Preoperative Serum Triglyceride to High-Density Lipoprotein Cholesterol Ratio Can Predict Prognosis in Non-Small Cell Lung Cancer: A Multicenter Retrospective Cohort Study

Round 1

Reviewer 1 Report

The manuscript was prepared very well. The introduction section justifies the purpose of the study. I congratulate the authors on the preparation of the manuscript

However, I have the following comments:

Introduction

·       "The use of an index that combines multiple parameters may reveal the association between cancer and lipid metabolism with greater accuracy and sensitivity [17,28,29]. " Is there any model prior to those reported in the study? Is it a novelty? If so, please justify why you do so and introduce a hypothesis.

·       Although you describe the background, please clarify the need for why this study is being conducted.

Materials and Methods

·       The methodology is perfectly described

·       Would it be possible to include following CONSORT or CARE guidelines?

Results

·       The tables/figures and the text describing them do not require any input, it is the strongest part of this study.

 

Discussion

·       What is new in this manuscript about cancer patients?

·       Include a section on strengths

·       What does this article contribute, the authors are asked to make their own assessment and include their own discussion of the results shown in the manuscript?

·       They should include some comparison with similar studies and discussions about it.

·       In the Conclusion section, state the most important outcome of your work. Do not simply summarize the points already made in the body — instead, interpret your findings at a higher level of abstraction. Show whether, or to what extent, you have succeeded in addressing the need stated in the Introduction (or objectives).

 

 

Author Response

Reviewer 1

Comments and Suggestions for Authors

The manuscript was prepared very well. The introduction section justifies the purpose of the study. I congratulate the authors on the preparation of the manuscript

 

However, I have the following comments:

 

Introduction

(1) "The use of an index that combines multiple parameters may reveal the association between cancer and lipid metabolism with greater accuracy and sensitivity [17,28,29]. " Is there any model prior to those reported in the study? Is it a novelty? If so, please justify why you do so and introduce a hypothesis.

Response: We are grateful for what you pointed out. For the first problem you mentioned, a limited number of previous studies indicated that the TG/HDL-C can work as an independent predictor and were inversely associated with the prognosis of gastric and triple negative breast cancer. Sun H et al. observed that, when compared with those of other serum lipid levels (TG, TC, LDL-C, HDL-C), TG/HDL-C harbored the highest area under curve to independently predict 5-year overall survival (OS) in patients with gastric cancer (doi:10.7150/jca.35939.). A retrospective cohort study by Dai D et al. demonstrated that TG/HDL-C is an independent predictive biomarker for OS in triple negative breast cancer patients and has an advantage over the serum TG level (doi:10.7150/jca.15776.). Previous research by Ma et al. showed that preoperative serum levels of TG and HDL-C can be independent factor to predict outcome in NSCLC patients (doi:10.1186/s12944-021-01492-y.). However, the relationship between TG/HDL-C and the prognosis of NSCLC remains unknown, which is also the original intention and the novelty of our current research. As you suggested, after consulted relevant literature, we introduced a hypothesis and explored the prognostic value of the pretreatment serum TG/HDL-C in NSCLC. Accordingly, we have added “They observed that, when compared with those of other serum lipids (TC, LDL-C, HDL-C as well as TG), TG/HDL-C showed the largest AUC in independent forecasting of 5-year OS among gastric cancer patients [28]. Retrospective cohort research by Dai D et al. also indicated TG/HDL-C as one independent predictive biomarker for OS among triple negative breast cancer patients, with an advantage over the serum TG level [29].…. According to previous research by Ma et al. [25], preoperative serum TG and HDL-C can be factors for independent outcome prediction among NSCLC patients. Whereas, the link of TG/HDL-C with NSCLC prognosis remains unknown, which is also the original intention of our current research.”. (Page2, line280-285; Page2, line288-291)

 

(2) Although you describe the background, please clarify the need for why this study is being conducted.

