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Page 2 of 9 Adegbola et al. Mini-invasive Surg 2018;2:40 I http://dx.doi.org/10.20517/2574-1225.2018.55

[2]
ized equipment . The benefit over TEM was mostly in overcoming the steep learning curve and associated
expense. Other reported benefits favouring TAMIS include rapid set-up time, 360 degrees vs. 220 degrees
of visibility within the rectal lumen, the adaptability to available laparoscopic instruments, and the ease of
[2-4]
patient and equipment positioning within the operating theatre . Furthermore, it is hypothesised that the
soft transanal access platform with TAMIS offers less sphincter traction, although this has not been con-
[4]
clusively demonstrated to translate to better functional outcome postoperatively .
The evolution of TAMIS has seen a rapid progression into a technique that is now an established practice
of some colorectal surgeons globally and has seen some of the cutting-edge developments in surgical inno-
[5,6]
vation in colorectal surgery . Since the inception of TAMIS, several changes have been made to optimize
the technique and broaden indications, reflecting the stages described by the IDEAL (“Idea, Development,
[7-9]
Exploration, Assessment, Long-term study”) framework for surgical innovation . The ease of access to
the rectum and pelvis that is provided by TAMIS allows it to be used for various additional applications.
In this article, we discuss the widening applications and latest developments in TAMIS use, which signpost
the future direction with this new platform.

EARLY APPLICATION
Local excision of rectal neoplasia
Initially TAMIS was used largely for local excision of rectal lesions within the context of benign (e.g., ad-
enomatous polyps unsuitable for endoscopic resection) or early-stage (T1) malignant tumours with a low
risk for lymphatic involvement at the time of operation or local excision as a form of palliation in patients
(T3 and above) who are medically unfit or unwilling to go ahead with standard oncologic surgery [10-13] .
Studies report similar advantages conferred with TAMIS as for TEM when compared with conventional
transanal resection, with more intact, non-fragmented specimens, negative resection margins and lower
recurrence rates [6,12] . For very distal lesions or those at or just above the dentate line, a hybrid approach
with standard transanal and TAMIS equipment can facilitate resection [12,14] . TAMIS has also been consid-
ered in local excision of tumour site in patients with locally advanced rectal cancer following neoadjuvant
[15]
therapy; for the purpose of confirming mural complete pathologic response . This approach is considered
acceptable in certain scenarios in view of the low risk of occult node positivity for ypT0 lesions is low, at
3%-6% [12,16-19] . There is limited data evaluating the effectiveness of TAMIS for resection of neuroendocrine
(e.g., carcinoid tumours) however, small series suggest it is feasible for excision of small primary rectal
[10]
carcinoids, or following incomplete endoscopic removal [15,20] . A systematic review in 2014 reported on
a combined 390 TAMIS procedures for local excision of rectal neoplasia with publications from 16 coun-
tries. They reported an average excised lesion size of 3.1 cm (range 0.8-4.75 cm) with an average distance
of 7.6 cm from the anal verge (range 3-15 cm). Of the 390 TAMIS procedures included, 152 lesions were
benign (adenomas and high-grade dysplasias) 209 were malignant (carcinomas in situ/adenocarcinomas),
23 (0.05%) were for neuroendocrine lesions (e.g., carcinoid), three were for fibrosis (e.g., benign scar), one
[10]
mucocele, one gastrointestinal stromal tumour, and one melanoma . Within the series there were 29/390
complications (7.4%), the most common of which was self-limiting bleeding (10/29). Only five cases (1.28%)
were graded on the Clavien Dindo classification as grade 3 (one case of bleeding requiring reintervention
and four cases of inadvertent peritoneal entry) and no complications were graded higher. The conversion
rate was 2.31% (n = 9) necessitating either a transanal excision with a Park’s retractor, TEM surgery or
laparoscopy. The recurrence rate was low at 2.7% (7/259), albeit with only short term follow-up, with mean
duration of follow-up of approximately seven months. The concept of local excision for rectal cancer is of
course a hotly debated topic with both strong proponents and opponents. The role of radiotherapy followed
by local excision for early rectal cancers is an emerging field and has the potential for a complete re-evalua-
tion of current standards in rectal cancer surgery with a larger emphasis on organ preservation. A phase-II
study enrolled 63 patients with T3 or low-lying T2 rectal cancer who received local excision after achiev-
[21]
ing complete response to neoadjuvant chemoradiation . They found excellent cumulative 3-year overall