The Evolving Role for Repeat Molecular Testing in Metastatic Colorectal Cancer

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this manuscript, the authors reviewed repeat molecular testing in metastatic    colorectal cancer, and provided the perspective for guidance for next therapy and clinical trial enrollment. Generally, this review is well prepared and written. A minor revision is required for the publication in Cancers.

1. In the Introduction, it should add the analysis if there is related review in this topic, and highlight urgent need of this review in the last paragraph;
2. For part 3.1, it is better to prepare a Table to compare tissue vs blood-based testing;
3. It may be informative if add the description and discussion about the connection between the detection results and the stage of cancers;
4. Throughout the whole manuscript, it is better to define the repeat times for tests;
5. It is better to add a perspective in the Conclusion.

Author Response

Please see the attachment. 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Reviewer:

Recommendation: This paper may be publishable after major revision; I would like to be invited to further review.

 

Comments:

This manuscript provides a comprehensive and well-organized overview of the evolving role of repeat molecular testing in metastatic colorectal cancer. The review is detailed and highly informative, synthesizing current evidence from both clinical trials and molecular studies. The discussion around test modalities, biomarker discordance, and implications for clinical management is thorough and timely. The figures and tables are helpful for clarifying key concepts, although additional clarity in legends would improve accessibility. While the limitations of repeat molecular testing—such as heterogeneity and assay discordance—are acknowledged, further elaboration on practical clinical algorithms and health policy issues would enhance the manuscript. The inclusion of patient-centered perspectives and real-world data is encouraged to broaden the clinical relevance. Overall, this is a valuable scholarly contribution that will benefit clinicians and researchers working with mCRC, and with some further refinement, it will be highly impactful for the field.

Regarding specific questions, I would like the authors to address the following points prior to acceptance:

 

Major comments:

1. Could the authors synthesize existing recommendations across organizations into a dedicated section to clarify current clinical guidelines and practice gaps in sequential molecular testing for mCRC?
2. Have the authors considered including real-world data from large databases or registries to strengthen the discussion on repeat testing patterns and outcomes?
3. Can the comparison between ctDNA and tissue-based assays be expanded with a more critical analysis of discordances and their implications for clinical decision-making?
4. Would the manuscript benefit from a more detailed discussion of novel biomarkers, including current and potential clinical applications and ongoing trials?
5. Could the discussion on clonal evolution and resistance mechanisms be enhanced with more mechanistic insights, graphical timelines, or key studies illustrating dynamic mutation changes over therapy?
6. For each biomarker listed in the tables, can the authors add references for discordance rates and specify whether the values are from single studies or meta-analyses?
7. How should practitioners interpret negative results in contexts of intratumoral heterogeneity, sampling bias, or low ctDNA shedding, and can this be discussed more thoroughly?
8. Would a clinical algorithm or flowchart help guide mCRC management decisions when repeat molecular testing is performed, and can the authors provide one?
9. Can the limitations section be expanded to discuss technical, sample-source, cost, access, and turnaround time barriers in more detail, along with research priorities?
10. Could the authors incorporate discussion of patient experiences, cost-effectiveness, and health policy considerations for repeat molecular testing?

Minor Comments

1. Can the graphical abstract be improved with detailed legends for all symbols and a clearer visual link between molecular testing results and treatment options?
2. Have all references been checked for consistent formatting according to journal standards?
3. Will the authors consider clarifying abbreviations such as "pMMR," "dMMR," and "MAF" throughout the manuscript for readers unfamiliar with these terms?
4. Has the manuscript been carefully proofread to eliminate minor grammatical and typographic errors that persist in the text?
5. Could trial registration numbers (e.g., NCT numbers) be included for major studies mentioned to aid reader accessibility?

 

Author Response

Please see the attachment. 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Comments

The work of Kendersky N., et al entitled “The evolving role for repeat molecular testing in metastatic colorectal cancer” summarizes the biological rationale for repeat molecular assessment in mCRC. The subject is highly important since the molecular profiling in this cancer is central in the selection of therapies. The study is well designed, results well presented and conclusions well supported by the results. Finally, the manuscript is suitable for Cancers.

                                 

 

Major comments

1. Some paragraphs need more references. For instance, Line 52 and 63
2. The introduction needs more information on the therapeutic strategies applied and the methods used for molecular profiling. Compare to the innovative NGS.
3. Add the study limitations and future perspectives
4. It would be important to add a section on the impact that this new approaches might have on patient outcomes

 

 

Minor comments

Line 49 – enumerate examples of targeted therapies and immunotherapies applied in mCRC

Line 70 – Add the temporal date of the search and a figure/table with the organogram of the search with the inclusion and exclusion, as well as the numbers

Author Response

Please see the attachment. 

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

Title: Appropriately presented. I am also interested in metastatic colorectal cancer, and the clinical necessity and limitations of molecular testing were presented.

1. Lack of clarity in the methodology section
Issues:
The article only mentions "searching PubMed/MEDLINE, Embase, and ClinicalTrials.gov," but the specific search strategy (such as, combination of search terms, time period, filter criteria) is missing. (Section 2)
This was conducted as a narrative review, not a systematic review, but the potential for selection bias was not addressed.
Exclusion criteria (such as, "excluding non-CRC tissue") were ambiguous, and no PRISMA flow diagram or data extraction method was provided.

2. Statistical points
While heterogeneity related to RAS, BRAF, and HER2 is an important point, is it possible to definitively address this in section 3.3? It is questionable. According to this review, I understood that high TMB was more frequently observed in ctDNA. I could be mistaken. However, a more detailed discussion of the technical variability between platforms (such as, Guardant360 vs. FoundationOne) seems necessary.

3. Specificity of Table 1
Researchers will likely refer to this review paper by searching Google Scholar or PubMed with keywords such as "colorectal cancer metastasis." Table 1 will be heavily referenced, but the legend and related explanations for Table 1 are very inadequate. Simply reading the legend should provide an understanding of the meaning of each column and point in the table. Additionally, treatment strategies (such as, drug selection) should be presented when each result is obtained in clinical practice.

4. Lack of Specificity in Table 2 and Future Research Directions
I am conducting research on colorectal cancer metastasis. I was hoping to gain insights related to my research direction, but this review paper is disappointing. It does not provide any clinical applicability or innovative approaches. Specifically, I printed out 16 pages of paper to review this review and read it meticulously for an hour and a half, but I GAINED NO INSIGHT into its clinical applicability. 

5. This review is strong in that it summarizes the clinical value of repeat testing in metastatic colorectal cancer, and it also addresses factors related to heterogeneity and treatment resistance, such as RAS, BRAF, and HER2. However, the description is shallow and lacks a clear description of its CLINICAL APPLICABILITY.

6. Recently, generative AI, such as ChatGPT, has emerged, enabling immediate clinical insights into metastatic colorectal cancer. However, the question remains: Will this paper truly be useful in clinical practice?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Reviewer:

Recommendation: This manuscript is publishable as it is. 

Comments:

The authors have made significant corrections at appropriate parts of the manuscript. I really appreciate their efforts. I hope it will be published in its current form. 

Comments for author File: Comments.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors replied successfully to all my comments.