Regional Variability in Survival for Patients Diagnosed with Selected Central Nervous System Tumours in Canada
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
General comments:
The manuscript is well written and contains relevant findings regarding variability in outcome related to regional volume and expertise. It addresses some hypotheses about this differences that were identified. As tumors are classified in Cancer Registries by ICD-O-3 histology and morphology codes, I would suggest to specify the ICD-O-3 morphology codes that were used to extract cases from the Cancer Registry Database.
Methods, Figures and Tables are properly designed and understandable. Some minor additions could be made (see below).
The conclusions are consistent. However, I would add to the limitations the unavailability of data from the Quebec regions. It should not be extensively explained, but adding it as a limitation would be appropriate.
The ethics and data availability statement are adequate, as is the referencing.
Specific comments: ( minor suggestions)
(73): Specify the ICD-O-3 morphology codes that were used to select patients ( just like you described the topo codes). you can also add in Table 1 (selected histology)
(116): for a non-Canadian somewhat difficult. A map with the regions and regional incidence/number of diagnoses vs. number of inhabitants would be helpful
(120): you might as well group into 0-4 years, as you group later on <1 and 1-4
(186): for GBM you describe large decrease in survival in the first 2 years. Although you describe 5-year survival, I suggest to add in the text for instance the 1- and/or 2y survival for GBM, as it are the generally stated survival times for this tumor type. You could also add it in Figure 1 legend.
(354) treatment modalities. Could there also be differences in treatment strategies across the regions, for instance more stereotactic biopsies in certain regions and more resections in higher volume regions. Or access to radiotherapy facilities? Could the authors comment on this or elaborate on this?
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
The topic is very interesting, but some points need to be addressed:
- Line 9: "Health care in Canada is managed by provinces/territories." Revised this sentence. why do the authors want to say this? what do you want to highlight?
- Lines 84-85: "We excluded patients with missing birth or death dates, as well as patients with death certificate or autopsy only diagnoses (n=640)." I think this represents an important limitation of the document. Discuss this choice.
- Lines 160-166. In the results section, authors should report a map (figure) with the five regions of Canada, so that the reader is more familiar with the geography of these regions.
- Lines 343-344: "Furthermore, the category of unclassified tumours, or malignant glioma NOS, are likely comprised of a heterogeneous..." It may be interesting to discuss the impact of survivorship bias in glioblastoma research. doi: 10.1016/j.critrevonc.2023.104065 -- doi: 10.1016/j.bbagen.2023.130428
- Lines 366-368: "We found evidence of regional variation in survival, with the most favourable survival outcomes in Ontario relative to all other regions, for all histological types analyzed..." How do the authors explain this better overall survival? It's not easy to understand this reading this paper. Improve this part.
Comments on the Quality of English Language
Minor editing of English language required
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors
Ref: curroncol-2992768
Title: Regional Variability in Survival for Patients Diagnosed with Selected Central Nervous System Tumours in Canada
Journal: Current Oncology
Reviewer’s comments
The topic addressed by this paper (a descriptive analysis of regional differences in survival of SNC patients) is really noteworthy and interesting; the study appears well planned; the methods and statistical analysis are clearly described and correctly applied; the results are consequent and presented with clearness; the discussion is well developed.
So, in my opinion the paper could be suitable for publication. I have only very few points to signal, hoping they could be useful to further improve the quality of the paper, which is already very high. In the following I report my comments on the manuscript.
I have no conflicts of interest to declare.
Specific comments:
1. All the text should be carefully checked for missing or unnecessary blanks.
2. Please check (and fix where necessary) the way of writing the terms “provinces” (with lowercase initial letter) and “territories” (lowercase or uppercase initial letter, according to the situation).
3. Line 62: please add some more details on “the T1 Personal Master File” for non-Canadian readers.
4. “Pan-Age Cohort” or “Pan Age Cohort” or “pan-age cohort”? Please standardize the way of writing this term.
5. A map of Canada reporting provinces and territories could be useful to better understand the geographical description in section 2.3.
6. Line 134: the acronym RDC must be previously defined, presumably at line 67.
7. Results: please check the correspondence between the data showed in Table 1 and those reported in the text; in particular at line 162 (Prairie provinces) and line 165 (Ontario 5-year OS probability).
8. Figures 3 and 4 have some layout problems to fix (numbers and words doubled and partially overlapping).
9. Lines 283-284: “…leading to an increased the volume of patients treated in the region”; sentence to check.
Comments on the Quality of English Language
Lines 283-284: “…leading to an increased the volume of patients treated in the region”; sentence to check.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for Authors
Good
Comments on the Quality of English Language
Minor editing of English language required
