Title: Prognostic significance of serum CA125 in the overall management for patients with
gastrointestinal stromal tumors
Version: 1 Date: 29 Sep 2022
Reviewer's report:
This is a nicely written retrospective study about the predictive value of CA125 in patients
with resected gastrointestinal stromal tumours. The authors found that post operative abnormal
CA125 levels in GIST are associated with poorer outcome and found this to be an independent
prognostic factor.
The rationale for specifically using CA125 as prognostic tumour marker is not completely clear.
Why not CA199 or CEA? The authors mention a 'few studies' that report the association between
CA125 levels and outcome in GIST patient, however there is no reference to this.
The major concern regarding this study is the very small patient numbers within the context of
the retrospective study design. Of the 406patient identified to have a surgical resection, only
46 patients were found to have a CA125 at baseline.  It implies a major selection bias, where
patients with large abdominal tumours with upfront unclear diagnosis were more likely to have
a CA125 at baseline and this would be likely high in these patients. Hence the association with
incomplete resection, rupture, large tumours, tumours with a high mitotic index etc.
What was the cut-off of CA125 values? What was the median and range in the population
described? Could the authors describe this for both the 'low' CA125 group and 'high' CA125
group?
In the design of the study it is not clear when the postoperative CA125 were obtained. If this
concerns a population identified over the course of 10 years, were these patients then asked to
repeat CA125 post hoc? And within this time, would patients have relapsed? At what time points
did the authors obtain a post operative CA125 and in how many patients was this performed
after they have relapsed?
And what proportion of patients was on a TKI at this point?
Title: Prognostic significance of serum CA125 in the overall management for patients with
gastrointestinal stromal tumors
Version: 1 Date: 29 Sep 2022
Reviewer's report:
This is a nicely written retrospective study about the predictive value of CA125 in patients
with resected gastrointestinal stromal tumours. The authors found that post operative abnormal
CA125 levels in GIST are associated with poorer outcome and found this to be an independent
prognostic factor.
The rationale for specifically using CA125 as prognostic tumour marker is not completely clear.
Why not CA199 or CEA? The authors mention a 'few studies' that report the association between
CA125 levels and outcome in GIST patient, however there is no reference to this.
The major concern regarding this study is the very small patient numbers within the context of
the retrospective study design. Of the 406patient identified to have a surgical resection, only
46 patients were found to have a CA125 at baseline.  It implies a major selection bias, where
patients with large abdominal tumours with upfront unclear diagnosis were more likely to have
a CA125 at baseline and this would be likely high in these patients. Hence the association with
incomplete resection, rupture, large tumours, tumours with a high mitotic index etc.
What was the cut-off of CA125 values? What was the median and range in the population
described? Could the authors describe this for both the 'low' CA125 group and 'high' CA125
group?
In the design of the study it is not clear when the postoperative CA125 were obtained. If this
concerns a population identified over the course of 10 years, were these patients then asked to
repeat CA125 post hoc? And within this time, would patients have relapsed? At what time points
did the authors obtain a post operative CA125 and in how many patients was this performed
after they have relapsed?
And what proportion of patients was on a TKI at this point?
Please review this paper.
user
Title: Prognostic significance of serum CA125 in the overall management for patients with
gastrointestinal stromal tumors
Version: 1 Date: 29 Sep 2022
Reviewer's report:
This is a nicely written retrospective study about the predictive value of CA125 in patients
with resected gastrointestinal stromal tumours. The authors found that post operative abnormal
CA125 levels in GIST are associated with poorer outcome and found this to be an independent
prognostic factor.
The rationale for specifically using CA125 as prognostic tumour marker is not completely clear.
Why not CA199 or CEA? The authors mention a 'few studies' that report the association between
CA125 levels and outcome in GIST patient, however there is no reference to this.
The major concern regarding this study is the very small patient numbers within the context of
the retrospective study design. Of the 406patient identified to have a surgical resection, only
46 patients were found to have a CA125 at baseline.  It implies a major selection bias, where
patients with large abdominal tumours with upfront unclear diagnosis were more likely to have
a CA125 at baseline and this would be likely high in these patients. Hence the association with
incomplete resection, rupture, large tumours, tumours with a high mitotic index etc.
What was the cut-off of CA125 values? What was the median and range in the population
described? Could the authors describe this for both the 'low' CA125 group and 'high' CA125
group?
In the design of the study it is not clear when the postoperative CA125 were obtained. If this
concerns a population identified over the course of 10 years, were these patients then asked to
repeat CA125 post hoc? And within this time, would patients have relapsed? At what time points
did the authors obtain a post operative CA125 and in how many patients was this performed
after they have relapsed?
And what proportion of patients was on a TKI at this point?
assistant