Review Reports

Round 1

Reviewer 1 Report

Overall a nice and clear review.

In general:

The impact on the adaptive immune response needs to be explained in the abstract (in connection with line 13-14), section 4 and 5.

An illustration showing the up- and downregulation of immune cells and cytokines in the aftermath of surgery would be useful (could be in realtion to line 168-169).

Specific:

line 39: it should be outlined that the tumor cells coated by platelets are circulating tumor cells.

line 66-67: Although increasing during surgery, it should be emphasized that a solid, invasive cancer release millions of cancer into the circulation every day during its years of existence, and not only in relation to surgery. The metastases occurring during the first years after surgery are the result of the activation of micrometastases being present already preoperatively.

line 81 (extracellular vesicles), line 107 (platelet microparticles) - the nature of exosomes (especially the tumor-secreted) should be explained and the term should be used instead of vesicles and particles (although not wrong per se).

line 105-106: "liver inflammatory surgical stress" should be rephrased.

line 138-143 rather belongs to section 5.

Refs:

33 of 80 refs. (>40%) are 10 years or older and not a marker of exeptional quality. Authors must check if more recent refs. are available.

Author Response

Overall a nice and clear review.

We are pleased that the manuscript was favorably reviewed and was found to be potentially acceptable for publication pending revisions.

We thank the reviewers for their valuable insight and comments as these serve to further strengthen our manuscript.

 

As requested, we have provided a point-by-point response to each of the reviewer’s comments with relevant changes made to the manuscript.

In general:

The impact on the adaptive immune response needs to be explained in the abstract (in connection with line 13-14), section 4 and 5.

We have rephrased the sentence in the abstract (line 13-14) to reflect that we aren’t solely focused on the innate immune response but also the adaptive immune response. Surgical stress has been shown to increase Treg recruitment and NK cell impairment, both parts of the adaptive immune response.

An illustration showing the up- and downregulation of immune cells and cytokines in the aftermath of surgery would be useful (could be in relation to line 168-169).

We have added a figure that focuses on the key mediators (immune cells and cytokines) that change in the aftermath of surgery.

 

Specific:

line 39: it should be outlined that the tumor cells coated by platelets are circulating tumor cells.

We have included this. This line now reads “These tumor cells coated by platelets are sometimes referred to as circulating tumor cells”

line 66-67: Although increasing during surgery, it should be emphasized that a solid, invasive cancer release millions of cancer into the circulation every day during its years of existence, and not only in relation to surgery. The metastases occurring during the first years after surgery are the result of the activation of micrometastases being present already preoperatively.

We have revised this line to include the following sentence “It is widely known that millions of cells are shed from solid tumors into the circulation daily however few clinically metastatic foci are formed.”

line 81 (extracellular vesicles), line 107 (platelet microparticles) - the nature of exosomes (especially the tumor-secreted) should be explained, and the term should be used instead of vesicles and particles (although not wrong per se).

Thank you for this point. We have defined the term tumor exosomes and included that to refer to our point in line 81.

The term “platelet microparticles”, used in line 107, is referring to fragments of platelet plasma membranes released into circulation. Although these are exosomes, we did not want the readers to confuse tumor exosomes described in line 81 with these platelet-derived exosomes used in this paragraph hence we have kept the term microparticle for this paragraph.

line 105-106: "liver inflammatory surgical stress" should be rephrased.

We have rephrased this sentence to read “Our group has shown that NETs can exacerbate distal organ injury (in the lung and kidney) after liver surgery through activation of systemic procoagulant state and diffuse microvascular immune thrombi”

line 138-143 rather belongs to section 5.

We have moved this paragraph to section 5

Refs:

33 of 80 refs. (>40%) are 10 years or older and not a marker of exceptional quality. Authors must check if more recent refs. are available.

The older references are the original and sentinel studies that investigated the link between surgical injury and tumor progression. We included these studies because they are vital in providing the mechanistic relationship surgical stress and tumor progression.  In fact, reviewer 2 has strongly suggested that we add some key older studies from the 90s and early 2000s which we have added to our revised manuscript. We have done an extensive literature search to include relevant and recent studies that support this work. We hope that the readers understand that we have not skipped on recent studies that cover this topic.

