The high levels of fibrinogen and platelets are associated with poor survival in nephroblastoma in children

Introduction

Nephroblastoma, also known as Wilms’ tumor, is the most common malignant tumor of the urinary system in children (1). It is an embryonal kidney tumor that is slightly more prevalent among girls. It accounts for approximately 6% of childhood (0–18 years) cancer cases (2). According to the Children’s Oncology Group (COG), nephroblastoma is classified into five stages, ranging from stage I to stage V (3). The combination of surgery with chemoradiotherapy has become the mainstream treatment approach (4). However, the survival rate of nephroblastoma patients remains unsatisfactory. According to reports, the 5-year survival rate of nephroblastoma patients was approximately 85%, while the 4-year relapse-free survival estimates for patients with unfavorable pathological typing in stage II, III, or IV disease were 40.0%, 33.3%, and 0%, respectively (5). Therefore, it is particularly important to analyze the factors that affect the prognosis of patients with nephroblastoma following surgery.

Tumor cells can form large aggregates through fibrinogen and platelet. These aggregates are wrapped by platelets and fibrinogen, allowing them to evade the killing effect of the human immune system (6). Previous studies have demonstrated a relationship between platelets, cancer, and the abundance of activated platelets in the microenvironment of various types of tumors, including ovarian cancer and oesophageal cancer (6-8). Hyperfibrinogenemia was observed in various malignant tumors, including colorectal cancer, lung cancer, endometrial cancer, and pancreatic cancer, and often indicated a poor prognosis (9-12).

However, the prognostic value of fibrinogen and platelet in nephroblastoma has not been clearly established. Therefore, this study aimed to investigate the relationship between fibrinogen and platelet levels and nephroblastoma children’ clinical parameters and overall survival. We present this article in accordance with the TRIPOD reporting checklist (available at https://tcr.amegroups.com/article/view/10.21037/tcr-24-1203/rc).

Methods

Ethical statement

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study received formal approval from the Ethics Committee at The Second People’s Hospital of Lianyungang (January 2024; approval No. 20240003). All participating hospitals were informed and agreed the study. Prior to commencing the study, all legal guardians of the participating children were thoroughly informed about the entire research and provided their consent through signed informed consent forms.

Patients and study design

Between January 2004 and January 2018, The Second People’s Hospital of Lianyungang, Children’s Hospital of Hangzhou, Children’s Hospital of Xuzhou, and The First People’s Hospital of Lianyungang admitted 129 nephroblastoma children and 129 non-tumor children who underwent high ligation of the hernial sac. All patients were under 18 years old and underwent surgical treatment after being definitively diagnosed with nephroblastoma through clinical imaging data. Their pathological results confirmed the diagnosis of nephroblastoma. Depending on different stages, surgical conditions, and pathological conditions, chemotherapy was administered 3–5 days after surgery, and radiotherapy was performed within 1–2 weeks after surgery. For each individual, we recorded various clinical parameters, including age, gender, laterality, COG stage, pathological typing, hematuresis, hypertension, venous thrombosis, fibrinogen levels, and platelet count. Post-surgery, we initiated a follow-up protocol for all nephroblastoma patients, which involved either telephone check-ins or outpatient visits.

Inclusion and exclusion criteria

Patients were eligible for inclusion in the present study if they met the following criteria: (I) were diagnosed with nephroblastoma and were under 18 years of age; (II) expressed willingness to participate and provided written informed consent; (III) had complete clinical parameter records available; and (IV) were able to commit to the full follow-up process. Exclusion criteria encompassed the following: (I) patients who did not undergo surgery or lacked pathological records; (II) those with incomplete clinical parameter records; (III) individuals unable to complete the required follow-up; (IV) patients with concomitant other tumors; and (V) patients older than 18 were excluded.

Sample size

Using our pilot data as a foundation, we estimated the sample size using the PASS11 software (NCSS, LLC, Kaysville, Utah, USA) with a study power of 80% and a significance level of 5%. The software’s calculations suggested a minimum sample size of 56 patients per group.

