European Journal of Cardiovascular Medicine

Rectal neoplasms are well-known premalignant lesions encountered with nearly 2.5% of these turning to the malignant stage. Hence, all the polyps must be removed and recurrence must be evaluated regularly. TEM (Transanal Endoscopic Microsurgery) is a minimally invasive modality that allows for precise and accurate resection of the rectal tumors situated 4-18 cm from the anal verge. This technique uses combined laparoscopy and endoscopy, protects the sphincter, and is tissue-sparing. It has been established that TEM is linked with lesser perioperative morbidity and mortality compared to transabdominal surgical approaches concerning sexual, bladder, and anorectal function.^1,2

The indications for TEM include removal of certain low-risk T1 carcinomas and a few of the adenomas, TEM is also chosen as a management modality for T2 rectal carcinoma in subjects with severe comorbidities ad where laparotomy and laparoscopy are contraindicated. Also, TEM is used in palliative management. Rigid proctosigmoidoscopy is done to assess the accessibility and position of the polyp. TRUS (TransRectal Ultrasound Examination) has shown >90% sensitivity in assessing the depth of penetration of rectal cancer.³

For staging the polyp after resection, MRI and TRUS can be used to assess the status of the lymph node and depth of penetration. Appropriate surveillance programs following TEM are still not well-defined and are associated with the recurrence risk for adenoma.⁴ The present study aimed to assess the complications and recurrence following polyp removal to assess the efficacy of transanal endoscopic surgery.

The present single-center clinical study aimed to assess the complications and recurrence following polyp removal to assess the efficacy of transanal endoscopic surgery. The study subjects were from the Outpatient Department of the Institute. Verbal and written informed consent were taken from all the subjects before study participation.

The study included subjects that underwent TEM at the institute within the defined study period and were under the ICD-10 code as Rectoscopic microsurgical excision of pathological tissue in the rectum. The data for all the subjects were gathered from medical files and data and all the histopathological data were also retrieved from institutional records.

The data retrieved from all the subjects also included demographics such as gender, age, TEM indication, and BMI. Data gathered for TEM were hospitalization duration, resection type (TEM assisted Endoscopic Submucosal Dissection (ESD) or TEM assisted Full Thickness Resection (FTR), surgery duration, and patient position during surgery. Histopathological and macroscopic polyp characteristics assessed included distance from the anal verge, adenoma types (villous, tubulovillous, tubular, and serrated) or adenocarcinoma, histopathologic free resection margins, Paris classification, macroscopic appearance, and polyp size.

Complications encountered in the study subjects were early postoperative complications seen within 30 days including perforation, urinary retention, abscess, and bleeding, and late complications that were seen after 30 days of surgery which included stenosis and incontinence to feces or flatus. Recurrence was defined as histopathological adenoma or adenocarcinoma recurrence at the previous site of resection at early assessment usually within 5 months following TEM.

Subjects referred for TEM underwent preoperative digital assessment, colonoscopy, TRUS, rectoscopy, and sigmoidoscopy. TEM indications were polyp site removal after endoscopic malignant polyp removal, residual or recurrence of adenomatous tissue following endoscopic polypectomy in the rectum (defined as 0 cm to 15 cm from the anal verge), and polyp size of a minimum of 2 cm. The exclusion criteria for the study were subjects where TEM was converted to an abdominal surgical approach. At TEM Day, subjects were given a rectal enema. For anaerobic and gram-negative strains, antibiotics such as metronidazole and gentamicin were given at the anesthesia start. Procedures were done using TEM under general anesthesia. TEM was performed as either FTR or TEM-assisted ESD.

FTR was considered when submucosal dissection was not feasible as in cases of re-resection of scar tissue or was not advisable as polyp site resection after endoscopic malignant polyp removal. Further details concerning surgical TEM technique were conventional. All cases except two were macroscopically confirmed as free from polyps by surgeons at the TEM procedure end. Postoperatively, there were no restrictions, and subjects were discharged in cases with no fever, no complications, and no suspicion of complications. Planning of regular controls was done as sigmoidoscopies 5 months after TEM. Individualized intensified control programs were made for subjects with adenocarcinomas and comprised of various combinations of CT scans, MRI, colonoscopies, sigmoidoscopies, and proctoscopies. 

The gathered were analyzed statistically using the chi-square test, Fisher’s exact test, Mann Whitney U test, and SPSS (Statistical Package for the Social Sciences) software version 24.0 (IBM Corp., Armonk. NY, USA) using ANOVA and student's t-test. The significance level was considered at a p-value of <0.05.

