Roel Bogie

Endoscopic subtypes of colorectal laterally spreading tumors and risk of submucosal invasion: A meta-analysis

geographical region (studies from East Asian countries and Western studies) and starting year of inclusion was tested by adding these variables to the models mentioned before. A two-sided P value ≤0.05 was considered statistically significant. Results A total of 2949 unique articles were identified ( Figure 3.2 ). Based on title and abstract, we selected 197 articles for full text examination and included 48 studies in this meta-analysis. Of these, 19 were population based studies 19, 26-43 (1398 LST patients with 2663 LSTs) and 29 were lesion-based ( Figure 3.3 ). 1, 9, 17, 44-69 Twelve studies qualified as both population- and lesion-based studies. 19, 26, 30, 32-34, 36, 37, 39-41, 43 Table 3.1 shows an overview of the eligible studies used to calculate the pooled prevalence of LSTs and pooled risk of SMI. Two studies reported only the largest lesion per patient 26, 29 . Among the population-based studies, eight were Asian, 26, 27, 30, 32-34, 36, 38 eight were European 19, 29, 35, 37, 39, 41-43 and three were American studies. 28, 31, 40 In all studies, LST subtypes were classified using conventional chromoendoscopy (where specified). Five studies additionally used digital chromoendoscopy. 19, 31, 49, 50, 70

3

Eligible studies for prevalence estimates of LSTs

Eligible studies for risk of malignancy

12

29

7

Used in analysis of:

Prevalence of patients with LST(s) of all patients with colorectal neoplasm(s)

Prevalence of patients with ≥ 1 LST the study population

Endoscopic subtypes of LSTs

Location of LSTs

1

2

7

1

2

2

4

17

0

0

0

4

Prevalence of LSTs of all colorectal neoplasms

Histopathology of LSTs

10

10

Figure 3.3: Overview of the studies used for the various calculations. | Note: 31 studies (10+17+4) provided information about LST histology. Of these 31 studies, 26 were used for SMI rate ( Figure 3.8a ), one study was only used for HGD rate ( Figure 3.8b ) and four studies were only used for SMI rate of LSTs ≥20mm ( Figure 3.12 ). Of the 31 studies, 21 (17+4) reported histopathology data and endoscopic LST subtypes. Of these 21 studies, 15 provided the SMI rate in LST-G vs LST-NG ( Figure 3.9) , and seven of these provided the SMI rate for the endoscopic Kudo subtype.

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