Response: We really appreciate your suggestion. In the abstract section, we have supplemented the need for this study “However, the correlation of preoperative serum triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) with non-small cell lung carcinoma (NSCLC) prognosis remains under exploration.”. (Pages1, line15-17) In addition, we have added the need for why this study is being conducted in the introduction section “They observed that, when compared with those of other serum lipids (TC, LDL-C, HDL-C as well as TG), TG/HDL-C showed the largest AUC in independent forecasting of 5-year OS among gastric cancer patients [28]. Retrospective cohort research by Dai D et al. also indicated TG/HDL-C as one independent predictive biomarker for OS among triple negative breast cancer patients, with an advantage over the serum TG level [29].…. According to previous research by Ma et al. [25], preoperative serum TG and HDL-C can be factors for independent outcome prediction among NSCLC patients. Whereas, the link of TG/HDL-C with NSCLC prognosis remains unknown, which is also the original intention of our current research.”. (Page2, line280-285; Page2, line288-291)

 

Materials and Methods

 

• The methodology is perfectly described

Response: We are very grateful for your affirmation of the methodology part of the manuscripts and our past work. We have improved the manuscript and made the necessary amendments according to the feedbacks of editors and reviewers.

 

• Would it be possible to include following CONSORT or CARE guidelines?

Response: Thanks for your advice. We have consulted a large number of other published literatures and found that many of them do not use CONSORT or CARE guidelines (doi:10.7150/jca.35939.; doi:10.7150/jca.15776.; doi: 10.1371/journal.pone.0143061.; doi: 10.1007/s13277-016-4793-8.), so we temporarily consider that excluding CONSORT or CARE guidelines seems to have a relatively little effect on the scientificity of this article. Based on this, we do not include it temporarily.

 

Results

 

(1) The tables/figures and the text describing them do not require any input, it is the strongest part of this study.

Response: We are very grateful for your affirmation of the results part of the manuscripts and our past work. We have made necessary amendments to the charts based on editor and reviewer feedback.

 

Discussion

 

(1) What is new in this manuscript about cancer patients?

Response: Thanks for your advice. We have provided the novel aspects of this study in the discussion section “It is noteworthy that the present study first unveiled the ability of preoperative serum TG/HDL-C level to serve as an independent prognosis factor in NSCLC. …. Moreover, our study was designed as one multi-center study, and the patients enrolled in the training and validation group were from two tertiary referral hospitals in Wuhan and Nanchang, respectively. Compared with the more common single-center retrospective studies in the past, the current study tried to avoid the potential bias to some extent.”. (Page10, line1175-1176), (Page10, line1192-1196) Moreover, based on your requirement, we have added “Besides, the present multi-center study included a larger sample size than other similar studies.” (Page10, line1196-1197)

 

(2) Include a section on strengths

Response: Thank you for your suggestion. We have provided a section on strengths in the strengths and limitations section “The strength of the present study is that the hematological parameters involved in the TG/HDL-C used to predict NSCLC prognosis are easily obtained from preoperative routine serum tests.... Moreover, our study was designed as one multi-center study, and the patients enrolled in the training and validation group were from two tertiary referral hospitals in Wuhan and Nanchang, respectively. Compared with the more common single-center retrospective studies in the past, the current study tried to avoid the potential bias to some extent. Besides, the present multi-center study included a larger sample size than other similar studies.” (Page10, line1181- line1197)

 

(3) What does this article contribute, the authors are asked to make their own assessment and include their own discussion of the results shown in the manuscript?

Response: We greatly appreciate your comment. We have added the novelty and clinical significance “It is noteworthy that the present study first unveiled the ability of preoperative serum TG/HDL-C level to serve as an independent prognosis factor in NSCLC. Clinically, TG/HDL-C is probably considered as a valuable predictive biomarker that could determine NSCLC patients with shorter OS, thus enhancing the quality of life for the special patient groups through modifying individualized clinical therapy and strengthening the surveillance.” (Page10, line1175-1180) Besides, we have supplemented the strengths of this study “The strength of the present study is that the hematological parameters involved in the TG/HDL-C used to predict NSCLC prognosis are easily obtained from preoperative routine serum tests.... Moreover, our study was designed as one multi-center study, and the patients enrolled in the training and validation group were from two tertiary referral hospitals in Wuhan and Nanchang, respectively. Compared with the more common single-center retrospective studies in the past, the current study tried to avoid the potential bias to some extent. Besides, the present multi-center study included a larger sample size than other similar studies.” (Page10, line1181- line1197)

 

(4) They should include some comparison with similar studies and discussions about it.

