Indications for TEM: Tissue-free, broad-based benign rectal adenomas with a maximum diameter of more than 1.5 cm (stage T0), especially villous adenomas, are most suitable for TEM treatment. The design of the special instrumentation of TEM allows the removal of rectal tumors located at any distance between 5 and 20 cm from the anal verge. For rectal carcinoma in situ (Tis stage) or stage T1 rectal carcinoma with low risk of recurrence (e.g., tumor is highly or moderately differentiated, small and active), TEM offers a high chance of cure. Although, rectal cancers with high risk of recurrence at stage T1 or more advanced (e.g., stage T2 or above) have a high chance of recurrence after local resection, TEM still provides an ideal palliative treatment for those patients with high surgical risk, such as those of advanced age or with severe comorbidities. Other indications for TEM: rectal carcinoid tumors, mesenchymal tumors, rectal strictures and even rectovaginal fistulas are ongoing clinical trials of TEM combined with adjuvant radiotherapy for pT2 rectal cancer. Contraindications to TEM: TEM is not indicated for stage T1 rectal cancer with high risk of recurrence or more advanced (e.g., stage T2 or higher) rectal cancer that is not for palliative treatment; simultaneous multiple primary colorectal tumors are contraindications to TEM and should be ruled out by preoperative total colonoscopy, barium enema angiography, or multi-row CT colorectal reconstruction. TEM may affect the anal sphincter to a certain extent, because a special rectoscope with an external diameter of 4 cm must be inserted through the anus until the end of the operation. Therefore, TEM should not be performed in patients with poor anal sphincter function to avoid postoperative anal incontinence. The surgical method of TEM: general anesthesia (or intralesional anesthesia), selection of the appropriate surgical position according to the location of the tumor, the principle is to make the tumor located as far as possible in the lower right side of the visual field after the insertion of the proctoscope (if the tumor is located at 3, 6, 9 and 12 o’clock in the knee-thorax position, the right lateral, prone, left lateral and bladder truncal positions will be used, respectively). The rectoscope will be inserted through the anus and adjusted in position to maintain CO2 inflation at a maximum rate of 6 L/min. The CO2 pressure in the rectal lumen can be automatically adjusted to maintain between 12-15 mmHg to prevent overdistension of the colon. Under the stereoscopic and lumpectomy system, a 1:200,000 epinephrine solution is first injected at the base of the tumor to reduce bleeding and elevate the mucosa. The resection border (approximately 1 cm from the tumor margin) is first marked by electrocautery with a needle electrodebrider. Precise excision along the predetermined marker line ensures complete resection of the tumor at the appropriate margin. For non-cancerous choriocapillaris adenomas (stage T0), we prefer to perform submucosal resection. If preoperative biopsy indicates malignancy, but rectal ultrasonography shows no invasion of the submucosa (Tis or T1 stage), total resection is performed with the ultrasonic knife. The integrity of the specimen is ensured and a 1 cm margin is available. The excised tumor specimen was spreading around the periphery and fixed on a small piece of polyethylene foam with multiple large-headed pins, which was treated with formalin solution and immediately sent for pathological staging. The surgical wound is closed intracavernally: first, a 7-10 cm long monofilament absorbable suture with stitches is fixed with a silver clip at the end outside the body and sent into the rectal cavity through a special proctoscope, and the intracavernous suture is performed with special forceps and needle-holding forceps starting from one end of the wound. If the incision is large or difficult to close, multiple sutures can be used to close it in stages. Superiority of TEM: TEM provides a safe and effective method of treating benign rectal adenomas and early rectal cancer. This minimally invasive surgical approach combines the advantages of endoscopic, laparoscopic and microsurgery, has a lower complication rate and shorter postoperative hospital stay, and minimizes the need for an enterostomy.