 rectal cancer patients after local excision than after radical rectal resection with TME.
When final pathology of the TEM/TEO specimen reveal the presence of a high risk pT1 or a more invasive rectal cancer, a further rectal resection with TME achieves excellent oncologic outcomes (27,32), even though it is more technically difficult and the risk of a definitive stoma is higher (33).
A multimodal organ-preserving approach including neoadjuvant chemoradiation therapy followed by local excision by TEM has been proposed in selected patients with T1–2 N0 rectal cancer, thus aiming at reducing the risk of complications that burden radical abdominal rectal surgery, without jeopardizing the oncologic outcomes (26,34-37). Even though the preliminary oncologic results of this strategy seem promising, significant rectal wound-related morbidity (19,38,39) and poor functional outcomes (40,41) have been reported in patients undergoing neoadjuvant treatment followed by TEM. The high complication rates, ranging between 25% and 70%, are mainly related to the fact that the suture of the rectal wall involves irradiated tissue.
Transanal endoscopic surgery with rigid platforms is the modality of choice for local excision of selected rectal cancers; conventional TAE with retractors is indicated only in highly selected distal rectal tumors if the insertion of the platform is not feasible for technical reasons. The role of neoadjuvant treatment in association with TEM/TEO in highly selected patients with clinically staged T2 N0 rectal cancer is still under evaluation and should be proposed only within study protocols, until the results of large prospective randomized controlled trials will be published (42-44).
Conflicts of Interest: The authors have no conflicts of interest to declare.
- Heald RJ, Moran BJ, Ryall RDH, et al. The Basingstoke experience of total mesorectal excision, 1978–1997. Arch Surg 1998;133:894-9. [Crossref] [PubMed]
- Allaix ME, Rebecchi F, Giaccone C, et al. Long-term functional results and quality of life after transanal endoscopic microsurgery. Br J Surg 2011;98:1635-43. [Crossref] [PubMed]
- Clancy C, Burke JP, Albert M, et al. Transanal Endoscopic Microsurgery versus standard transanal excision for the removal of rectal neoplasms: a systematic review and meta-analysis. Dis Colon Rectum 2015;58:254-61. [Crossref] [PubMed]
- Serra-Aracil X, Mora-Lopez L, Alcantara-Moral M, et al. Transanal endoscopic microsurgery with 3-D (TEM) or high-definition 2-D transanal endoscopic operation (TEO) for rectal tumors. A prospective, randomized clinical trial. Int J Colorectal Dis 2014;29:605-10. [Crossref] [PubMed]
- Hayashi S, Takayama T, Yamagata M, et al. Single-incision laparoscopic surgery used to perform transanal endoscopic microsurgery (SILSTEM) for T1 rectal cancer under spinal anesthesia: report of a case. Surg Today 2013;43:325-8. [Crossref] [PubMed]
- Lee TG, Lee SJ. Transanal single-port microsurgery for rectal tumors: minimal invasive surgery under spinal anesthesia. Surg Endosc 2014;28:271-80. [Crossref] [PubMed]
- Arezzo A, Cortese G, Arolfo S, et al. Transanal Endoscopic Operation under spinal anaesthesia. Br J Surg 2016;103:916-20. [Crossref] [PubMed]
- Cortese G, Sales G, Maiolo G, et al. Effectiveness of spinal anaesthesia in transanal endoscopic microsurgery: a 3-year experience. Minerva Anestesiol 2018. [Epub ahead of print]. [PubMed]
- Gavagan JA, Whiteford MH, Swanstrom LL. Full-thickness intraperitoneal excision by transanal endoscopic microsurgery does not increase short-term complications. Am J Surg 2004;187:630-4. [Crossref] [PubMed]
