Review for 10.1186/s12876-024-03187-x (2024)

Title: Endoscopic diagnosis of gastric and oesophageal cancer in Lusaka, Zambia: A
retrospective analysis
Version: 1 Date: 09 Nov 2023
Reviewer's report:
Review: Endoscopic diagnosis of gastric and oesophageal cancer in Lusaka, Zambia: A
retrospective analysis
The authors must be congratulated on having a multi-decade report on gastroscopy findings
in Africa, which is a rarity. I have a few suggestions, which will improve the paper, and its
interpretability.
1. Please state the total number of endoscopes performed in the period under review in the results
section, and the number of records that were excluded because of lack of demographic data as
stated in the methods section. This enables independent assessment of the quality of the dataset,
and how representative it is. Did the introduction of an electronic record system in 2015 translate
to more reports with complete data?  Please also state the years (if any, in which endoscopy was
not available). What other endoscopy services are available within Lusaka?
2.  The number of endoscopies increased from 2010, and with it, the number of cancer diagnoses.
This suggest that introducing training has a direct impact on service provision, and perhaps the
authors could offer insights in this regard? Additionally, how has the inclusion of diagnoses
from trainees affected the dataset? Are they observed for all procedures? Were the records more
complete?
3. Endoscopic equipment has changed over the years – there was a shift from fibrescopes to
videoscopes, then the introduction of HD monitors & capacity. When did these shifts occur in
the unit, and how may this have affected the findings? (This may also impact on the diagnoses
of gastric ulcers, with small mucosal erosions recognised and classified as ulcers over time.
4. Table 2: What are the two p values referring to? Was the table analysed as a 5 x 2 table or
each decade was analysed separately, and has its own p value?  If the later was the case, then
one would expect a separate column with the appropriate p-values.
5. The lengthy discussion on symptoms and their diagnostic yield is not necessary since the
authors did not include the indications for the procedures in the results. The paragraph should
be refocussed onto the findings of the paper rather than becoming a commentary on indications
for endoscopy.
6. It seems like COVID is a more plausible reason for the reduction in ‘normal’ gastroscopies
in 2020 and 2021 than pre-screening of requests. The authors should add a bit more detail to
the unit’s response to COVID, and how this affected gastroscopy referrals even without the
screening. During COVID it is likely that the number of requests for gastroscopies fell, even
without pre-screening as awareness of the associated risks transcended GI units, particularly at
the beginning.
7.  Could the increase in oesophageal Ca simply be due to increasing awareness among Drs and
patients of the need for endoscopy in someone with dysphagia from oesophageal obstruction as
compared to the more protean presentations of gastric Ca?
8. The contribution of NSAIDs to gastric ulcers need to be stated more explicitly, rather than
implied. This is a confounder for the changes in the proportion of duodenal versus gastric ulcers.
Could perhaps, the use of low dose aspirin increasing with rising awareness of NCDs? Do
the authors know of any references regarding the use of NSAIDS and the availability of OTC
NSAIDs in Zambia, and the region? This would strengthen the paper.
9. One minor point – the authors should consider replacing the word ‘reducing’ throughout the
paper with ‘decreasing’. It reads better.