Transanal Endoscopic Microsurgery (TEM): Procedure, Recovery, Risks and Who It's For
Updated: 6 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026 · How we review
Quick Answer: What is transanal endoscopic microsurgery (TEM)?
Transanal endoscopic microsurgery (TEM) is a minimally invasive procedure that removes rectal tumors, polyps and other rectal problems using microsurgical tools passed through the anus, with no abdominal incision. It is done under general anesthesia, usually needs a one- to two-day hospital stay, and carries fewer complications and less pain than open surgery. [1]
What the research says
TEM removes large rectal lesions in one piece in nearly 99% of cases. A review of 21 case series (2,077 patients) found TEM achieved one-piece (en bloc) removal in 98.7% of patients and clear margins in 88.5%, compared with 87.8% and 74.6% for endoscopic submucosal dissection. Only 1.8% of TEM patients later needed abdominal surgery, versus 8.4%. (Arezzo et al., Surgical Endoscopy, 2014) [5]
Compared with radical surgery, TEM means fewer complications and stomas, but more local recurrence. A meta-analysis of 13 studies (5 randomized trials and 8 cohort studies) in early-stage rectal cancer found TEM lowered postoperative complications (RR 0.35) and permanent stomas (RR 0.16) and shortened the hospital stay by about 8.8 days, while local recurrence was higher (RR 2.51). (Li et al., International Journal of Colorectal Disease, 2023) [6]
Results depend strongly on tumor stage. A 2025 meta-analysis of 33 studies reported an overall recurrence rate of 7% and a complication rate of 11% after TEM, with 77.7% of complications classed as minor (grade I). Recurrence was 8.1% for T1 cancers but 19.7% for T2, so TEM alone is not recommended as curative treatment for T2 tumors. (Wang et al., Frontiers in Oncology, 2025) [7]
Key takeaways
TEM reaches tumors high in the rectum through the anus, so there is no belly incision. [1]
It treats benign rectal tumors, polyps, early rectal cancer, fistulas, strictures and rectal prolapse. [1][2]
Preparation is similar to a colonoscopy: clear liquids, a laxative bowel prep and nothing by mouth from midnight. [1]
Most people walk the same day, eat within a day and go home after one to two days. [1]
Loose bowel movements can continue for several weeks while the rectum heals. [1]
Some people with rectal cancer still need chemotherapy or radiation therapy after TEM. [1]
TEM at a glance
Feature | What to expect |
Access route | Through the anus, using a rigid tube called a rectoscope |
Abdominal incision | None |
Anesthesia | General anesthesia (sleeplike state) |
Closing the wound | Dissolvable stitches or metal clips inside the rectum |
Getting up | The same day as surgery |
Eating and drinking | Usually within a day |
Hospital stay | One to two days |
Back to usual activities | Usually within a day or two of going home |
What is transanal endoscopic microsurgery?
Transanal endoscopic microsurgery is a procedure that treats problems inside the rectum by passing small tools through the anus instead of cutting through the belly. [1] The rectum is the lower part of the large intestine, just above the anus.
Because the surgeon works from inside the bowel, there are no surgical incisions on the skin. This is why recovery is usually quicker and less painful than with open surgery. [1]
TEM also lets surgeons reach tumors high in the rectum. In the past, these tumors could only be reached with open abdominal surgery, which uses a large belly incision and can mean a long, painful recovery. [1]
What conditions does transanal endoscopic microsurgery treat?
Transanal endoscopic microsurgery is used most often to remove growths or tumors in the rectum. [1] It can also repair several other rectal problems. [1][2]
Condition | What it means |
Benign rectal tumors | Noncancerous growths in the rectum |
Rectal polyps | Small tissue growths on the rectal lining (see our guide to colon polyps) |
Early rectal cancer | Cancer found at an early stage in the rectum |
Rectal fistulas | Infected passageways in the rectum (learn more about fistulas) |
Rectal strictures | Narrowing of the rectum (compare with a colon stricture) |
Rectal prolapse | The rectum slipping out of its normal position (see rectal prolapse surgery) |
Who is a good candidate for transanal endoscopic microsurgery?
Transanal endoscopic microsurgery may be a good option for people who have several health conditions or who cannot tolerate open surgery. [1] It offers a way to remove colorectal cancer without open abdominal surgery.
TEM is also useful for younger people with early-stage or benign (noncancerous) rectal tumors. [1]
Who should not have transanal endoscopic microsurgery?
Not everyone is a candidate for TEM. [1] Because the rectoscope is rigid, the backbone can sometimes block the surgeon's path to the tumor. In these cases, a related technique called TAMIS, which uses more flexible tools, may be used instead.
People with a narrowing (stenosis) of the anal canal may not be candidates for either TEM or TAMIS. [1] Our guide to anal stenosis explains this condition in more detail.
What is the difference between TEM and TAMIS?
The main difference between TEM and transanal minimally invasive surgery (TAMIS) is the device placed in the anus. [1][4] TEM uses a rigid rectoscope, while TAMIS uses a soft, gel-like round port.
