Endoscopic resection of

ｌaterally spreading tumours (LSTs)

in the colon and rectum

Kazuhiro Watanabe, MD, Chizu Yokoi, MD,

Hideaki Yano, MD, FRCS

Department of Gastroenterology

National Center for Global Health and Medicine

COI

Nothing to disclose

Background

Laterally spreading tumours (LSTs) are superficially

spreading neoplasms greater than 10 mm in diameter.

LSTs are likely to be adenomas or early-stage cancers,

which are predicted by their morphological features.

Most LSTs are best treated

by local excision.

LSTs subtype

LST-Granular (LST-G)

LST-Nongranular (LST-NG)

sm sm

Submucosal invasion: 19/287 (7%)

sm

Submucosal invasion: 32/224 (14%)

sm

Uraoka T, Saito Y, et al. Gut 2006

Background

Surgery is usually recommended for large colorectal

tumours. However, in Japan, endoscopic resection is

the preferred approach for LSTs, especially in the rectum.

Little is known about the differences between rectal

and colonic LSTs.

Aim

To compare rectal and colonic LSTs with regards to:

1. Subtype and clinicopathological features

2. Safety and outcome of endoscopic resection

Patients and Methods

A single institution, retrospective study

Between August 2010 and September 2013

160 patients, with 175 cases of endoscopically removed LSTs

Clinical and clinicopathological outcomes were evaluated

Categorical variables were evaluated by χ2 test

Continuous variables were evaluated by t-test or Mann-Whitney test

Current strategy for LSTs

Treatment

EMR

(Endosoopic

Mucosal Resection)

ESD(Endoscopic

Submucosal Dissection)

surgery

Endoscopic diagnosis

<20mm

>20mm

SM deep invasive

cancer

LST-G

LST-NG

LST

(in Japan)

EMR techniques

Conventional EMR

EPMR (Endoscopic piecemeal mucosal resection)

ESD techniques

Patient demographics and procedures

Table1

TotalColonic

LSTs

Rectal

LSTsP-value

N 175 152 23

Median Age (years) 70.6 70.9 68.4 0.85

Gender (M/F) 100/60 87/50 13/10 0.50

Procedures

ESD 48 37 (24%) 11 (48%)

EMR 127 115 (76%) 12 (52%)

conventional EMR 76 70 6

EPMR 49 44 5

ESD+EMR 2 1 1

Morphologic features and size

89 (59%) 63 (41%) 19 (83%) 4 (17%) P<0.05

21mm < 32mm P<0.05

Colon (n=152) Rectum (n=23)

LST-G LST-NG LST-NGLST-G

Pathological outcome

table2

Colonic

LSTs

Rectal

LSTsP-value

N 152 23

Adenoma 95 (63%) 15 (65%) 0.91

Cancer 56 (37%) 8 (35%) 0.89

Sm-invasive cancer 9 (6%) 3 (13%) 0.25

sm-minute ca 6 2 0.34

sm-deep ca 3 1 0.49

lymphovascular invasion 1 0 0.70

sm-minute ca: submucosal invasive cancer less than 1mm below the muscularis mucosae

sm-deep ca: submucosal deep invasive cancer

Pathological outcome for each subtype

table3

Colon Rectum P-value

LST-G (n) 89 19

Adenoma 61 (69%) 12 (63%) 0.84

Cancer 28 (31%) 7 (37%) 0.65

Sm ca 3 (3%) 2 (11%) 0.20

LST-NG (n) 63 4

Adenoma 34 (54%) 3 (75%) 0.68

Hyperplasia 1 0

Cancer 28 (44%) 1 (25%) 0.45

Sm ca 6 (10%) 1 (25%) 0.40

Sm ca: submucosal invasive cancer

Outcome and adverse event of ESD

Table4

Colonic

LSTs (37)

Rectal

LSTs(11)

P-value

En-bloc resection rate 35 (95%) 10 (91%) 0.94

Local recurrence 0 0

Procedure time (min) 99 96 0.69

Major complications 0 0

Minor complications

Post operative bleeding 2 (5%) 3 (27%) 0.07

Minor perforation 5 (14%) 0 0.23

Outcome and adverse event of EMR

Table5

Colonic

LSTs (114)

Rectal

LSTs (11)

P-value

En-bloc resection rate 70 (61%) 6 (55%) 0.82

Local recurrence 4 (4%) 0 0.54

Major complications 0 0

Minor complications

Post operative bleeding 0 0

Minor perforation 1 0 0.76

Complications

Perforation

Bleeding

Summary

Rectal LSTs were more likely to be granular (LST-G) and

significantly larger than colonic LSTs.

Endoscopic resection for LSTs has a good outcome, but

perforation rate is slightly higher in colon.

Conclusion

Endoscopic resection of LSTs is a safe and effective

treatment despite their larger size and can be a viable

alternative to surgery in the majority of patients.