Response: We greatly appreciate your suggestion. We have added some comparison with similar studies “However, the cut-off value in this multicenter retrospective study (1.02) is different from that in triple negative breast cancer (0.600) and gastric cancer (1.20), which may be attributed to differences in cancer type, cancer stage and number of patients.” (Page9, line993-996) Furthermore, the consistency and differences between the current study and some previous studies were also compared in the Discussion section as follows: “A retrospective study of Ma et al. [25] proved the association of the preoperative up-regulated TG and downregulated HDL-C with unfavorable prognosis in patients who died from NSCLC. Besides, Luo et al. [26] reported that relatively high HDL-C before adjuvant chemotherapy were independent prognostic factors with longer disease-free survival for NSCLC patients. Meanwhile, Lv et al. [30] revealed that the decrease in HDL-C level can indicate liver dysfunction caused by adjuvant chemotherapy in NSCLC, which partly supported the predictive significance of TG/HDL-C for patient prognosis. Additionally, prior research has also shown that lipid imbalances, including elevated TG levels or decreased HDL-C levels enable to predict poorer prognosis in ovarian, colorectal, and breast cancer [17,31,32].” (Page9, line996- line1006)

 

(5) In the Conclusion section, state the most important outcome of your work. Do not simply summarize the points already made in the body — instead, interpret your findings at a higher level of abstraction. Show whether, or to what extent, you have succeeded in addressing the need stated in the Introduction (or objectives).

Response: We appreciate the constructive suggestion and revised the manuscript accordingly. In the conclusion section, we have interpreted our findings at a higher level of abstraction “In conclusion, our findings first evaluated and demonstrated the prognostic function of preoperative serum TG/HDL-C levels for NSCLC. Low TG/HDL-C level probably acts as one novel and effective prognostic biomarker of favorable OS in NSCLC patients. Clinically, determining lipid biomarkers associated with NSCLC prognosis can be of great importance to predict survival, guide individualized clinical therapy and improve the outcomes.” (Page11, line1291-1296)

Reviewer 2 Report

The manuscript is very interesting, the methodology is sufficient and consistent with the purpose of the study. The structure and development of the manuscript is good. The results support the discussion. However, I have the following comments.

I. Major Comments:

1. The metabolism of TG and HDL-cholesterol is dependent on the nutritional status of patients (BMI), diet and also stressful metabolic states. I suggest briefly referring to this point in the introduction.

2. Plasma levels of TG and HDL-cholesterol are closely related to hepatic metabolism, but also to diet. This point is important in various types of cancer. I suggest briefly discussing this point.

3. The results regarding TG and HDL-cholesterol are very interesting. But I suggest briefly discussing the mechanisms that would justify these results. Also, why is the same not observed with LDL-cholesterol (briefly discuss the mechanisms)? Would this be related to a proinflammatory or oxidative metabolic state?

4. Would similar results be observed in obese patients?

5. What clinical projection could this finding have? What would be the potential clinical applications? I suggest including a short paragraph about it.

II. Minor comments:

1. Improve the wording of the title. Is a title closer to completion possible?

2. Improve the writing of the objective of the study.

3. Figure 1. It is very small, it will be difficult to understand. I suggest increasing the theme and improving the resolution of the information.

4. I could not find the bioethical authorization to carry out the study.

Author Response

Reviewer 2

Comments and Suggestions for Authors

The manuscript is very interesting, the methodology is sufficient and consistent with the purpose of the study. The structure and development of the manuscript is good. The results support the discussion. However, I have the following comments.