- Ramwell A, Evans J, Bignell M, et al. The creation of a peritoneal defect in transanal endoscopic microsurgery does not increase complications. Colorectal Dis 2009;11:964-6. [Crossref] [PubMed]
- Baatrup G, Borschitz T, Cunningham C, et al. Perforation into the peritoneal cavity during transanal endoscopic microsurgery for rectal cancer is not associated with major complications or oncological compromise. Surg Endosc 2009;23:2680-3. [Crossref] [PubMed]
- Morino M, Allaix ME, Famiglietti F, et al. Does peritoneal perforation affect short- and long-term outcomes after transanal endoscopic microsurgery? Surg Endosc 2013;27:181-8. [Crossref] [PubMed]
- Eyvazzadeh DJ, Lee JT, Madoff RD, et al. Outcomes after transanal endoscopic microsurgery with intraperitoneal anastomosis. Dis Colon Rectum 2014;57:438-41. [Crossref] [PubMed]
- Marks JH, Frenkel JL, Greenleaf CE, et al. Transanal endoscopic microsurgery with entrance into the peritoneal cavity: is it safe? Dis Colon Rectum 2014;57:1176-82. [Crossref] [PubMed]
- Salm R, Lampe H, Bustos A, et al. Experience with TEM in Germany. Endosc Surg Allied Technol 1994;2:251-4. [PubMed]
- Menahem B, Alves A, Morello R, et al. Should the rectal defect be closed following transanal local excision of rectal tumors? A systematic review and meta-analysis. Tech Coloproctol 2017;21:929-36. [Crossref] [PubMed]
- Lee L, Althoff A, Edwards K, et al. Outcomes of Closed Versus Open Defects After Local Excision of Rectal Neoplasms: A Multi-institutional Matched Analysis. Dis Colon Rectum 2018;61:172-8. [Crossref] [PubMed]
- Marques CF, Nahas CS, Ribeiro U Jr, et al. Postoperative complications in the treatment of rectal neoplasia by transanal endoscopic microsurgery: a prospective study of risk factors and time course. Int J Colorectal Dis 2016;31:833-41. [Crossref] [PubMed]
- Marks JH, Valsdottir EB, DeNittis A, et al. Transanal endoscopic microsurgery for the treatment of rectal cancer: comparison of wound complication rates with and without neoadjuvant radiation therapy. Surg Endosc 2009;23:1081-7. [Crossref] [PubMed]
- Langer C, Liersch T, Süss M, et al. Surgical cure for early rectal carcinoma and large adenoma: transanal endoscopic microsurgery (using ultrasound or electrosurgery) compared to conventional local and radical resection. Int J Colorectal Dis 2003;18:222-9. [PubMed]
- Christoforidis D, Cho HM, Dixon MR, et al. Transanal endoscopic microsurgery versus conventional transanal excision for patients with early rectal cancer. Ann Surg 2009;249:776-82. [Crossref] [PubMed]
- Atallah S, Keller D. Why the Conventional Parks Transanal Excision for Early Stage Rectal Cancer Should Be Abandoned. Dis Colon Rectum 2015;58:1211-4. [Crossref] [PubMed]
- Gillern SM, Mahmoud NN, Paulson EC. Local excision for early stage rectal cancer in patients over age 65 years: 2000-2009. Dis Colon Rectum 2015;58:172-8. [Crossref] [PubMed]
- Hermanek P, Gall FP. Early (microinvasive) colorectal carcinoma. Pathology, diagnosis, surgical treatment. Int J Colorectal Dis 1986;1:79-84. [Crossref] [PubMed]
- Heintz A, Mörschel M, Junginger T. Comparison of results after transanal endoscopic microsurgery and radical resection for T1 carcinoma of the rectum. Surg Endosc 1998;12:1145-8. [Crossref] [PubMed]
- Lee W, Lee D, Choi S, et al. Transanal endoscopic microsurgery and radical surgery for T1 and T2 rectal cancer. Surg Endosc 2003;17:1283-7. [Crossref] [PubMed]
- Borschitz T, Heintz A, Junginger T. The influence of histopathologic criteria on the long-term prognosis of locally excised pT1 rectal carcinomas: results of local excision (transanal endoscopic microsurgery) and immediate reoperation. Dis Colon Rectum 2006;49:1492-506. [Crossref] [PubMed]