Reviewer 2 Report

The article by Onuma et al. is a short but concise review of mechanisms of immune suppression and promotion of cancer metastases. There are a few style comments and additional references to consider, which may improve the readability for non-expert readers and to ensure important studies are not overlooked:

 

1. Figure 1-3 are really very similar and don’t add much in terms of detail. Figure 2 makes reference to liver metastatic burden but the mets are shown in the lung. Consider adding some mechanistic details to the figures with the appropriate mediators, (i.e. P-selectin, HMGB, CXCL-4 etc…) to add value.
2. NETs are introduced in line 104 but the section on NETs follows (line 112). Consider changing the section to indicate that NETs are discussed further below or introduce what they are in this section.
3. HMGB is discussed in the section on platelets and the section on NETs with different effects. Please reference back to the first section, such as “As outlined in the previous section, not only does HMGB1 bind platelets via TLR4, it also activates TLR9-dependent….”
4. The section on therapeutics should reference some of the studies done in the 90s where perioperative immune stimulation with IFN-alpha or IL-2 was associated with improved immune parameters and, in a couple of studies, improved cancer outcomes. The largest of these is a phase II RCT where DFS was improved with perioperative IL-2 (Klatte 2006 British Journal of Surgery; PMID 17031403)
5. In line 216 you review the preclinical data for perioperative LMWH to reduce postoperative metastases. There is a clinical trial (PERIOP-01; NCT01455831) that is also asking this same question.
6. In the paragraph starting on line 219 you review the PERIOP-04 trial. There is no reference to the preclinical data for the trial which includes PMID: 24404430 and PMID: 29872554.
7. In the abstract, the sentence line 15 to 18 (starting with Similarly….) seems awkward. Consider revising.
8. The last statement before the concluding remarks (line 241) about PD-1 seems out of place. Please add more detail about what is known regarding PD-1 and the perioperative period or consider removing. There is nothing in the mechanism section about T cell exhaustion so talking about the therapeutic potential seems out of place.  

Author Response

The article by Onuma et al. is a short but concise review of mechanisms of immune suppression and promotion of cancer metastases. There are a few style comments and additional references to consider, which may improve the readability for non-expert readers and to ensure important studies are not overlooked:

We are pleased that the manuscript was favorably reviewed and was found to be potentially acceptable for publication pending revisions.We thank the reviewers for their valuable insight and comments as these serve to further strengthen our manuscript.

As requested, we have provided a point-by-point response to each of the reviewer’s comments with relevant changes made to the manuscript.

 

1. Figure 1-3 are really very similar and don’t add much in terms of detail. Figure 2 makes reference to liver metastatic burden but the mets are shown in the lung. Consider adding some mechanistic details to the figures with the appropriate mediators, (i.e. P-selectin, HMGB, CXCL-4 etc…) to add value.

We have combined figures 1-3 into one figure making sure to include the appropriate mediators that are discussed in this review. Additionally, we have added a second figure that focus the lung metastatic burden that arises from liver surgery.

 

NETs are introduced in line 104 but the section on NETs follows (line 112). Consider changing the section to indicate that NETs are discussed further below or introduce what they are in this section.

We have included a line to direct our readers to section 3 for further description of NETs and their role in tumor progression.

 

HMGB is discussed in the section on platelets and the section on NETs with different effects. Please reference back to the first section, such as “As outlined in the previous section, not only does HMGB1 bind platelets via TLR4, it also activates TLR9-dependent….”

 

We have included this reference back to the first section.

 

The section on therapeutics should reference some of the studies done in the 90s where perioperative immune stimulation with IFN-alpha or IL-2 was associated with improved immune parameters and, in a couple of studies, improved cancer outcomes. The largest of these is a phase II RCT where DFS was improved with perioperative IL-2 (Klatte 2006 British Journal of Surgery; PMID 17031403)

 

We have included a paragraph on this in the revised manuscript. Thank you for bringing this important point to our attention.

 

In line 216 you review the preclinical data for perioperative LMWH to reduce postoperative metastases. There is a clinical trial (PERIOP-01; NCT01455831) that is also asking this same question.

We have included this clinical trial in the revised manuscript

 

In the paragraph starting on line 219 you review the PERIOP-04 trial. There is no reference to the preclinical data for the trial which includes PMID: 24404430 and PMID: 29872554.

 

We have included these two key preclinical data in our revised version of the manuscript

 

In the abstract, the sentence line 15 to 18 (starting with Similarly….) seems awkward. Consider revising.

We have revised this sentence to read “Neutrophil extracellular traps (NETs), an extracellular network of DNA released by neutrophils in response to inflammation, promote the adhesion of circulating tumor cells, and growth of existing micrometastatic disease.”

 

The last statement before the concluding remarks (line 241) about PD-1 seems out of place. Please add more detail about what is known regarding PD-1 and the perioperative period or consider removing. There is nothing in the mechanism section about T cell exhaustion so talking about the therapeutic potential seems out of place.  

 

We removed this statement from the revised manuscript