 

1. Major Comments:

 

1. The metabolism of TG and HDL-cholesterol is dependent on the nutritional status of patients (BMI), diet and also stressful metabolic states. I suggest briefly referring to this point in the introduction.

Response: We appreciate the constructive suggestion and revised the manuscript accordingly. We have added the relevant content in the introduction section “The metabolism of serum lipids and lipoproteins, like TG and HDL-C, has strong link to the nutritional status of patients (BMI), diet and stressful metabolic states [17].” (Page2, line265-267)

 

2. Plasma levels of TG and HDL-cholesterol are closely related to hepatic metabolism, but also to diet. This point is important in various types of cancer. I suggest briefly discussing this point.

Response: Thanks for your advice. Due to plasma levels of TG and HDL-C are closely related to hepatic metabolism, diet, and medicine, on the one hand, we strictly followed the perioperative management principles for 479 subjects. In the Study population section of manuscript, we have provided “According to the perioperative management principles, every patient was asked to stop smoking and alcohol consumption within 14 days before operation, and were given light diet.” (Page3, line569-571) Because the preoperative preparation is strictly in accordance with the principles of perioperative management, the patients’ blood lipids are generally in a relatively stable state before the operation, making our results more reliable. On the other hand, we have consulted the relevant literature and added “De novo lipogenesis and exogenous lipid uptake are the two important sources of lipids for cancer cells, and lipid levels in cancer are determined by both of these fac-tors [33]. McLaughlin et al. [34] discovered the ability of TG/HDL-C to serve as one alternative biomarker of insulin resistance, which further stimulates TG production through lipolysis, and de novo lipogenesis in the liver.” (Page9, line1007-1011)

 

3. The results regarding TG and HDL-cholesterol are very interesting. But I suggest briefly discussing the mechanisms that would justify these results. Also, why is the same not observed with LDL-cholesterol (briefly discuss the mechanisms)? Would this be related to a proinflammatory or oxidative metabolic state?

Response: Thanks for your suggestion.

(1) Actually, we have provided a section on mechanisms in the discussion section “The prognostic function of TG/HDL-C in NSCLC cases is possibly attributable to the following reasons. For nearly 2 decades, a mountain of evidence has implicated both oxidative stress and chronic inflammation as pivotal factors regarding the causation of carcinogenesis and cancer progression [35-37].…Overall, higher TG level and lower HDL-C level may potentially indicate the progression of inflammation and oxidative stress in the tumor microenvironment, and thus help predict poorer clinical outcomes in cancer patients [17,22].”. (Page9, line1013-Page10, line1095)

 

(2) Due to the limitation of data collection and the absence of patient medical records, our study failed to include LDL-C data of all patients from the beginning, so we failed to explore the relationship between LDL-C and lung cancer prognosis. We have consulted relevant literature and found that elevated concentrations of LDL-C were related to poor prognoses in breast cancer, colorectal cancer, ovarian cancer and prostate cancer. (doi:10.1186/1471-2407-14-132.; PMID: 21661400; doi:10.2147/ott.S90479.). In breast cancer, LDL-C can promote the migration of breast cancer cells by decreasing the expression of various adhesion proteins, such as claudin and occluding (doi:10.1186/1476-511X-13-16.). A potential mechanism for LDL-promoted tumorigenesis could is elevated intracellular reactive oxygen species levels and subsequent cellular inflammation and damage. LDL-C can activate HER2, which increases the phosphorylation of oncogenic signaling pathways, Akt and extracellular signal-regulated kinase (ERK) (doi:10.1186/1476-511X-13-16.), Activation of these pathways by LDL-C can mediate cell proliferation in cancer. In colorectal cancer, LDL promotes the migration of colorectal cancer cells and upregulates cancer stem cells (doi:10.1159/000477890.). LDL also promotes the MAPK signaling pathway gene expression, mediated by increased expression of the p38 protein. LDL can also increase stem-ness genes such as Sox2, Oct4, Nanog, and Bmi1 in CRC cells (doi:10.1159/000477890.). High-Fat Diets may also play a role in colorectal tumorigenesis, as the use of these diets in mice models produced significant inflammatory effects (doi:10.1159/000477890.). However, the role of LDL-C in the prognosis of lung cancer, especially NSCLC, remains unclear. Therefore, more researches are needed to explore the effect of LDL-C on clinical outcomes in lung cancer patients. We will pay attention to your suggestion in our further research.

