Reviewer's report
Title:Predictive Value of Metabolic 18FDG-PET Response on Outcomes in
Patients with Locally Advanced Pancreatic Carcinoma Treated with Definitive
Concurrent Chemoradiotherapy
Version: 1Date:20 August 2011
Reviewer: Lena Specht
Reviewer's report:
This manuscript examines the prognostic value of PET-response to
chemoradiotherapy in 32 patients with locally advanced pancreatic cancer.
Patients had a FDG-PET-CTscan before therapy (which was used for planning
radiotherapy) and 12 weeks after the end of treatment. They show that a good
metabolic response was associated with a significantly better prognosis. This is
in accordance with findings in many other tumour types, but is has not been
demonstrated extensively in pancreatic cancer. The authors mix local and distant
recurrences, although they would seem to be qualitatively different, the local
ones due to the ineffectiveness of chemoradiotherapy, the distant ones due to
lack of effectiveness of the chemotherapy. However, with so few patients this is
probably the best that can be done.
Major compulsory revision: The authors claim that the PET-response had
independent prognostic importance when other factors were taken into account
in multivariate analysis, using the Cox model. However, they do not state which
other factors were taken into account (are all the really important ones
included?), how these factors were scored in the analysis, how the analysis was
carried out (e.g., forward or backward selection), and which factors were in the
final model. This information is crucial when evaluating whether PET-response
really has independent prognostic significance. When the multivariate analysis is
done it must be taken into account that there are only 26 events (failures) in total,
and that therefore only a limited number of different factors can be analysed in a
Cox model at the same time. Also, the assumptions underlying the Cox model
(proportional death intensities) must be demonstrated to hold. Statistical
assistance is advised.
Minor essential revision: The numbers in Table 2 to not add up. With a total
number of patients of 32, 16 males and 8 females is too little.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:Predictive Value of Metabolic 18FDG-PET Response on Outcomes in
Patients with Locally Advanced Pancreatic Carcinoma Treated with Definitive
Concurrent Chemoradiotherapy
Version: 1Date:20 August 2011
Reviewer: Lena Specht
Reviewer's report:
This manuscript examines the prognostic value of PET-response to
chemoradiotherapy in 32 patients with locally advanced pancreatic cancer.
Patients had a FDG-PET-CTscan before therapy (which was used for planning
radiotherapy) and 12 weeks after the end of treatment. They show that a good
metabolic response was associated with a significantly better prognosis. This is
in accordance with findings in many other tumour types, but is has not been
demonstrated extensively in pancreatic cancer. The authors mix local and distant
recurrences, although they would seem to be qualitatively different, the local
ones due to the ineffectiveness of chemoradiotherapy, the distant ones due to
lack of effectiveness of the chemotherapy. However, with so few patients this is
probably the best that can be done.
Major compulsory revision: The authors claim that the PET-response had
independent prognostic importance when other factors were taken into account
in multivariate analysis, using the Cox model. However, they do not state which
other factors were taken into account (are all the really important ones
included?), how these factors were scored in the analysis, how the analysis was
carried out (e.g., forward or backward selection), and which factors were in the
final model. This information is crucial when evaluating whether PET-response
really has independent prognostic significance. When the multivariate analysis is
done it must be taken into account that there are only 26 events (failures) in total,
and that therefore only a limited number of different factors can be analysed in a
Cox model at the same time. Also, the assumptions underlying the Cox model
(proportional death intensities) must be demonstrated to hold. Statistical
assistance is advised.
Minor essential revision: The numbers in Table 2 to not add up. With a total
number of patients of 32, 16 males and 8 females is too little.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:Predictive Value of Metabolic 18FDG-PET Response on Outcomes in
Patients with Locally Advanced Pancreatic Carcinoma Treated with Definitive
Concurrent Chemoradiotherapy
Version: 1Date:20 August 2011
Reviewer: Lena Specht
Reviewer's report:
This manuscript examines the prognostic value of PET-response to
chemoradiotherapy in 32 patients with locally advanced pancreatic cancer.
Patients had a FDG-PET-CTscan before therapy (which was used for planning
radiotherapy) and 12 weeks after the end of treatment. They show that a good
metabolic response was associated with a significantly better prognosis. This is
in accordance with findings in many other tumour types, but is has not been
demonstrated extensively in pancreatic cancer. The authors mix local and distant
recurrences, although they would seem to be qualitatively different, the local
ones due to the ineffectiveness of chemoradiotherapy, the distant ones due to
lack of effectiveness of the chemotherapy. However, with so few patients this is
probably the best that can be done.
Major compulsory revision: The authors claim that the PET-response had
independent prognostic importance when other factors were taken into account
in multivariate analysis, using the Cox model. However, they do not state which
other factors were taken into account (are all the really important ones
included?), how these factors were scored in the analysis, how the analysis was
carried out (e.g., forward or backward selection), and which factors were in the
final model. This information is crucial when evaluating whether PET-response
really has independent prognostic significance. When the multivariate analysis is
done it must be taken into account that there are only 26 events (failures) in total,
and that therefore only a limited number of different factors can be analysed in a
Cox model at the same time. Also, the assumptions underlying the Cox model
(proportional death intensities) must be demonstrated to hold. Statistical
assistance is advised.
Minor essential revision: The numbers in Table 2 to not add up. With a total
number of patients of 32, 16 males and 8 females is too little.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
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