Table 2.

Checklist for data collection and reporting of studies of incidence gastric cancer in patients with GIM and comparative cohort studies of the risk factors for developing gastric cancer in GIM patients (modifiers for studies of the prevalence of GIM and comparative studies of the risk factors for finding GIM are outlined in the footnote)

Section/topic	Item no.	Checklist item
Title and Keywords	1	-
Abstract	2	-
Introduction	3	Regional gastric cancer data for study site(s)
	3a	Gastric cancer incidence and mortality (e.g. IARC data)
	3b	GIM prevalence (if known)
	3c	Description of regional practices and policies for GC screening/surveillance
Methods: Recruitment	4*	Consecutive or randomly selected patients from a predefined population
Methods: Patient information	5a	Demographics: age, gender, race and ethnicity, country and region, country of origin and immigration history.
	5b	Medical history: history of gastric cancer/HGD (included or excluded), GIM (prior endoscopy), gastric surgery (indication, type, date), pernicious anemia/autoimmune gastritis, hereditary GI/gastric syndrome(s)
	5c	Historical features: first degree family history of stomach cancer, smoking history (quantified), alcohol use history (quantified), dietary habits (salt intake, fruits and vegetables, dairy products)
	5d	Medication history: recorded use and duration (e.g. proton pump inhibitor, aspirin, nonsteroidal anti-inflammatory drugs, antioxidants)
	5e	H pylori status, labs, and treatment history Status: ever-infected (any positive H pylori test), current infection (positive active H pylori test), prior infection (positive serology and neg active H pylori test) Labs: blood-based (serology), non-invasive (stool antigen, urea breath testing), endoscopy-based (rapid urease test, histology), other (PCR, culture), virulence factors (cagA and vacA) Treatment: never-treated, treatment (<1 year vs > 1 year ago), post-treatment testing (yes/no), H pylori eradication success (yes/no)
	5f	Laboratory assessment: pepsinogens, autoimmune gastritis and pernicious anemia serologies (parietal and/or intrinsic factor antibodies)
Methods: Endoscopy evaluation	6a	Endoscopy Imaging modality (yes/no for each): white light endoscopy, image-enhanced endoscopy (magnification, chromoendoscopy (e.g. indigo carmine), virtual chromoendoscopy (e.g. narrow-band imaging), other)
	6b	Endoscopy quality measures (yes/no) (e.g., visualization quality, distension, visual mapping, duration)
Methods: Endoscopy biopsy protocol	7	For index and follow-up endoscopies
	7a	Sydney system biopsies** (non-targeted): confirm number of biopsy sites and biopsies/site (1–2 biopsies at the Sydney protocol site), biopsy forceps (jumbo vs standard)
	7b	Targeted biopsies: protocol (yes/no)
Methods: Histological evaluation	8a	Global diagnosis (most advanced lesion: atrophic gastritis, intestinal metaplasia, dysplasia, carcinoma in situ), compartment diagnosis (antrum and corpus; consider incisura), other diagnoses (e.g. ulcer, autoimmune gastritis, polyp, etc.)
	8b	GIM extension: antrum, incisura, corpus, antrum/incisura and corpus
	8c	GIM histological subtype† (complete, incomplete, other), subtyping method (H&E, staining (e.g. mucins), other), GIM severity recorded (mild, moderate, severe)
	8d	Gastric scoring system use (yes/no), OLGA/OLGIM stages, other (e.g., Correa score)
Methods: Comparisons of interest	9‡	Race/ethnicity, immigration history, smoking history, alcohol use, dietary intake, first degree family history of gastric cancer, pepsinogens, pernicious anemia and autoimmune gastritis, H. pylori exposure and its virulence factors (cagA and vacA), histological subtype (complete vs. incomplete), topographical extent (extensive vs antrum-limited), OLGIM stage
Methods: Follow-up◊	10a	Follow up EGD (e.g. 1, 3, 5 and 10 years)
	10b	Progression interventions: none/natural history, H. pylori treatment, pharmacological agents, dietary, other
	10c	Semi-annual or annual clinic follow-up between endoscopies
	10d	Follow-up laboratory evaluation (e.g. biomarkers)
Methods: Outcomes§	11a	Early cancer detection stage 1 and 2; mortality from gastric cancer; overall mortality; complications associated with EGD; natural progression of GIM
	11b	Quality of life; cost-effectiveness on GIM treatment/surveillance
Methods: Statistical analysis	12a‖	Estimate the cumulative incidence at 1, 3, 5 and 10 years; estimate incidence rate
	12b‡, ¶	Estimate relative risk at 1, 3, 5, and 10 years; estimate incidence rate ratios
	12c‡, Δ	Must adjust for age, race/ethnicity, immigration history, first degree family history of gastric cancer, histological subtype, and topographical extent.
Results	13	-
Discussion	14	-
Informed consent	15	-

^*The suggested minimum sample size is 250.

^**The updated Sydney System: five biopsies encompassing one from the lesser curvature of the antrum within 2–3 cm of the pylorus, one from the great curvature of the antrum within 2–3 cm of the pylorus, one from the lesser curvature of the body 8 cm distal to the cardia, one from the great curvature of the body 8 cm distal to the cardia, and one from the incisura angularis.

^†Incomplete GIM may identify patients at higher risk for progression. Further studies are needed. Individual patient-oriented decisions are warranted in the interim, as noted in the guidelines.

^‡For comparative studies only

^◊Not applicable for studies of the prevalence of GIM

^§For prevalence of GIM studies: number of patients with GIM; number of patients with other preneoplastic lesions; number of patients with incomplete GIM; number of patients with extensive GIM; number of patients at different OLGIM stages

^‖For prevalence of GIM studies: Estimate of the prevalence of GIM

^¶For prevalence of GIM studies: Relative risk of finding GIM

^ΔFor prevalence of GIM studies: Must adjust for age, race/ethnicity, immigration history, smoking history, alcohol use, first degree family history of gastric cancer