 

(3) As described in the manuscript “Overall, higher TG level and lower HDL-C level may potentially indicate the progression of inflammation and oxidative stress in the tumor microenvironment, and thus help predict poorer clinical outcomes in cancer patients [17,22].” (Page10, line1171-1173), high levels of TG/HDL-C may potentially be related to the progression of inflammation or oxidative metabolic state.

 

4. Would similar results be observed in obese patients?

Response: Thank you for your suggestion. Due to the limitations of data collection and the purpose of the study, our study did not specifically include data from obese patients from the beginning. We reviewed published studies and found that higher body mass index (BMI) has been linked to a better prognosis in patients with NSCLC, including both early-stage and advanced stages NSCLC patients (doi:10.1055/s-0035-1554964.; doi:10.3390/nu13113761.) However, there is no literature on the relationship between a biomarker (including TG, HDL-C, and TG/HDL-C) and the prognosis of obese cancer patients. You have provided a noteworthy new insight that has important clinical implications. Therefore, in accordance with your suggestion and based on previous studies, we will further explore the prognostic ability of TG/HDL in obese patients in the future further research.

 

5. What clinical projection could this finding have? What would be the potential clinical applications? I suggest including a short paragraph about it.

Response: Thanks for your advice. We have added a short paragraph about the clinical projection and clinical applications of this study in the strengths and limitations section “It is noteworthy that the present study first unveiled the ability of preoperative serum TG/HDL-C level to serve as an independent prognosis factor in NSCLC. Clinically, TG/HDL-C is probably considered as a valuable predictive biomarker that could determine NSCLC patients with shorter OS, thus enhancing the quality of life for the special patient groups through modifying individualized clinical therapy and strengthening the surveillance.…The strength of the present study is that the hematological parameters involved in the TG/HDL-C used to predict NSCLC prognosis are easily obtained from preoperative routine serum tests. Compared with traditional TNM staging system, serum lipids and lipoproteins has the characteristics of routine preoperative collection, cheap and non-invasion, which makes TG/HDL-C could be more suitable for early preoperative evaluation of prognosis in developing countries.”. (Page10, line1175-1180)” (Page10, line1181-1186)

 

1. Minor comments:

 

1. Improve the wording of the title. Is a title closer to completion possible?

Response: We appreciate your suggestion. Accordingly, we have improved the wording of the title “Preoperative serum triglyceride to high-density lipoprotein cholesterol ratio can predict prognosis in non-small cell lung cancer: A multicenter retrospective cohort study”. (Page1, line2-4)

 

2. Improve the writing of the objective of the study.

Response: We thank the reviewer for pointing out this question. We have checked and made revision accordingly “However, the correlation of preoperative serum triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) with non-small cell lung carcinoma (NSCLC) prognosis remains under exploration.” (Page1, line15-17)

 

3. Figure 1. It is very small, it will be difficult to understand. I suggest increasing the theme and improving the resolution of the information.

Response: We appreciate the helpful feedback and revised the Figures accordingly. In addition, we have resubmitted Figures in their original format for review by reviewers and further consideration for publication.

 

4. I could not find the bioethical authorization to carry out the study.

Response: We are grateful for your reminding. In the Institutional Review Board Statement section, we have added “Ethics committee belonging to Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology and First Affiliated Hospital of Nanchang University ratified the current study (reference number：TJ-IRB20220802), which was implemented with Declaration of Helsinki.”, and attached the Ethical approval proof as Supplementary materials. (Page11, line1304-1308)

Round 2

Reviewer 2 Report

The authors answered all my comments. The manuscript was improved. Therefore, the manuscript can be accepted in its present form.