Statistical analysis

Statistical analyses for this study were conducted using SPSS 22.0 (IBM Corp., Armonk, NY, USA) and R version 4.0.2 (available at https://www.r-project.org/). Categorical variables were represented by frequencies and percentages, while continuous variables were summarized using the median and interquartile range. To assess associations between categorical variables, we employed Pearson’s χ² test or Fisher’s exact test. For numerical variables, the Mann-Whitney U test was utilized. Kaplan-Meier curves were generated to estimate recurrence-free survival probabilities, and the log-rank test was used to compare survival curves. To identify predictors of survival, multivariate Cox regression analysis was performed.

Additionally, a nomogram model, as described in (13), was constructed to predict the prognosis of nephroblastoma. Based on this model, risk scores were calculated and patients were stratified into high-risk and low-risk groups. To evaluate the prognostic accuracy of the nomogram model, internal validation was conducted using the concordance index (C-index) and calibration curve. The C-index was determined by calculating the area under the receiver operating characteristic (ROC) curve. The calibration plot method was employed to assess the model’s calibration, involving a comparison between predicted event incidence and actual incidence.

Furthermore, external validation was performed by applying the nomogram to patients in the testing cohort. Decision curve analysis (DCA) was also conducted to assess the clinical utility and benefits of the prediction model. Statistical significance was set at a P value of less than 0.05 for all tests.

Results

Preoperative fibrinogen and platelet levels in pediatric nephroblastoma group compared to non-tumor group

Upon testing indicators in both the nephroblastoma and non-tumor group, it was observed that fibrinogen levels (with a mean concentration of 4.06±1.64 g/L) were notably elevated in the nephroblastoma group compared to non-tumor group (whose mean concentration was 3.55±1.05 g/L). This difference proved to be statistically significant, with a P value of 0.01. As for platelet levels, although they were higher in the cancer group (mean concentration 277.13±138.26 ×10⁹/L) than in the non-tumor group (mean concentration 259.31±106.24 ×10⁹/L), this increase did not reach statistical significance, yielding a P value of 0.32 (Table 1).

Preoperative fibrinogen and platelet levels have been identified as independent predictors in children with nephroblastoma

A total of 57 and 48 children with nephroblastoma exhibited preoperative fibrinogen and platelet levels surpassing the standard thresholds, respectively. In our multivariate Cox regression analyses, aimed at predicting the 5-year overall survival rate and adjusted for various factors such as age, gender, laterality, COG stage, pathological typing, hematuresis, hypertension, and venous thrombosis, we found that the 5-year overall survival rate was independently linked to COG stage, pathological typing, venous thrombosis, as well as fibrinogen and platelet levels (Table 2).

The correlation between fibrinogen and platelet levels and the clinical pathological parameters in children afflicted with nephroblastoma has been thoroughly examined

The preoperative fibrinogen normal group was juxtaposed against the high-level group, revealing distinct differences. Additionally, a notable correlation was observed between fibrinogen levels and various clinical parameters, including COG stage, pathological typing, hematuresis, hypertension, and venous thrombosis, as depicted in Figure 1. Furthermore, a statistically significant variation in mean platelet levels was identified across different COG stages, pathological typings, hematuresis occurrences, and the presence of venous thrombosis, as illustrated in Figure 2.

Figure 1 The relationship between fibrinogen levels and clinical pathological parameters in children with nephroblastoma. (A) Age; (B) gender; (C) laterality; (D) COG stage; (E) COG stage (I–II vs. III–IV); (F) pathological typing; (G) hematuresis; (H) hypertension; (I) venous thrombosis. ANOVA, analysis of variance; COG, Children’s Oncology Group; FH, favorable histology; UH, unfavorable histology.

Figure 2 The relationship between platelet levels and clinical pathological parameters in children with nephroblastoma. (A) Age; (B) gender; (C) laterality; (D) COG stage; (E) COG stage (I–II vs. III–IV); (F) pathological typing; (G) hematuresis; (H) hypertension; (I) venous thrombosis. ANOVA, analysis of variance; COG, Children’s Oncology Group; FH, favorable histology; UH, unfavorable histology.

Preoperative elevations in fibrinogen and platelet levels suggested that children with nephroblastoma may have a shorter 5-year overall survival rate and a poorer prognosis

After conducting Kaplan-Meier survival analysis for 5-year overall survival, it was observed that there were no significant differences in 5-year overall survival rates among children with nephroblastoma based on factors such as age, primary tumor site, sex, and hypertension (Figure 3A-3D). However, statistically significant differences were found in survival rates when considering pathological typing, COG stage, hematuresis, and venous thrombosis (Figure 3E-3H). Furthermore, elevated levels of fibrinogen and platelet were associated with shorter 5-year overall survival and a poorer prognosis in children with nephroblastoma (Figure 3I,3J).