Feature | TEM | TAMIS |
Device in the anus | Rigid tube (rectoscope) | Small, gel-like round port |
Camera and tools | Small instruments and a camera passed through the rectoscope | The same camera and tools used in laparoscopic surgery, passed through the port |
Flexibility | Rigid; the backbone may block the path to some tumors | More flexible tools; an option when the rigid rectoscope cannot reach |
Abdominal incision | None | None |
How do you prepare for transanal endoscopic microsurgery?
Preparing for transanal endoscopic microsurgery is similar to preparing for a colonoscopy. [1] The bowel must be completely empty so the surgeon has a clear view of the rectum.
You will usually take a laxative to clear the colon and electrolytes to prevent dehydration. [1] Plan to stay at home during your bowel prep.
When | What your care team will likely ask |
Several days before | Stop certain medicines, such as blood thinners, if instructed |
One day before | Avoid solid foods |
12 to 24 hours before | Clear liquids only |
From midnight | Stop eating and drinking |
Many of the same tips apply as for colonoscopy, so our colonoscopy prep guide is a helpful companion read. Always follow the exact instructions from your own surgical team.
What happens during transanal endoscopic microsurgery?
During transanal endoscopic microsurgery, you receive general anesthesia, so you stay in a sleeplike state for the whole procedure. [1] The surgeon then follows five main steps: [1][3]
Inserts the rectoscope through the anus and into the rectum.
Fills the rectum with gas to get a clearer view of the tumor.
Places microsurgical instruments and a camera through the rectoscope.
Removes the tumor or polyp along with a small amount of surrounding tissue.
Closes the rectal lining with dissolvable stitches or metal clips, which the body reabsorbs or passes naturally as it heals.
What happens right after transanal endoscopic microsurgery?
Right after transanal endoscopic microsurgery, some discomfort is normal. [1] For the first 24 hours, you may have:
A thin tube (catheter) in the bladder to drain urine.
An intravenous (IV) line in a vein to give fluids.
IV antibiotics for 24 hours.
Most people can start eating and drinking within a day after surgery. The usual hospital stay is one to two days. [1]
How long is recovery after transanal endoscopic microsurgery?
Recovery after transanal endoscopic microsurgery is usually short. Most people get up and move around on the same day as the procedure, and return to their usual activities within a day or two of going home. [1]
Liquid bowel movements may continue for several weeks after TEM. If needed, a nutritionist or dietitian can help adjust your diet until bowel function returns to normal. [1]
What are the benefits of TEM compared with open surgery?
The main benefit of TEM is that surgeons can reach higher parts of the rectum without an abdominal incision. [1] Before TEM, these tumors needed extensive abdominal surgery, which can cause long-term side effects such as bladder problems, erectile dysfunction and a permanent colostomy.
Outcome | TEM | Open abdominal surgery |
Incision | None (through the anus) | Large belly incision |
Pain | Usually little pain | Can mean a long, painful recovery |
Bleeding | Less | More |
Infection and bowel obstruction risk | Lower | Higher |
Hospital stay | Shorter (one to two days) | Longer |
Recovery | Quicker | Slower |
Possible long-term effects | Fewer | Bladder problems, erectile dysfunction, permanent colostomy |
What are the risks of transanal endoscopic microsurgery?
Transanal endoscopic microsurgery has lower complication rates than open abdominal surgery, but a small risk of problems remains. [1] Possible complications include:
Bleeding.
Infection.
Rectal or abdominal pain.
Trouble emptying the bladder (urinary retention).
A sudden need to pass stool (fecal urgency).
Is transanal endoscopic microsurgery enough to treat rectal cancer?
Transanal endoscopic microsurgery is often enough for early-stage rectal cancer: for many people, it removes the tumor completely and no other treatment is needed. [1] However, some people also need chemotherapy or radiation therapy after TEM.
Your care team decides this based on the tumor's stage and what the removed tissue shows. Our in-depth guide to colon cancer staging and treatment explains how stage shapes treatment, and this patient summary of rectal cancer treatment covers local excision options by stage. [8]
When should you call a doctor after TEM?
Call your healthcare provider after transanal endoscopic microsurgery if you notice signs of a complication. [1]
Warning sign | What to do |
Bleeding from the rectum | Contact your surgical team |
Difficulty urinating | Contact your surgical team |
Fever or chills | Contact your surgical team |
Severe abdominal or rectal pain | Contact your surgical team promptly |
If bleeding is heavy or pain is severe and you cannot reach your team, seek emergency care.
Conclusion
Transanal endoscopic microsurgery gives people with rectal tumors, polyps and other rectal problems a way to avoid a large belly incision. The surgeon works through the anus, recovery is usually measured in days rather than weeks, and complication rates are lower than with open surgery. [1] For rectal cancer, TEM works best when the cancer is found early, and some people still need extra treatment afterward.
Next step: If you have been told you have a rectal polyp or tumor, ask a colorectal surgeon whether TEM or TAMIS is suitable for you. To learn more, read our guides to polypectomy, colon cancer and colonoscopy preparation.
