Which lesions are suitable for TAMIS surgery?

TAMIS removes certain lesions in the rectum using a camera and instruments inserted through the anus. The name stands for transanal minimally invasive surgery: transanal means through the anus, and minimally invasive describes an approach that involves more limited intervention in the tissues. In a suitably selected case, the lesion can be removed without an abdominal incision.

This technique is considered particularly for some large benign polyps and selected early cancers. However, a limited procedure is not enough for every condition. Because TAMIS does not remove the lymph nodes around the bowel, cancer with a risk of spread to these nodes may require more extensive surgery.

A polyp's structure matters as well as its size

A polyp is a growth of tissue projecting from the inner surface of the bowel. Many polyps are benign, but some may develop cancerous changes over time. A large polyp is not necessarily cancerous; a small one does not rule out all risks either.

A colonoscopy is a camera examination of the inside of the colon and rectum. Many polyps can be removed during this examination. If a lesion has a broad base, is in a difficult position or has grown back in a scar after previous removal, another technique may be needed. TAMIS is one possible option in this situation.

Before a decision is made, the polyp's location, extent and tissue sample results are reviewed. If needed, magnetic resonance imaging, or MRI, of the pelvis and an ultrasound examination from inside the rectum are performed. These help assess how deeply the lesion has grown into the bowel wall and the nearby lymph nodes. Lymph nodes are structures in the immune system to which cancer cells can spread.

A previous biopsy, an examination of a small tissue sample, may provide information about only part of the lesion. Even if the initial result is benign, further changes may therefore be found when the whole lesion is removed. The full laboratory report determines the subsequent surgical plan.

Early cancer and neuroendocrine tumours

TAMIS may be suitable for some low-risk T1 cancers. T1 means that the tumour has grown into the layer beneath the bowel's inner lining but has not reached the muscle layer. This designation alone is not enough to choose the procedure: cell characteristics, depth of invasion and the likelihood of spread to lymph nodes are also assessed.

For tumours that have grown into deeper layers, or when lymph nodes are suspicious, local removal does not usually replace the main surgical treatment. Special cases in which major surgery is unsuitable are discussed separately at a multidisciplinary team meeting. Alongside the patient's general condition, the risks that remain with more limited treatment must be discussed openly.

Neuroendocrine tumours develop from specialised cells in the bowel associated with hormone signalling. Some grow slowly, while others behave more aggressively. TAMIS may be used for selected, localised rectal neuroendocrine tumours, but size, depth, the rate of cell multiplication and spread are considered together. For some small tumours, other methods of local removal using a camera are sufficient.

A specific example of this operation is shown in the video TAMIS for a rectal carcinoid tumour. This is surgical footage intended for adults. “Carcinoid”, used in the video, is a name that has been used for this group of tumours; the detailed tissue report provides the key information for treatment decisions.

What happens on the day of surgery?

TAMIS: Transanal Minimally Invasive Surgery is usually performed under general anaesthesia, with the patient asleep. A special access device is placed in the anal canal, and the camera and surgical instruments pass through it. The surgeon dissects the lesion under direct vision, together with an appropriate margin of healthy tissue around it.

If needed, a small section containing all layers of the bowel wall is removed. The aim is to remove the tissue as intact as possible so that its depth and edges can be assessed in the laboratory. Whether the resulting defect is stitched closed depends on its location and the details of the operation.

The hospital provides preparation instructions. Bowel cleansing, when to stop eating and drinking, and the plan for blood-thinning and diabetes medications are clarified beforehand. Do not stop medications on your own. The team also needs to know about allergies and any previous problems with anaesthesia.

If the procedure cannot be completed safely through the anus, a different surgical approach may be needed. This possibility is explained during the consent discussion before surgery. A stoma, an opening of the bowel onto the abdominal wall, is not usually created during TAMIS; this may change if more extensive surgery is needed.

Early recovery and warning signs

The length of the hospital stay depends on the extent of the procedure and your general condition. At discharge, you are given individual advice on pain relief, diet and bowel function. At first, you may have discomfort around the anus, a little blood spotting and mucus discharge. Symptoms that increase rather than settle need assessment.

Stretching the anal canal during surgery may cause temporary leakage of wind or stool. A diet plan and, if necessary, stool softeners are agreed with your doctor to prevent constipation and straining. Using enemas or inserting medication into the anus on your own may not be appropriate for the healing area.

Walking is resumed gradually, and the timing of heavy physical work is discussed with the surgeon. Fever, increasing abdominal or anal pain, persistent vomiting, inability to pass urine and heavy bleeding require urgent medical assessment. Having contact details in your discharge paperwork helps avoid delays in these situations.

When do laboratory results change the need for further surgery?

The pathologist examining the tissue determines the lesion's type, depth and cut margins. If cancer cells reach the edge, there is deeper invasion or there are signs of spread into lymphatic or blood vessels, TAMIS alone may not be enough. In this situation, a more extensive operation to remove the bowel together with the surrounding lymph nodes is discussed.

A recommendation for further surgery does not mean that the first procedure was pointless: the complete tissue sample may reveal a previously unknown risk. Even when follow-up alone is chosen, repeat camera examinations and any necessary imaging are scheduled. A benign result does not automatically remove the need for further bowel examinations.