The present single-center clinical study aimed to assess the complications and recurrence following polyp removal to assess the efficacy of transanal endoscopic surgery. The present study assessed 224 subjects who underwent TEM at the Institute within the defined study period for spectroscopic microsurgical excision of pathological tissue in the rectum. The indications for TEM in study subjects were re-resection after polyp with adenocarcinoma, recurrence of benign polyp, primary polyp, and others in 10.7% (n=24), 11.6% (n=26), 75.9% (n=170), and 1.8% (n=4) subjects respectively. For resection type and radicality, TEM-assisted ESD, FTR, and other procedures were done in 39.3% (n=88), 58.9% (n=132), and 1.8% (n=4) subjects respectively. Macroscopically radical resection estimated by the surgeon was seen in 99.1% (n=222) of subjects. The mean distance from the anal verge was 14 cm, the mean polyp diameter was 30mm, the mean TEM duration was 60 minutes, and the mean hospitalization duration was 8.5 hours (Table 1).

On assessing the histopathological characteristics in study subjects, micro radical resection was done in 160 subjects and not started in 8 subjects where recurrence was seen in 12 and 0 subjects respectively. In 56 subjects with no microradical resection, recurrence was seen in 2 subjects. The mean polyp diameter was 30 mm with a range of 6-133mm. The most common polyp type was tubular seen in 100 subjects followed by tubulovillus in 52, adenocarcinoma in 34, villous in 6, and serrated and others in 4 subjects with recurrence in 10, 4, 0, 0, 0, and 0 subjects respectively (Table 2).

The study results showed that for TEM ESD (endoscopic submucosal dissection) and FTR in study subjects, the mean polyp diameter in TEM ESD and FTR group was 30 mm in both. Hospitalization duration and TEM duration were statistically comparable in TEM ESD and FTR groups with p=0.52 and 0.70 respectively. For complications, in TEM ESD there were complications in 14% (n=12) subjects and 36.7% (n=40) from FTR which was significantly higher in the FTR group with p=0.01. Early complications (<30 days) were seen in 9.3% (n=8) and 25% (n=28) subjects from TEM ESD and FTR groups and late (>30 days) in 4.7% (n=4) and 10.7% (n=12) subjects respectively from TEM ESD and FTR groups (Table 3).

It was seen that for histopathological characteristics of carcinoma, Tumor budding was seen in 41% (n=14) subjects and perineural invasion in 6% (n=2) subjects, G-histopathological grading of G2 and G3 in 76% (n=26) and 6% (n=2) subjects respectively. Lymphtic invasion was seen in 12% (n=4) of study subjects. The venous invasion was seen in 18% (n=6) and Vx-venous invasion couldn’t be assessed in 6% (n=2) subjects respectively. Microscopic and macroscopic residual tumor was seen in 35% (n=12) and 6% (n=2) subjects respectively. T staging of T1, T2, and Tx was seen in 47% (n=16), 47% (n=16), and 6% (n=2) subjects respectively (Table 4).

Table 1: TEM data in study subjects

Table 2: Histopathological characteristics in study subjects

Table 3: TEM ESD (endoscopic submucosal dissection) and FTR in study subjects

Table 4: Histopathological characteristics of carcinoma

The present study assessed 224 subjects who underwent TEM at the Institute within the defined study period for spectroscopic microsurgical excision of pathological tissue in the rectum. The indications for TEM in study subjects were re-resection after polyp with adenocarcinoma, recurrence of benign polyp, primary polyp, and others in 10.7% (n=24), 11.6% (n=26), 75.9% (n=170), and 1.8% (n=4) subjects respectively. For resection type and radicality, TEM-assisted ESD, FTR, and other procedures were done in 39.3% (n=88), 58.9% (n=132), and 1.8% (n=4) subjects respectively. Macroscopically radical resection estimated by the surgeon was seen in 99.1% (n=222) of subjects. The mean distance from the anal verge was 14 cm, the mean polyp diameter was 30mm, the mean TEM duration was 60 minutes, and the mean hospitalization duration was 8.5 hours. These data were comparable to the studies of Tsai BM et al⁵ in 2010 and Laliberte AS et al⁶ in 2015 where authors reported comparable demographics in subjects undergoing TEM for rectal polyps as seen in the present study.

The study results showed that on assessing the histopathological characteristics in study subjects, micro radical resection was done in 160 subjects and not started in 8 subjects where recurrence was seen in 12 and 0 subjects respectively. In 56 subjects with no microradical resection, recurrence was seen in 2 subjects. The mean polyp diameter was 30 mm with the range of 6-133mm. The most common polyp type was tubular seen in 100 subjects followed by tubulovillus in 52, adenocarcinoma in 34, villous in 6, and serrated and others in 4 subjects with recurrence in 10, 4, 0, 0, 0, and 0 subjects respectively. These results were consistent with the studies of Yap K et al⁷ in 2017 and Whitehouse PA et al⁸ in 2006 where histopathological characteristics of post-TEM specimens similar to the present study were also reported by the authors in their studies.

