Transanal minimally invasive surgery (TAMIS)

During TAMIS, a small specialised platform is placed gently into the anal canal. Through this platform, tiny laparoscopic instruments and a magnified camera are introduced, allowing the operator to see and work inside the rectum with great precision — more clearly than would be possible with the naked eye. The tumour or polyp (a growth in the lining of the rectum) is then carefully cut out, and the defect (the gap left behind) is sewn closed.

TAMIS is suitable for benign polyps that are too large or awkwardly positioned to be removed by colonoscopy, and for early rectal cancers — particularly stage T1 (where cancer is limited to the inner layers of the bowel wall). In carefully selected patients with a T2 cancer who cannot safely undergo major abdominal surgery, TAMIS may also be an option.

If you have heard the older term TEM or TEMS (Transanal Endoscopic Microsurgery), TAMIS is the modern evolution of that operation — it uses the same principle (working entirely through the anus) but with more flexible instruments and a wider range of access.

TAMIS sits in the middle of the three main options for a rectal polyp or early cancer — between a simple endoscopic removal and a major abdominal resection. Which one is right for you depends on the size, depth, and features of the lesion, and is decided at MDT.

• You have an early rectal cancer (T1 or selected T2) and a bowel-preserving approach is being considered
• You have a large adenoma (a precancerous growth) in the rectum that cannot safely be removed during a colonoscopy
• A polyp has grown back or was not fully removed after previous endoscopic treatment
• You have a carcinoid tumour (a rare slow-growing neuroendocrine tumour) in the rectum
• A lesion is on the side or back wall of the rectum where a standard camera cannot easily reach
• Radical resection is felt to carry too much risk given your medical fitness, and TAMIS offers a less invasive alternative — a decision taken at MDT

For rectal cancer, the decision to do TAMIS rather than a radical resection is taken at a multidisciplinary team (MDT) meeting — where surgeons, medical oncologists, radiation oncologists, radiologists, and pathologists review your case together. The MDT looks for features that make TAMIS appropriate: a low-risk T1 cancer (limited to the inner bowel-wall layers), well-differentiated histology, no lymphovascular invasion, and a lesion in a position TAMIS can safely reach. Selected T2 cases in patients unsuited to major surgery are also discussed individually.

Suitability is determined with MRI of the pelvis (and sometimes endorectal ultrasound) to map the depth and extent of the lesion before a final plan is made.

TAMIS also fits within the broader spectrum of organ preservation. For some patients with rectal cancer who have a complete clinical response after chemoradiotherapy, surgery can sometimes be avoided altogether in favour of close surveillance — known as a Watch & Wait approach. Whether this is relevant for your situation can be discussed at consultation; it is always an MDT-led decision.

• No cuts on your abdomen — recovery is faster and wound complications are less likely
• Your rectum and bowel function are preserved — most patients do not need a stoma
• The magnified camera view gives clearer visibility inside the rectum than working from the outside through the abdomen
• The tumour is removed in full thickness (including the deeper muscle layer) which means the pathologist can check every margin accurately and give you a precise staging
• Most patients go home after 1–2 nights — a shorter stay than major bowel surgery
• Your bowel continues to function normally after the procedure

• Incomplete margins — in around 10–15% of early cancers, the pathologist finds that the tumour was closer to the edge of the removed tissue than ideal. If this happens, whether further surgery or radiotherapy is needed will be discussed with you. This is not a failure — it is the pathology system working exactly as it should to protect you.
• Perforation into the abdomen — happens in fewer than 1% of cases. If it occurs, it is usually recognised immediately and repaired during the same operation without complications.
• Post-operative bleeding — affects 1–3% of patients; usually settles on its own or is managed with a small procedure
• Tenesmus and urgency — a feeling of needing to go to the toilet frequently, or a constant sensation of pressure in the back passage, is very common in the first 2–4 weeks after surgery. It settles on its own as the rectum heals.
• Local recurrence — TAMIS preserves the rectum, and this trade-off comes with a small risk that cancer can come back locally. For low-risk T1 cancers, local recurrence rates are around 5–10%. For T2 cancers, the rate is higher than with radical surgery, which is why TAMIS for T2 is reserved for selected cases discussed at MDT. This is the principal reason that surveillance after TAMIS is intentionally intensive — see below.
• Anaesthetic risks — as with any operation requiring general anaesthetic

If you take blood thinners, diabetes medication, GLP-1 weight-loss injectables, or iron supplements, please flag this when you book — these need specific adjustments before the procedure. Full details are in the guides above.

• You will receive antibiotics around the time of surgery to reduce the risk of infection
• Before you sign consent, there will be a thorough conversation about what the procedure involves, what the pathology results might show, and what further treatment might be needed depending on what is found

• You will be admitted to Warringal Private Hospital or Epworth Eastern on the morning of your surgery
• A general anaesthetic is given so you are fully asleep throughout
• You are positioned carefully on the operating table (either on your back with your legs raised, or face down depending on where the lesion is) to give the best possible access to the lesion
• The TAMIS platform is gently inserted through the anus; laparoscopic instruments are then introduced through it
• The lesion is excised under magnified camera vision; the gap left behind is sewn closed with dissolvable stitches
• You wake up in the recovery room; a urinary catheter may be in place and is usually removed the same day
• Sips of water and a light diet are started on the day of surgery itself

• Day 0–1: Liquids and light food; you are helped to get up and move around as soon as you feel ready
• Days 1–2: Most patients are well enough to go home with oral pain relief — usually simple paracetamol and anti-inflammatory tablets
• Week 1: Rest and soft foods at home; avoid anything strenuous while the repair inside the rectum settles. Some urgency or frequent toilet trips is normal during this time.
• Week 4: You should be back to your normal activities by this point
• Once pathology results are back (usually within 1–2 weeks), they will be gone through with you in detail. If further treatment is recommended, you will have a clear explanation of why and what it involves — you will not receive news like this without support.
• Ongoing surveillance after TAMIS for cancer is intentionally more intensive than standard post-resection surveillance — typically 3-monthly clinical reviews, endoscopy, and MRI surveillance in the first two years, then less frequently thereafter. This is the price of organ preservation, and it is exactly how local recurrences are caught early enough to act on. This surveillance is coordinated with you, and the Bowel Cancer Follow-up and Surveillance guide gives an overview. For benign polyps, surveillance is less intensive but still important.
• A post-operative review is routinely arranged 2–6 weeks following your procedure, with timing depending on the type of operation — this review is provided at no charge

Post-operative concerns: Please call our rooms on (03) 9816 3951 and leave a message — this will be sent directly as a text to Mr Nguyen. Alternatively, you may text the office mobile on 0499 090 126. We aim to respond promptly during business hours.

Emergencies: For any life-threatening emergency, call 000 immediately or go to your nearest emergency department. Do not wait for a call back from our rooms. For the Austin Hospital Emergency Department: (03) 9496 5000.