Title: Is DEB-TACE  as  locoregional  therapy  before  liver  transplantation  for  hepatocellular
  carcinoma effective?
Version: 4 Date: 23 Aug 2024
Reviewer:  Ehab Elmongui
Reviewer's report:
Dear Authors,
I would like to commend you on your research efforts and excellent presentation of the results.
I acknowledge the difficulties you might encounter in recruiting sufficient sample size and that
you said it is a preliminary study that needs to be reproduced in a RCT with larger sample size.
The sample size of the current study is underpowered to detect medium effect sizes for the
included covariates. The table in the attached file presents the relationship between the event
rate in the reference group, the hazard ratio (HR) equivalent to a medium effect size, and
the minimum required sample size for a univariate Cox proportional hazard regression model
1. The minimum required sample sizes here were calculated for different event rates in the
reference category for any binary covariate assuming no correlation with other covariates using
the ‘ssizeEpi.default’ function from the ‘powerSurvEpi’ package in R 2. The parameters used
were the postulated hazard ratios equivalent to a medium effect size (theta) , a square of the
correlation between the covariate of interest and another covariate (rho²) of 0, a proportion of the
population in the reference category for any covariate (p) of 0.5, an event rate in the reference
group (psi), and a desired power of 0.8.
Ehab Elmongui, BPharmSc, PharmD, MSc, PhD (c)
Biostatistician
Title: Is DEB-TACE  as  locoregional  therapy  before  liver  transplantation  for  hepatocellular
  carcinoma effective?
Version: 4 Date: 23 Aug 2024
Reviewer:  Ehab Elmongui
Reviewer's report:
Dear Authors,
I would like to commend you on your research efforts and excellent presentation of the results.
I acknowledge the difficulties you might encounter in recruiting sufficient sample size and that
you said it is a preliminary study that needs to be reproduced in a RCT with larger sample size.
The sample size of the current study is underpowered to detect medium effect sizes for the
included covariates. The table in the attached file presents the relationship between the event
rate in the reference group, the hazard ratio (HR) equivalent to a medium effect size, and
the minimum required sample size for a univariate Cox proportional hazard regression model
1. The minimum required sample sizes here were calculated for different event rates in the
reference category for any binary covariate assuming no correlation with other covariates using
the ‘ssizeEpi.default’ function from the ‘powerSurvEpi’ package in R 2. The parameters used
were the postulated hazard ratios equivalent to a medium effect size (theta) , a square of the
correlation between the covariate of interest and another covariate (rho²) of 0, a proportion of the
population in the reference category for any covariate (p) of 0.5, an event rate in the reference
group (psi), and a desired power of 0.8.
Ehab Elmongui, BPharmSc, PharmD, MSc, PhD (c)
Biostatistician
Please review this paper.
user
Title: Is DEB-TACE  as  locoregional  therapy  before  liver  transplantation  for  hepatocellular
  carcinoma effective?
Version: 4 Date: 23 Aug 2024
Reviewer:  Ehab Elmongui
Reviewer's report:
Dear Authors,
I would like to commend you on your research efforts and excellent presentation of the results.
I acknowledge the difficulties you might encounter in recruiting sufficient sample size and that
you said it is a preliminary study that needs to be reproduced in a RCT with larger sample size.
The sample size of the current study is underpowered to detect medium effect sizes for the
included covariates. The table in the attached file presents the relationship between the event
rate in the reference group, the hazard ratio (HR) equivalent to a medium effect size, and
the minimum required sample size for a univariate Cox proportional hazard regression model
1. The minimum required sample sizes here were calculated for different event rates in the
reference category for any binary covariate assuming no correlation with other covariates using
the ‘ssizeEpi.default’ function from the ‘powerSurvEpi’ package in R 2. The parameters used
were the postulated hazard ratios equivalent to a medium effect size (theta) , a square of the
correlation between the covariate of interest and another covariate (rho²) of 0, a proportion of the
population in the reference category for any covariate (p) of 0.5, an event rate in the reference
group (psi), and a desired power of 0.8.
Ehab Elmongui, BPharmSc, PharmD, MSc, PhD (c)
Biostatistician
assistant