Review for 10.1186/s12876-025-04177-3 (2025)

Title: The effectiveness of Radiotherapy and Transarterial Embolization for Advanced Gastric
Cancer Bleeding
Version: 2 Date: 20 May 2024
Reviewer's report:
I congratulate the authors on the manuscript investigating the role of RT vs TAE in the
management of bleeding from inoperable gastric cancers. This is an important topic, and the role
of TAE in the management of inoperable gastric cancers, in a comparative study with traditional
RT has not been well described.
I do have several comments:
1. I understand it is a retrospective study, thus it is prone to selection bias. I think it might
be important for the authors to explain in detail, what are the characteristics of the patients
who underwent TAE? Are these therapeutic TAEs, or prophylactic TAEs? This is because in
standard practice, the traditional approach for bleeding gastric cancer lesions will still involve
initial endoscopy. Even in the event where it is  not possible to achieve endosocpic hemostasis,
either surgical intervention (which can be quite morbid) or endoscopic temporising measures
(like hemospray/ endoclot) are usually done for temporising purposes.  Thus, are the patients
in the TAE group, those with more severe arterial bleeding, that failed endoscopic temporising
measures/ initial hemostasis, and thus needed an emergency angioembolisation? Might be good
for the authors to clarify given this is a retrospective study, how are the patients selected to
undergo TAE? Do they all have an arterial blush on CT scan demonstrating active arterial
bleeding? Or are they done prophylactically, but just to embolise the vessel going towards the
targeted tumour? Most of the time tumoural bleeding are venous in nature, hence RT which
works by eventual fibrosis of the tumour venules, eventually achieves hemostasis. Thus, I
wonder if the TAE group of patients may be dissimilar to the RT group given they may have
more severe bleeding/ arterial erosions/ pseudoaneurysms?
2. With regards to the informed consent process, it is a minor point, but I think it is important to
clarify if the participants consented for their data to be stored in the database, and subsequently,
the data is then used for this initial study? Or was it as what the authors described where
the "participation was contingent upon obtaining informed consent from all individuals after
thoroughly explaining the study's objectives and nature." If participants were enrolled since
2013, knowing that this study's "objectives and nature" was to compare RT vs TAE at the start,
then this is a prospective cohort study rather than a retrospective study reviewing the database
that was collected from 2013-2023. I think it is important for the authors to amend and clarify
that part.
3. "Inclusion criteria encompassed  cases where hemostasis via endoscopic intervention or
surgical procedures was deemed either challenging or unfeasible". Just to reiterate point 1 above,
so was there any attempts at endoscopy at all? If not, does that mean all bleeding were diagnosed
via imaging, which I presume is a CT mesenteric angiogram? Does that mean all patients have
an arterial blush or venous pooling seen on CT scan?
4. With regards to results paragraph 3, 77.8%  of patients in the TAE group completed planned
treatment. Can the authors elaborate on why TAE was not successful in the 22.2% of patients?
Was it an access issue, was it because the feeding vessel could not be identified, or was it
because during angiogram, the initial arterial blush/ active bleeding was not longer visualised
on mesenteric angiogram?
5. Will it be possible to give a breakdown on the number of patients who had inoperable bleeding
from the primary tumour, and the number of patients who had bleeding as a result of locoregional
recurrences after initial surgery?
6. Can the authors provide an explanation as to why the RT group had a higher number of patients
who received previous chemotherapy, while the TAE group had a higher number of patients
without any previous treatment? This is especially so given that (although not statistically
significant), the proportion of patients in the TAE group of a better performance status (ECOG
0-2) appeared higher than those in the RT group