It was seen that for TEM ESD (endoscopic submucosal dissection) and FTR in study subjects, the mean polyp diameter in TEM ESD and FTR group was 30 mm in both. Hospitalization duration and TEM duration were statistically comparable in TEM ESD and FTR groups with p=0.52 and 0.70 respectively. For complications, in TEM ESD there were complications in 14% (n=12) subjects and 36.7% (n=40) from FTR which was significantly higher in the FTR group with p=0.01. Early complications (<30 days) were seen in 9.3% (n=8) and 25% (n=28) subjects from TEM ESD and FTR groups and late (>30 days) in 4.7% (n=4) and 10.7% (n=12) subjects respectively from TEM ESD and FTR groups. These findings were in agreement with the results of Issa N et al⁹ in 2020 and Naughton AP et al¹⁰ in 2020 where results reported by the authors in their studies were comparable to the results of the present study.

The study results also showed that for histopathological characteristics of carcinoma, Tumor budding was seen in 41% (n=14) subjects and perineural invasion in 6% (n=2) subjects, G-histopathological grading of G2 and G3 in 76% (n=26) and 6% (n=2) subjects respectively. Lymphtic invasion was seen in 12% (n=4) of study subjects. The venous invasion was seen in 18% (n=6) and Vx-venous invasion couldn't be assessed in 6% (n=2) subjects respectively. Microscopic and macroscopic residual tumor was seen in 35% (n=12) and 6% (n=2) subjects respectively. T staging of T1, T2, and Tx was seen in 47% (n=16), 47% (n=16), and 6% (n=2) subjects respectively. These results were in line with the findings of McCloud JM et al¹¹ in 2006 and Ganai S et al¹² in 2006 where histopathological characteristics of carcinoma similar to the present study were also reported by the authors in their respective studies.

The present study, considering its limitations concludes that TEM is an efficacious and secure method for the removal of rectum polyps concerning both complications and recurrence rates. A low recurrence rate and fewer complications are seen following TEM for polyp removal. It demands the need for early checkups irrespective of the status of the resected margins. Also, TEM quality is ensured by no recurrence case had cancer.

1. Amann M, Modabber A, Burghardt J, Stratz C, Falch C, Buess GF, et al. Transanal endoscopic microsurgery in the treatment of rectal adenomas and T1 low-risk carcinomas. World J Surg Oncol. 2012;10:255.
2. Demartines N, Von Flue MO, Harder FH. Transanal endoscopic microsurgical excision of rectal tumors: indications and results. World J Surg. 2001;25:870–5. 
3. Chan T, Karimuddin AA, Raval MJ, Phang PT, Tang V, Brown CJ, et al. Predictors of rectal adenoma recurrence following transanal endoscopic surgery: a retrospective cohort study. Surg Endosc. 2020;34:3398–407.
4. Winawer SJ. Natural History of Colorectal Cancer. Am J Med. 1999;106(1A):3S-6S. 
5. Tsai BM, Finne CO, Nordenstam JF, Christoforidis D, Madoff RD, Mellgren A, et al. Transanal endoscopic microsurgery resection of rectal tumors: outcomes and recommendations. Dis Colon Rectum. 2010;53:16–23.
6. Laliberte AS, Lebrun A, Drolet S, Bouchard P, Bouchard A. Transanal endoscopic microsurgery as an outpatient procedure is feasible and safe. Surg Endosc. 2015;29:3454–9. 
7. Yap K, Mills S, Thomas M, Moore J. Submucosal dissection has advantages over full-thickness transanal endoscopic microsurgery in selected rectal lesions. ANZ J Surg. 2017;87:903–7. 
8. Whitehouse PA, Tilney HS, Armitage JN, Simson JNL. Transanal endoscopic microsurgery: risk factors for local recurrence of benign rectal adenomas. Colorectal Dis. 2006;8:795–9.
9. Issa N, Fenig Y, Schmilowitz-Weiss H, Khatib M, Bachar G, Gingold-Belfer R, et al. Simultaneous local excision of synchronous rectal polyps by transanal endoscopic microsurgery. Eur J Gastroenterol Hepatol. 2020:32:45–7.
10. Naughton AP, Ryan EJ, Bardon CT, Boland MR, Aherne TM, Kelly ME, et al. Endoscopic management versus transanal surgery for early primary or early locally recurrent rectal neoplasms-a systematic review and meta-analysis. Int J Colorectal Dis. 2020;35:2347–59.
11. McCloud JM, Waymont N, Pahwa N, Varghese P, Richards C, Jameson JS, et al. Factors predicting early recurrence after transanal endoscopic microsurgery excision for rectal adenoma. Colorectal Dis. 2006;8:581–5. 
12. Ganai S, Kanumuri P, Rao RS, Alexander AI. Local recurrence after transanal endoscopic microsurgery for rectal polyps and early cancers. Ann Surg Oncol. 2006;13:547–56.