- Bach SP, Hill J, Monson JR, et al. A predictive model for local recurrence after transanal endoscopic microsurgery for rectal cancer. Br J Surg 2009;96:280-90. [Crossref] [PubMed]
- Morino M, Allaix ME, Caldart M, et al. Risk factors for recurrence after transanal endoscopic microsurgery for rectal malignant neoplasm. Surg Endosc 2011;25:3683-90. [Crossref] [PubMed]
- Yamamoto S, Watanabe M, Hasegawa H, et al. The risk of lymph node metastasis in T1 colorectal carcinoma. Hepatogastroenterology 2004;51:998-1000. [PubMed]
- Saraste D, Gunnarsson U, Janson M. Predicting lymph node metastases in early rectal cancer. Eur J Cancer 2013;49:1104-8. [Crossref] [PubMed]
- Levic K, Bulut O, Hesselfeldt P, et al. The outcome of rectal cancer after early salvage TME following TEM compared with primary TME: a case-matched study. Tech Coloproctol 2013;17:397-403. [Crossref] [PubMed]
- Morino M, Allaix ME, Arolfo S, et al. Previous transanal endoscopic microsurgery for rectal cancer represents a risk factor for an increased abdominoperineal resection rate. Surg Endosc 2013;27:3315-21. [Crossref] [PubMed]
- Lezoche E, Baldarelli M, Lezoches G, et al. Randomized clinical trial of endoluminal locoregional resection versus laparoscopic total mesorectal excision for T2 rectal cancer after neoadjuvant therapy. Br J Surg 2012;99:1211-8. [Crossref] [PubMed]
- Allaix ME, Arezzo A., Giraudo G, et al. Transanal endoscopic microsurgery vs. laparoscopic total mesorectal excision for T2N0 rectal cancer. J Gastrointest Surg 2012;16:2280-7. [Crossref] [PubMed]
- Sajid MS, Farag S, Leung P, et al. Systematic review and meta-analysis of published trials comparing the effectiveness of transanal endoscopic microsurgery and radical resection in the management of early rectal cancer. Colorectal Dis 2014;16:2-14. [Crossref] [PubMed]
- Garcia-Aguilar J, Renfro LA, Chow OS, et al. Organ preservation for clinical T2N0 distal rectal cancer using neoadjuvant chemoradiotherapy and local excision (ACOSOG Z6041): results of an open-label, single-arm, multi-institutional, phase 2 trial. Lancet Oncol 2015;16:1537-46. [Crossref] [PubMed]
- Perez RO, Habr-Gama A, São Julião GP, et al. Transanal Endoscopic Microsurgery for residual rectal cancer after neoadjuvant chemoradiation therapy is associated with significant immediate pain and hospital readmission rates. Dis Colon Rectum 2011;54:545-51. [Crossref] [PubMed]
- Arezzo A, Arolfo S, Allaix ME, et al. Results of neoadjuvant short-course radiation therapy followed by transanal endoscopic microsurgery for T1-T2 N0 extraperitoneal rectal cancer. Int J Radiat Oncol Biol Phys 2015;92:299-306. [Crossref] [PubMed]
- Gornicki A, Richter P, Polkowski W, et al. Anorectal and sexual functions after preoperative radiotherapy and full-thickness local excision of rectal cancer. Eur J Surg Oncol 2014;40:723-30. [Crossref] [PubMed]
- Restivo A, Zorcolo L, D’Alia G, et al. Risk of complications and long-term functional alterations after local excision of rectal tumors with transanal endoscopic microsurgery (TEM). Int J Colorectal Dis 2016;31:257-66. [Crossref] [PubMed]
- Morino M, Risio M, Bach S, et al. Early rectal cancer: the European Association for Endoscopic Surgery (EAES) clinical consensus conference. Surg Endosc 2015;29:755-73. [Crossref] [PubMed]
- Verseveld M, de Graaf EJ, Verhoef C, et al. Chemoradiation therapy for rectal cancer in the distal rectum followed by organ-sparing transanal endoscopic microsurgery (CARTS study). Br J Surg 2015;102:853-60. [Crossref] [PubMed]
- TREC study. Available online: https://www.birmingham.ac.uk/Documents/college-mds/trials/bctu/trec/TREC-protocol-v2.pdf
Cite this article as: Allaix ME, Arezzo A, Morino M. Transanal treatment of rectal cancer by rigid platform. Ann Laparosc Endosc Surg 2018;3:45.