Reviewer's report
Title:Increasing late stage and mortality of colorectal cancer demonstrates the
need for screening: a population based study in Ireland, 1994-2010.
Version:2Date:27 February 2014
Reviewer: Andrew McKay
Reviewer's report:
The authors have addressed an important topic – the trends in colorectal cancer
in Ireland prior to the introduction of a screening problem. This is a nicely done
and well-written paper. I do have a few comments:
1. I agree that the trend towards a later stage at diagnosis is very likely due to a
stage migration phenomenon due to better staging, especially with the increased
availability and increased quality of CT and other imaging. Does the available
data set contain any information about the use of preoperative investigations
such as the use of CT or other imaging? Are there other recent papers which
have also found this trend and/or attempted to explain it?
2. The rise in ASMR’s for rectal cancer is a concerning finding that does require
more research. The authors suggest that underuse of preoperative radiotherapy
may be partly to blame. Moving from a time where preoperative radiation was
rarely used to a more recent time where preoperative therapy is considered
standard and more commonly used really should not cause the ASMR’s to go up.
At least it is not intuitive that it should happen. If preoperative treatment is
underused, there really should be no change.
I wonder if the increase in neoadjuvant/preoperative radiation or chemoradiation
could be responsible for this finding, but in a different way. Rectal cancers are
treated differently than colon cancers, so it is important to distinguish between
the two sites of disease. The ICD-10 system contains three codes for colorectal
cancer – C18 for colon cancer, C20 for rectal cancer, and C19 for cancers of the
rectosigmoid junction. Categorizing a tumor as a rectosigmoid cancer, rather
than as a colon or rectal cancer is problematic since a decision really must be
made to treat the tumor according to the paradigm for colon cancer or the
paradigm for rectal cancer, not something in between. With the modern use of
neoadjuvant chemoradiation, physicians who treat rectal cancer are much more
aware of the need to accurately determine if it is rectal or colon cancer. Thus, the
ICD-10 code for rectosigmoid cancer may be used much less frequently in later
years. There may have been a considerable number of upper rectal caners that
in early years were called colon cancers (rectosigmoid lesions) when in later
years they were more correctly labeled as rectal cancers. Since these tumors
carry a slightly worse prognosis than colon cancers, this may have resulted in an
artificial decrease in ASMR’s for colon cancer and an artificial increase in ASMR
for rectal cancer. Was there a decrease over time in the proportion of
rectosigmoid cancers that could explain this?
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:Increasing late stage and mortality of colorectal cancer demonstrates the
need for screening: a population based study in Ireland, 1994-2010.
Version:2Date:27 February 2014
Reviewer: Andrew McKay
Reviewer's report:
The authors have addressed an important topic – the trends in colorectal cancer
in Ireland prior to the introduction of a screening problem. This is a nicely done
and well-written paper. I do have a few comments:
1. I agree that the trend towards a later stage at diagnosis is very likely due to a
stage migration phenomenon due to better staging, especially with the increased
availability and increased quality of CT and other imaging. Does the available
data set contain any information about the use of preoperative investigations
such as the use of CT or other imaging? Are there other recent papers which
have also found this trend and/or attempted to explain it?
2. The rise in ASMR’s for rectal cancer is a concerning finding that does require
more research. The authors suggest that underuse of preoperative radiotherapy
may be partly to blame. Moving from a time where preoperative radiation was
rarely used to a more recent time where preoperative therapy is considered
standard and more commonly used really should not cause the ASMR’s to go up.
At least it is not intuitive that it should happen. If preoperative treatment is
underused, there really should be no change.
I wonder if the increase in neoadjuvant/preoperative radiation or chemoradiation
could be responsible for this finding, but in a different way. Rectal cancers are
treated differently than colon cancers, so it is important to distinguish between
the two sites of disease. The ICD-10 system contains three codes for colorectal
cancer – C18 for colon cancer, C20 for rectal cancer, and C19 for cancers of the
rectosigmoid junction. Categorizing a tumor as a rectosigmoid cancer, rather
than as a colon or rectal cancer is problematic since a decision really must be
made to treat the tumor according to the paradigm for colon cancer or the
paradigm for rectal cancer, not something in between. With the modern use of
neoadjuvant chemoradiation, physicians who treat rectal cancer are much more
aware of the need to accurately determine if it is rectal or colon cancer. Thus, the
ICD-10 code for rectosigmoid cancer may be used much less frequently in later
years. There may have been a considerable number of upper rectal caners that
in early years were called colon cancers (rectosigmoid lesions) when in later
years they were more correctly labeled as rectal cancers. Since these tumors
carry a slightly worse prognosis than colon cancers, this may have resulted in an
artificial decrease in ASMR’s for colon cancer and an artificial increase in ASMR
for rectal cancer. Was there a decrease over time in the proportion of
rectosigmoid cancers that could explain this?
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:Increasing late stage and mortality of colorectal cancer demonstrates the
need for screening: a population based study in Ireland, 1994-2010.
Version:2Date:27 February 2014
Reviewer: Andrew McKay
Reviewer's report:
The authors have addressed an important topic – the trends in colorectal cancer
in Ireland prior to the introduction of a screening problem. This is a nicely done
and well-written paper. I do have a few comments:
1. I agree that the trend towards a later stage at diagnosis is very likely due to a
stage migration phenomenon due to better staging, especially with the increased
availability and increased quality of CT and other imaging. Does the available
data set contain any information about the use of preoperative investigations
such as the use of CT or other imaging? Are there other recent papers which
have also found this trend and/or attempted to explain it?
2. The rise in ASMR’s for rectal cancer is a concerning finding that does require
more research. The authors suggest that underuse of preoperative radiotherapy
may be partly to blame. Moving from a time where preoperative radiation was
rarely used to a more recent time where preoperative therapy is considered
standard and more commonly used really should not cause the ASMR’s to go up.
At least it is not intuitive that it should happen. If preoperative treatment is
underused, there really should be no change.
I wonder if the increase in neoadjuvant/preoperative radiation or chemoradiation
could be responsible for this finding, but in a different way. Rectal cancers are
treated differently than colon cancers, so it is important to distinguish between
the two sites of disease. The ICD-10 system contains three codes for colorectal
cancer – C18 for colon cancer, C20 for rectal cancer, and C19 for cancers of the
rectosigmoid junction. Categorizing a tumor as a rectosigmoid cancer, rather
than as a colon or rectal cancer is problematic since a decision really must be
made to treat the tumor according to the paradigm for colon cancer or the
paradigm for rectal cancer, not something in between. With the modern use of
neoadjuvant chemoradiation, physicians who treat rectal cancer are much more
aware of the need to accurately determine if it is rectal or colon cancer. Thus, the
ICD-10 code for rectosigmoid cancer may be used much less frequently in later
years. There may have been a considerable number of upper rectal caners that
in early years were called colon cancers (rectosigmoid lesions) when in later
years they were more correctly labeled as rectal cancers. Since these tumors
carry a slightly worse prognosis than colon cancers, this may have resulted in an
artificial decrease in ASMR’s for colon cancer and an artificial increase in ASMR
for rectal cancer. Was there a decrease over time in the proportion of
rectosigmoid cancers that could explain this?
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests
assistant