COVID-19 Impact on Diagnosis and Staging of Colorectal Cancer: A Single Tertiary Canadian Oncology Center Experience

Round 1

Reviewer 1 Report

The authors report results of a single center retrospective study evaluating the impact of the COVID pandemic on the diagnosis and staging of colorectal cancer (CRC). Overall, they found that the rate diagnosis/mo was lower during the initial 15 month pandemic period compared to the preceding 26mo pre-pandemic period, with longer wait times to colonoscopy for FIT+ screen patients, however they found no differences in surgery rates or wait times, or cancer stage distribution between groups.  

Major concerns:

1. The authors need to clearly describe the impact of the pandemic restrictions on access to diagnostic procedures (FIT and colonoscopy) relative to pre-pandemic baseline, and how these access restrictions varied over the initial 15months of the pandemic at their center. They suggest in the introduction, that there was a severe decrease in access to FIT and colonoscopy from mid-March to May 2020, but they need to describe what happened after June 2020, because their study period extends to June 30, 2021.  Could there possibly have been 2 categories of restricted access to tests during the study period, one early in the pandemic associated with severe restrictions (stopping screening programs closing endoscopy suites, etc), and a second period through the remainder of the pandemic when services were restored but activity did not return completely to pre-pandemic levels?  If so, the latter should be described in more detail (degree of restriction, dates, utilization data). They should avoid vague terms such as “lockdown” (line 61) and instead report utilization data, or better describe policy changes over time.   Specifically, the authors should describe what happened to CRC screening programs at different times during the pandemic (how many FIT tests were performed and how many P3 colonoscopies for FIT+ screens were performed during different months or quarters?).
2. The authors should clarify the actual study period. They seem to report all CRC diagnoses during the pandemic, but state (line 68-69) that they only collected data regarding colonoscopy, surgery, and staging from Nov 2020-Aug 2021.  The Aug 2021 data extends beyond the June 30, 2021 data stated above.  Does this relate to when the researchers reviewed charts, or does it mean the study period extended to Aug, and these data were included for CRC diagnoses between Nov 202-Aug 2021?   
3. A major objective and endpoint of the study was to evaluate cancer stage pre- and pot-pandemic, however table 2 indicates a very large proportion of unknown stages (26% pre- and 37% post-pandemic. Why is there such a large proportion of unknown stages when this study had a single center retrospective design?  Why cannot the charts of these 113 patients be reviewed to find the stage data?  Did stage data differ early vs later in the pandemic, given that it may take several months of diagnostic delay to impact cancer stage?  
4. Some of the data reported in the abstract are different than data reported in the paper (patient numbers, diagnoses/mo) and needs to be fixed.
5. In the discussion section of the paper, the authors state that they could not find any evidence that diagnostic delays from COVID resulted in any stage in cancer stage, but then seem to make recommendations to enhance screening procedures based upon the hypothesis that diagnostic delays will result in higher cancer mortality despite their own study results. The authors should perhaps instead describe what other studies have been completed, or suggest what types of further studies should be performed to determine whether their concerns are valid.    

 

Minor concerns:

1. The authors should reference, and discus their results in context of another Canadian study reporting impact of COVID on CRC diagnoses (Int J Environ Res Public Health. 2021 Aug 28;18(17):9098.)
2. In describing colonoscopy priority levels, how is “clinically suspected CRC” defined for the P2 level? (line 76)
3. The authors report (line 98) that no consent form was obtained because the study was monocentric and retrospective. However, these alone are not justification for a waiver of consent. They then state that they received ethics approval to conduct the study.  Perhaps they should simply state that the ethics committee granted a waiver of consent due to the minimal risk retrospective study design, and lack of feasibility of obtaining consent from all study subjects.
4. The ratios of male/female CRCs in the pre- and post-pandemic periods seems to be reversed in line 109. The authors should clarify which ratio of male/female applies to which study period.
5. Table 1 should include p values for colonoscopy performed during hospitalization, and colonoscopy priority.
6. Grammar should be improved throughout the paper. For example, line 158 states that “…COVID pandemic hit hardly the province of Quebec….”, and could be reworded to ….hit the province hard…or omit that part of the sentence completely and state….The COVID pandemic had a profound impact on the Quebec health care system….   That said the authors did not report/reference the Quebec COVID infection and hospitalization rates in the introduction of the paper.   

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Reviewer comments and suggestions

The study understands the relationship between COVID-19 infection on the diagnosis and staging of colorectal cancer (CRC). Newly diagnosed CRC cases were divided into 2 groups based on the study time period: pre-pandemic (1/1/2018-12/3/2020), and pandemic (13/3/2020- 30/6/2021). 

Various techniques were used for the diagnosis during the pandemic period and were compared to the pre-pandemic period. The study result included 280 CRC diagnoses during the pre-pandemic period in comparison to 127 during the pandemic period. 

Mean diagnosis rates were lower during the pandemic period and colonoscopy deadlines were less respected in the pandemic period. The rate of elective surgery did not differ and mean delays were equal.

The study concluded that the COVID-19 pandemic led to overall less CRC diagnosis and increased endoscopic delays without a higher rate of advanced-stage disease. 

Based on my view, below are the comments that need to be incorporated in the revised version of the manuscript. 

1. Line 37; multiple studies have documented similar impacts of the pandemic on CRC screening, the authors have to mention at least 3-4 references
2. Line 40, a typo error was seen, et al. please modify it
3. Line 70-80 It would be better to prepare a ray diagram for the good presentation
4. In discussion figure 1 should be discussed with elaboration. The authors have to be adviced to see the results of recent studies that relates with other cancer and COVID.
5. Line 160 does not need to mention the aim, better to present your result in the first para.
6. Line 207 why it is so?
7. A conclusion para is needed in the MS

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Thank you very much for allowing me to review the article entitle “COVID-19 Impact on Diagnosis and Staging of Colorectal Cancer: A Single Tertiary Canadian Oncology Center Experience” (curroncol-1692420).

 

This is an interesting study at the Montreal University Health Care Center hospital, in which it is proposed to evaluate the impact of COVID-19 pandemic on diagnostic and therapeutic procedures of newly diagnosed CRC cases. Although it is a study located in a hospital concrete with its own characteristics allows to identify that delays to surgery were quite similar once the CRC diagnosis was established.

In the summary there are acronyms that do not explain how CHUM.

In the introduction it should be expanded indicating the importance of the delay in the diagnosis in the evolution of the patient and the hypothesis must be prior to the approach of the objective.

In material and method, the approval number of the study must be indicated. I suggest incorporating a figure that allows identifying the procedure of the two groups studied as individuals treated by the hospital and participants with suspected CRC. The methodology of epidemiological analysis of the data should be better explained.

Results: In the tables, p-values ​​must be indicated to which test they correspond. Table 1 lacks comparisons (p-values).

Discussion : It is clearly stated reflecting on the impact of the pandemic but I think that among the limitations it should be taken into account that those hospitals with less staff or those with a more saturated health system, the impact on the delay in DCRC diagnosis may have been much elder .

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have adequately addressed all concerns.