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Erkan et al. Mini-invasive Surg 2018;2:30 I http://dx.doi.org/10.20517/2574-1225.2018.51 Page 3 of 10

The need for an oncologically safe and also cost effective procedure led to evolution of TAMIS. TAMIS uti-
lizes conventional laparoscopic devices and a single incision port rather than a specialized platform. There-
fore, it lowers the cost of the procedure, while giving the surgeon an opportunity to operate with familiar
instruments. It also allows for a 360° exposure of the rectal lumen, which is another superiority over TEM.
While TEM requires repositioning of the patient or the platform, TAMIS allows operating in multiple
quadrants using the same configuration. First described in 2010, TAMIS was found to be a feasible alterna-
tive to TEM, providing its benefits at a fraction of the cost without specialized instrumentation [1,3,17-19] .

AN INDIVIDUALIZED APPROACH FOR PATIENTS
Patients with rectal cancer being considered for local excision, should undergo routine staging workup
like any other rectal cancer patient, including dedicated magnetic resonance imaging of rectum for local
staging, computed tomography of chest, abdomen and pelvis to screen for distant metastases and baseline
carcinoembryonic antigen level to guide future follow-up and treatment.

Neoadjuvant treatment followed by TME is still considered the gold standard treatment for locally invasive
rectal cancer in terms of oncological outcomes. However, it also has significant effects on patients’ quality
of life. The Dutch Colorectal Cancer Group reported 14% fecal incontinence, 52% bowel dysfunction and
[20]
57% urinary incontinence at 5-year follow-up . These relatively high morbidity rates have strengthened
the search for alternative treatment options providing a balance of favourable functional outcomes without
compromising oncological results.

[2]
The uptake of colorectal cancer screening has enabled more patients to be diagnosed at an early stage . We
have also more knowledge about tumor biology and risk factors for aggressive behaviour of the disease. All
of these together, bring up the potential for less radical organ preserving surgery in an effort to improve
patients’ quality of life. One concern for local excision is excessive tissue removal leading to a narrowed
lumen and rectal stenosis. However, we know from TEM literature that stenosis following TEM excision
[21]
is rare unless the lesion is circumferential. Recently, McLemore et al. reported a single case of rectal ste-
nosis in a cohort of 32 patients who underwent TAMIS for both benign and malignant rectal tumors. The
patient who developed stenosis had a large circumferential adenoma and was subsequently managed suc-
cessfully with endoscopic dilation.

T1N0
[23]
[22]
Early rectal cancer is defined as cancer confined to submucosa . Kikuchi et al. further classified early
rectal cancer according to depth of invasion of the tumor by dividing submucosal layer into thirds. While
the risk of lymph node metastasis is 3% for lesions invading the superficial 1/3 of submucosa (SM1), it rises
up to 8% for middle (SM2) and to 23% for deeply invading lesions (SM3) [24-26] .

The 2013 American Society of Colon and Rectal Surgeons practice parameters for the management of rec-
tal cancer state that local excision is an appropriate treatment modality for carefully selected T1 rectal can-
[27]
cers without high-risk features .

Favourable T1 lesions have a less than 10% risk of lymph node metastasis and local excision can be poten-
[2]
tially curable for these patients [Figures 1-3]. The Swedish Rectal Cancer Registry analysis demonstrated
that the rate of lymph node metastasis is 6% in the absence of adverse features (lymphovascular invasion or
poor differentiation).

A recent analysis of Surveillance, Epidemiology, and End Results database, showed that local excision of T1
rectal cancer does not affect cancer-specific survival when compared to radical surgery. However, less radi-
[28]
cal approach comes at a cost of need for more frequent and careful follow-ups .