Abstract
Background/Aim: Previous studies have identified several inflammatory biomarkers that are useful as prognostic biomarkers for various cancer types. However, the fibrinogen-to-lymphocyte ratio (FLR) has not been addressed in head and neck squamous cell carcinoma. Here, we aimed to examine the value of pretreatment FLR as a prognostic marker in patients who received definitive radiotherapy for hypopharyngeal squamous cell carcinoma (HpSCC). Patients and Methods: This retrospective study included 95 patients treated with definitive radiotherapy for HpSCC between 2013 and 2020. The prognostic factors for progression-free (PFS) and overall (OS) survival were identified. Results: The optimal cut-off value of pretreatment FLR for discriminating PFS was 2.46. Based on this value, 57 and 38 patients were classified into groups with high and low FLR, respectively. A high FLR was significantly associated with advanced local disease and overall stage, and with the development of synchronous second primary cancer compared with a low FLR. The high FLR group had significantly lower PFS and OS rates than the low FLR group. Multivariate analysis showed that having a high pretreatment FLR was an independent prognostic factor for poorer PFS and OS [PFS: hazard ratio (HR)=2.14, 95% confidence interval (CI)=1.09-4.19, p=0.026; OS: HR=2.86, 95% CI=1.14-7.20, p=0.024]. Conclusion: The FLR has a clinical effect on PFS and OS in patients with HpSCC, suggesting that it has potential application as a prognostic factor for patients with HpSCC.
- Fibrinogen
- lymphocyte
- fibrinogen-to-lymphocyte ratio
- hypopharyngeal squamous cell carcinoma
- radiotherapy
Hypopharyngeal squamous cell carcinoma (HpSCC) is a rare malignancy that accounts for approximately 3-5% of all head and neck cancer (1, 2). The anatomical characteristics of the hypopharynx make it difficult for patients to recognize the initial symptoms of HpSCC. Thus, HpSCC is usually diagnosed at an advanced stage (3, 4). In addition, patients with HpSCC have high rates of tobacco and alcohol-related comorbidities and secondary cancer, which are often prognostic factors and lead to different outcomes among patients with HpSCC, even with the same tumor-node-metastasis (TNM) stage (5, 6). Despite progress in various treatment modalities, such as surgery, chemotherapy, and radiotherapy (RT), over the past few decades, the prognosis of patients with HpSCC remains poor, with an overall 5-year relative survival rate of 41.3% in an analysis using the Surveillance, Epidemiology, and End Results database (2). Therefore, an objective, accurate and easily measurable biomarker is urgently required to predict the prognosis of HpSCC.
Increasing evidence suggests that systemic inflammation plays an important role in cancer progression. Inflammatory molecules and agents which can be measured by routine blood examinations, such as neutrophils, monocytes, lymphocytes, platelets, fibrinogen, albumin, and C-reactive protein (CRP), and several of these markers combined, are predictors of prognosis for various types of cancer (7).
Our studies of inflammatory biomarkers in HpSCC treated with RT or concurrent chemoradiotherapy demonstrated that an elevated fibrinogen-to-lymphocyte ratio (FLR) was significantly associated with poor prognosis. The diagnostic value of the FLR as a single marker has not been reported in head and neck SCC, which is the predominant histological type (>90%) of head and neck cancer (8). We hypothesized that the FLR has potential application as a novel prognostic biomarker. The present study aimed to investigate the diagnostic efficacy of this pretreatment parameter for HpSCC treated with definitive RT.
Patients and Methods
Patients. A total of 111 consecutive patients who received definitive RT for HpSCC at Yokohama City University Medical Center between January 2013 and December 2021 were potentially eligible for inclusion in this study. The patients underwent diagnostic procedures prior to treatment, including medical history assessment, physical examination, pan-endoscopy (nasopharyngoscopy, laryngoscopy, esophagogastroscopy) with tumor biopsy, computed tomography (CT) of the area from the skull base to the diaphragm, and positron-emission tomography CT imaging. All patients were staged according to the eighth edition of the Union for International Cancer Control, TNM staging for head and neck cancer (9).
The inclusion criteria were as follows: (i) Untreated HpSCC, (ii) histologically proven SCC, and (iii) curative definitive RT. The exclusion criteria were as follows: (i) Unavailable pretreatment hematological parameters, (ii) distant metastasis at the initial visit, and (iii) treatment with extremely insufficient irradiation. Written-informed consent to participate in future retrospective studies was obtained from all the patients prior to treatment. The study was performed according to protocols approved by our Institutional Review Board (F220200008).
Treatment. All the patients received either RT or chemo-RT. The anticancer drugs concurrently combined with RT were as follows: (i) Docetaxel, cisplatin, and 5-fluorouracil; (ii) cisplatin with 5-fluorouracil; (iii) cisplatin; (iv) carboplatin; (v) tegafur and uracil; (vi) tegafur and gimeracil with oteracil; and (vii) paclitaxel.
RT was administered in a single daily fraction of 1.8 or 2.0 Gy, 5 days per week. The median radiation dose was 68.4 (range=48.0-70.2) Gy. Treatment planning was performed using a CT simulator and a three-dimensional dose calculator.