FAQ
What is transanal endoscopic microsurgery?
Transanal endoscopic microsurgery (TEM) is a procedure that removes rectal tumors and treats other rectal problems using small tools inserted through the anus. There are no surgical incisions, so recovery is quicker and less painful than open surgery.
Is TEM surgery painful?
TEM is usually far less painful than open abdominal surgery because there is no belly incision. Some discomfort is normal right after the procedure, and it usually settles quickly.
How long does it take to recover from transanal endoscopic microsurgery?
Most people walk on the day of surgery, go home after one to two days and return to usual activities within a day or two. Loose bowel movements may continue for several weeks.
How do I prepare for TEM surgery?
TEM preparation is similar to colonoscopy prep. You avoid solid food for one day, drink only clear liquids for 12 to 24 hours, take a laxative bowel prep and stop eating and drinking at midnight before surgery.
What is the difference between TEM and TAMIS?
TEM uses a rigid rectoscope placed in the anus, while TAMIS uses a soft, gel-like port and standard laparoscopic tools. TAMIS can help when the rigid rectoscope cannot reach a tumor.
What are the risks of transanal endoscopic microsurgery?
TEM has lower complication rates than open abdominal surgery. Possible risks include bleeding, infection, rectal or abdominal pain, urinary retention and a sudden urge to pass stool.
Will I need chemotherapy or radiation after TEM for rectal cancer?
Many people with early-stage rectal cancer need no further treatment after TEM. Some people also need chemotherapy or radiation therapy, depending on the cancer's stage and the results of the removed tissue.
When should I call my doctor after TEM?
Call your healthcare provider if you have bleeding, difficulty urinating, fever or chills, or severe abdominal or rectal pain after TEM.
Will I need a colostomy after TEM?
No. TEM is done through the anus with no belly incision, and most people do not need a colostomy or stoma. If a larger operation is needed later, your surgeon will discuss the options.
Is bleeding normal after TEM?
Mild bleeding or a little blood with bowel movements can happen for a short time after TEM. Call your doctor if bleeding is heavy, you pass clots or you feel dizzy.
Related Reading
What Is Rectal Cancer? A Plain-Language Guide to the Signs, Causes, and Treatment explains rectal cancer, how it is diagnosed and treatment options.
Colon Polyps: Complete Guide to Symptoms, Causes, and Treatment covers polyps in the colon and rectum and why they are removed.
Polypectomy: Understanding the Procedure and Recovery describes how polyps are removed during a scope and recovery.
Low Anterior Resection (LAR): Rectal Cancer Surgery, Risks and Recovery explains the larger abdominal surgery used for some rectal tumors.
References
Cleveland Clinic. Transanal Endoscopic Microsurgery: Procedure & Recovery. Cleveland Clinic. Last updated May 3, 2023. https://my.clevelandclinic.org/health/treatments/17569-transanal-endoscopic-microsurgery-tems
Kunitake H, Abbas MA. Transanal endoscopic microsurgery for rectal tumors: a review. Perm J. 2012;16(2):45-50. PMID 22745615. https://doi.org/10.7812/tpp/11-120
Saclarides TJ. Transanal Endoscopic Microsurgery. Clin Colon Rectal Surg. 2015;28(3):165-175. PMID 26491409. https://doi.org/10.1055/s-0035-1562889
Stipa F, Tierno SM, Russo G, et al. Trans-anal minimally invasive surgery (TAMIS) versus trans-anal endoscopic microsurgery (TEM): a comparative case-control matched-pairs analysis. Surg Endosc. 2022;36(3):2081-2086. PMID 33844090. https://doi.org/10.1007/s00464-021-08494-y
Arezzo A, Passera R, Saito Y, et al. Systematic review and meta-analysis of endoscopic submucosal dissection versus transanal endoscopic microsurgery for large noninvasive rectal lesions. Surg Endosc. 2014;28(2):427-438. PMID 24149849. https://doi.org/10.1007/s00464-013-3238-3
Li W, Xiang XX, Da Wang H, et al. Transanal endoscopic microsurgery versus radical resection for early-stage rectal cancer: a systematic review and meta-analysis. Int J Colorectal Dis. 2023;38(1):49. PMID 36800079. https://doi.org/10.1007/s00384-023-04341-9
Wang C, Huang T, Wang X. Efficacy and safety of transanal endoscopic microsurgery for early rectal cancer: a meta-analysis. Front Oncol. 2025;15:1545547. PMID 39995839. https://doi.org/10.3389/fonc.2025.1545547
National Cancer Institute. Rectal Cancer Treatment (PDQ®)–Patient Version. National Cancer Institute. Last updated May 16, 2025. https://www.cancer.gov/types/colorectal/patient/rectal-treatment-pdq
Disclaimer
This article is for general education only and is not medical advice, a diagnosis or a treatment plan. Whether transanal endoscopic microsurgery is right for you depends on your diagnosis, tumor stage and overall health, so always follow the guidance of your own surgeon and care team. If you have heavy rectal bleeding, severe pain or a high fever after surgery, seek urgent medical care.
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