Τransanal Minimally Invasive Surgery-TAMIS and transanal endoscopic microsurgery-TEM are innovative techniques used for the removal of large polyps or early stage malignant tumors that cannot be removed with conventional colonoscopy. The procedure is performed through the anus, without incisions. The tumor is removed with the use of laparoscopic equipment and a special port is inserted transanally.
The TEM method (1980) and the TAMIS method (2009) are similar and rely on the same principles. They aim at removing benign polyps and early tumors without applying conventional open and laparoscopy surgery procedures. Indications and advantages are similar and are cited below: Their main difference is that in TEM a reusable and re-sterilisable port is used while TAMIS is performed using conventional laparoscopic tools and a camera.
Indications:
- Large sessile rectal dysplastic polyps
- Rectal carcinoma at stage Τ1Ν0Μ0 well or moderately differentiated.
- Size of tumor up to 4 cm and 40% of its circumference
- Absence of lymph nodes in the MRI – lymph node infiltration
- Distance between the tumor and the anus measuring between 4cm and 20cm in length
The application of TEM-TAMIS is also acceptable as palliative treatment in more advanced rectal cancers in the presence of comorbidities that render the patient non eligible for radical surgery.
It is worth noting that not all patients are eligible for this surgical procedure since there are specific contraindications. Most of those patients are treated with laparoscopic surgery of the colon. The contraindications for this surgical procedure are as follows.
Contraindications:
- Positive lymph nodes
- Remote metastasis
- Tumor ulceration
- Large tumor extending to muscularis propia
- Low differentiation tumors
- Lymph node infiltration
Both TAMIS and TEM are two rapidly evolving methods globally because they offer significant advantages such as:
- Invisible incisions
- Less post operative pain
- Less loss of blood
- Faster recovery
- Shorter hospital stay (even same day discharge)
- Avoidance of colostomy (artificial anus) placement
The first results obtained from large multi-centre studies are encouraging since they reflect the above advantages and indicate that this is a safe and reproducible method, while the oncologic results are comparable to the conventional methods. They require, however, a large learning curve, adequate surgeon’s training together with accurate application of indications.