Figure 3 Five-year survival Kaplan-Meier curves for children with nephroblastoma. (A) Age; (B) laterality; (C) gender; (D) hypertension; (E) pathological typing; (F) COG stage; (G) hematuresis; (H) venous thrombosis; (I) fibrinogen levels; (J) platelet levels. COG, Children’s Oncology Group; FH, favorable histology; UH, unfavorable histology.

Construction and validation of a prognostic nomogram

The nomogram is an excellent visualization technique for quantifying the outcomes of Cox regression analysis. We integrated all relevant clinicopathological factors to construct a nomogram aimed at predicting the likelihood of overall survival at 1, 5, and 10 years for patients with nephroblastoma (Figure 4A). Following the development of these nomograms, we employed a range of indicators for internal validation. Utilizing the model, we derived risk scores and illustrated the survival durations for both high-risk and low-risk groups in Figure 4B. The nomogram model exhibited strong predictive performance, with area under the curve values reaching 0.973, 0.932, and 0.941 for overall survival at 1, 5, and 10 years, respectively (Figure 4C-4E). When we compared the predicted and actual probabilities of overall survival at these time points, the calibration plots revealed a close alignment between the predicted risk curve and the ideal curve, highlighting the model’s reliability (Figure 4F-4H). DCA further confirmed the substantial net benefits of this model for nephroblastoma children (Figure 4I-4K).

Figure 4 Construction and validation of a prognostic nomogram. (A) Nomogram for 1-, 5-, and 10-year overall survival rate of children with nephroblastoma; (B) the survival time in high-risk and low-risk groups for the 129 patients, green bar: children in low-risk group, red bar: children in high-risk group; (C-E) time dependent ROC curve analysis of the nomogram for the 1, 5, and 10 years; (F-H) calibration plot of a nomogram for 1-year, 5-year and 10-year overall survival rate of children with nephroblastoma; (I-K) the decision curve analysis of the nomogram at 1-year, 5-year, and 10-year. ROC, receiver operating characteristic; COG, Children’s Oncology Group; FH, favorable histology; UH, unfavorable histology; AUC, area under the curve.

For external validation, we randomly divided all patients into training and testing cohorts. Importantly, the statistical analysis of all variables in both cohorts yielded P values greater than 0.05 (Table 3), indicating robustness. In the testing cohort, the nomogram model maintained its predictive accuracy, with area under the curve values of 0.964, 0.979, and 0.977 for overall survival at 1, 5, and 10 years, respectively (Figure 5A-5C). Calibration plots demonstrated close agreement between the predicted and actual survival rates at these time points (Figure 5D-5F). DCA again verified the model’s significant net benefits for nephroblastoma patients (Figure 5G-5I). Taken together, these findings underscore the nomogram’s accuracy and utility as a predictive tool for overall survival in nephroblastoma children.

Figure 5 External validation of the prognostic nomogram. (A-C) Time dependent ROC curve analysis of the nomogram for the 1, 5, and 10 years in testing cohort; (D-F) calibration plot of a nomogram for 1-year, 5-year and 10-year overall survival rate of children with nephroblastoma in testing cohort; (G-I) the decision curve analysis of the nomogram in the testing cohort at 1-year, 5-year, and 10-year. ROC, receiver operating characteristic; AUC, area under the curve.

Discussion

Fibrinogen, a mucin-based protein synthesized by liver cells, plays a pivotal role in the blood coagulation process (14). The normal concentration range of fibrinogen in humans is between 2 to 4 g/L (15). In clinical settings, fibrinogen is frequently administered to patients who have been diagnosed with coagulopathy or other hematological disorders (16). Furthermore, fibrinogen has been reported to possess predictive capabilities with regards to survival outcomes in some other cancer patients (6,9,10). In children with nephroblastoma, a significant elevation of fibrinogen was observed, which significantly increases the likelihood of cancer emboli formation. Consequently, this elevation also heightens the risk of blood metastasis and mortality in these cancer patients. Simultaneously, an abnormally elevated level of fibrinogen leads to a profound disruption of the fibrinolytic system, activating fibrinolytic substances that hydrolyze both the inner membrane and the basement membrane of blood vessels (12). This process ultimately facilitates the dissemination of cancer cells. The plasma fibrinogen concentration observed in children with nephroblastoma in our study was notably elevated compared to that of the healthy population, aligning with findings from previous research (6,12,17). Studies have demonstrated that the blood coagulation index in the venous blood of cancer patients is markedly elevated compared to the corresponding indicators in peripheral venous blood, thus confirming the significant impact of cancer tissues on the coagulation system (8,16).

Previous studies have not reported any association between fibrinogen and nephroblastoma. Our findings revealed a progressive increase in plasma fibrinogen levels correlating with advanced pathological typing, higher COG stages, and the presence of hematuresis, hypertension, and venous thrombosis. In a previous study analyzing 305 cases of colorectal cancer, the results indicated a statistically significant difference in mean plasma fibrinogen levels across various tumor node metastasis scores. Additionally, as the postoperative pathological stage progressed, a corresponding increase in the average plasma fibrinogen level was observed (9). In this study, 129 children with nephroblastoma underwent radical resection, and the subsequent results revealed statistically significant differences in plasma fibrinogen levels between stages I–II and III–IV. This finding implies that plasma fibrinogen levels elevate as the disease progresses, allowing for a preliminary assessment of the patient’s condition prior to surgery. Furthermore, an extended survival analysis demonstrated an association between plasma fibrinogen levels and overall survival, indicating that patients with pre-existing hyperfibrinogenemia had reduced overall survival, lower survival rates, and a poorer prognosis.

Platelets play a crucial role in the process of blood clotting as well (18). Previous studies have shown a correlation between platelets, cancer, and the elevated presence of activated platelets within the microenvironments of various tumor types, including ovarian and esophageal cancers (6-8). After conducting our investigation, we observed that the platelet counts in children with nephroblastoma were not notably elevated compared to healthy children. This finding contradicts previous literature reports, which could potentially be attributed to disparities among various tumor types. Our study revealed a significant correlation between plasma platelet levels in children with nephroblastoma and factors such as pathological typing, COG stage, and venous thrombosis. Interestingly, unlike fibrinogen, there was no apparent association with hypertension. The underlying reasons for these observations require further exploration. Additionally, our survival analysis indicated that elevated plasma platelet levels were associated with poorer overall survival outcomes. It was found that both the fibrinogen and platelet levels can affect the prognosis of nephroblastoma children. Therefore, we built a nomogram model to predictive the prognosis of nephroblastoma children. By internal and external verification, it was found that this model has good predictive value.

While this research offers a relatively comprehensive outlook on fibrinogen and platelet levels in children with nephroblastoma, it is important to acknowledge its limitations. The study has a retrospective design and a relatively small sample size drawn from four institutions. Furthermore, the primary research institutions are situated in the economically underdeveloped region of northern Jiangsu, and the extended time frame of the study contributed to an overall 5-year survival rate that is lower than what is currently reported in the literature. Lastly, we did not analyze the correlations with C-reactive protein, lactate dehydrogenase, uremic acid, and volume of the tumor in the present study. In future research, we intend to address this shortcoming by further investigating these correlations in order to gain more valuable insights and discoveries.

Conclusions

Fibrinogen and platelet levels in children with nephroblastoma exhibit a noteworthy correlation with pathological typing, COG stage, and venous thrombosis, thereby influencing the prognosis of these young patients. By incorporating these independent prognostic variables, nomograms were developed to offer precise and user-friendly predictions of overall survival for children with nephroblastoma. These nomograms serve as invaluable aids for clinicians, enabling them to assess individualized risks and implement the most appropriate therapeutic interventions. However, although platelet levels were observed to be lower in the non-tumor group compared to the group of children with nephroblastoma, the difference did not reach statistical significance, suggesting that further research with a larger sample size may be necessary to confirm this observation.

Acknowledgments

Funding: The study was supported by Lianyungang City Maternal and Child Health Research Project (No. F202319).

Footnote

Reporting Checklist: The authors have completed the TRIPOD reporting checklist. Available at https://tcr.amegroups.com/article/view/10.21037/tcr-24-1203/rc

Data Sharing Statement: Available at https://tcr.amegroups.com/article/view/10.21037/tcr-24-1203/dss

Peer Review File: Available at https://tcr.amegroups.com/article/view/10.21037/tcr-24-1203/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tcr.amegroups.com/article/view/10.21037/tcr-24-1203/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The present study was approved by the Ethics Committee of The Second People’s Hospital of Lianyungang (January 2024; approval No. 20240003). All participating hospitals were informed and agreed the study. Written informed consent was obtained from all legal guardians of the children prior to their participation in the study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Haase GM, Ritchey ML. Nephroblastoma. Semin Pediatr Surg 1997;6:11-6. [PubMed]
2. Breslow N, Olshan A, Beckwith JB, et al. Epidemiology of Wilms tumor. Med Pediatr Oncol 1993;21:172-81. [Crossref] [PubMed]
3. Vujanić GM, Parsons LN, D'Hooghe E, et al. Pathology of Wilms' tumour in International Society of Paediatric Oncology (SIOP) and Children's oncology group (COG) renal tumour studies: Similarities and differences. Histopathology 2022;80:1026-37. [Crossref] [PubMed]
4. Pietras W. Advances and changes in the treatment of children with nephroblastoma. Adv Clin Exp Med 2012;21:809-20. [PubMed]
5. Daw NC, Chi YY, Kalapurakal JA, et al. Activity of Vincristine and Irinotecan in Diffuse Anaplastic Wilms Tumor and Therapy Outcomes of Stage II to IV Disease: Results of the Children's Oncology Group AREN0321 Study. J Clin Oncol 2020;38:1558-68. [Crossref] [PubMed]
6. Stone RL, Nick AM, McNeish IA, et al. Paraneoplastic thrombocytosis in ovarian cancer. N Engl J Med 2012;366:610-8. [Crossref] [PubMed]
7. Elaskalani O, Berndt MC, Falasca M, et al. Targeting Platelets for the Treatment of Cancer. Cancers (Basel) 2017;9:94. [Crossref] [PubMed]
8. Shimada H, Oohira G, Okazumi S, et al. Thrombocytosis associated with poor prognosis in patients with esophageal carcinoma. J Am Coll Surg 2004;198:737-41. [Crossref] [PubMed]
9. Yamashita H, Kitayama J, Taguri M, et al. Effect of preoperative hyperfibrinogenemia on recurrence of colorectal cancer without a systemic inflammatory response. World J Surg 2009;33:1298-305. [Crossref] [PubMed]
10. Guo Q, Zhang B, Dong X, et al. Elevated levels of plasma fibrinogen in patients with pancreatic cancer: possible role of a distant metastasis predictor. Pancreas 2009;38:e75-9. [Crossref] [PubMed]
11. Ghezzi F, Cromi A, Siesto G, et al. Prognostic significance of preoperative plasma fibrinogen in endometrial cancer. Gynecol Oncol 2010;119:309-13. [Crossref] [PubMed]
12. Jones JM, McGonigle NC, McAnespie M, et al. Plasma fibrinogen and serum C-reactive protein are associated with non-small cell lung cancer. Lung Cancer 2006;53:97-101. [Crossref] [PubMed]
13. Balachandran VP, Gonen M, Smith JJ, et al. Nomograms in oncology: more than meets the eye. Lancet Oncol 2015;16:e173-80. [Crossref] [PubMed]
14. Drouet L. Bal dit Sollier C. Is fibrinogen a predictor or a marker of the risk of cardiovascular events? Therapie 2005;60:125-36. [Crossref] [PubMed]
15. Lebreton A, Casini A. Diagnosis of congenital fibrinogen disorders. Ann Biol Clin (Paris) 2016;74:405-12. [Crossref] [PubMed]
16. Chapin JC, Hajjar KA. Fibrinolysis and the control of blood coagulation. Blood Rev 2015;29:17-24. [Crossref] [PubMed]
17. Zhang Y, Liu N, Liu C, et al. High Fibrinogen and Platelets Correlate with Poor Survival in Gastric Cancer Patients. Ann Clin Lab Sci 2020;50:457-62. [PubMed]
18. Thon JN, Italiano JE. Platelets: production, morphology and ultrastructure. Handb Exp Pharmacol 2012;3-22. [Crossref] [PubMed]