FLR and other clinical parameters. The FLR was defined as the fibrinogen level (g/l) divided by the total lymphocyte count (109/l), as previously described (10). Other potential clinical parameters obtained from the patients’ medical records or pretreatment physical and blood examinations included age, body mass index, blood cell counts, coagulation tests, and biochemical analysis. In addition to the FLR, we also examined the following nutritional and systemic inflammation parameters, which can easily be calculated from routine blood examinations: Neutrophil-to-lymphocyte ratio (neutrophil count/total lymphocyte count), lymphocyte-to-monocyte ratio (=total lymphocyte count/monocyte count), platelet-to-lymphocyte ratio (=platelet count/total lymphocyte count), CRP-to-albumin ratio (=serum CRP/serum albumin), fibrinogen-to-albumin ratio (=serum fibrinogen/serum albumin), albumin-bilirubin score {=[0.66 × log10 serum bilirubin (μmol/l)] + [−0.085×serum albumin (g/l)]}, geriatric nutritional risk index score {=[1.489× serum albumin(g/l)+ 41.7] × (present body weight/ideal body weight)}, and prognostic nutritional index score [=serum albumin (g/l) + 5 × total lymphocyte count (×109/l)] (11-14).
Statistical analyses. R version 4.0.2 (https://www.r-project.org/) was used for the statistical analyses. Progression-free survival (PFS) was defined as the time from treatment initiation to disease progression or death. Overall survival (OS) was defined as the time from treatment initiation to death from any cause. Receiver operating characteristic curve analysis was performed to calculate the area under the curve and determine a novel and optimal cut-off value suitable for predicting prognosis after RT. Fisher’s exact test was used to evaluate differences in the relationship between clinicopathological features and the FLR. The Cox proportional hazards model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) and to perform univariate and multivariate regression analyses. PFS and OS analyses were performed using the Kaplan–Meier method with the log-rank test. Values of p<0.05 were considered statistically significant.
Results
Patient characteristics. Figure 1 shows the flowchart of the patient inclusion and exclusion process in this study, and 95 patients were finally selected for the analysis. The patient characteristics are summarized in Table I. The median age of the patients was 70 (range=44-92) years, and most patients were male (93.7%). The most frequent primary site was the pyriform sinus (76.8%), and the most frequent clinical staging was TNM stage IV (53.7%). Concurrent chemotherapy was administered to 81 (85.3%) patients. Some patients developed a second primary cancer, that is, synchronous cancer, in 33 (34.7%) patients and 18 (18.9%) patients had previously had antecedent cancer. The median body mass index of the patients was 20.7 (range=12.9-28.5) kg/m2, and the median follow-up period for the survivors was 34.9 (range=3.0-108.7) months.
Flow chart of the study selection.
Association between the fibrinogen-to-lymphocyte ratio (FLR) and clinical factors.
Performance of the FLR as a prognostic marker for HpSCC. Among the potential pretreatment prognostic predictors of survival, the FLR had the highest area under the curve value for PFS of 0.647 (Figure 2A) and the second highest value for OS of 0.670 (Figure 2B).
Comparison of the area under the curve in receiver operating characteristics (AUC_ROC) analysis for pretreatment fibrinogen-to-lymphocyte ratio (FLR) and other predictors of progression-free survival (PFS) (A) and overall survival (OS) (B). ALB: Albumin; ALBI: albumin-bilirubin score; ALP: alkaline phosphatase; ALT: alanine aminotransferase; AST: aspartate aminotransferase; BMI: body mass index; BUN: blood urea nitrogen; CAR: CRP-to-albumin ratio; Cre: creatinine; CRP: C-reactive protein; eGFR: estimated glomerular filtration rate; FARI: fibrinogen-to-albumin ratio; Fib: fibrinogen; FLR: fibrinogen-to-lymphocyte ratio; GNRI: geriatric nutritional risk index; Hb: hemoglobin concentration; LDH: lactate dehydrogenase; LMR: lymphocyte-to-monocyte ratio; Lymph: lymphocyte count; Mono: monocyte count; Neu: neutrophil count; NLR: neutrophil-to-lymphocyte ratio; PLR: platelet-to-lymphocyte ratio; PLT: platelet count; PNI: prognostic nutritional index; PT-INR: international normalized ratio of prothrombin time; RBC: red blood cell count; T-Bil: total bilirubin; WBC: white blood cell count; γ-GTP: γ-glutamyl transpeptidase.
Analysis of the receiver operating characteristics curve revealed that the optimal cut-off value was 2.46 of the FLR for predicting PFS among the 95 patients, with sensitivity of 73.3% and specificity of 53.1% (Figure 3). Based on the cutoff value, 57 (60.0%) patients were categorized into the high FLR (>2.46) group and 38 (40.0%) into the low FLR (≤2.46) group.
Receiver operating characteristics curve analysis of the predictive value of fibrinogen-to-lymphocyte ratio (FLR) for progression-free survival of patients with hypopharyngeal squamous cell carcinoma treated with definitive radiotherapy. AUC: Area under the curve.
Association between the FLR and pretreatment clinical factors. The association between the FLR and pretreatment clinical factors are shown in Table I. A high FLR was significantly associated with advanced local disease and TNM stage, and with the development of synchronous second primary cancer compared with a low FLR.
Prognostic value of the FLR for patients with HpSCC. We performed a subgroup analysis to investigate the potential value of the pretreatment FLR as a prognostic factor, independent of other factors. In all patient subgroups, the group with a high FLR had a higher risk of disease progression and death after treatment compared with the low FLR group (Figure 4).
Forest plot to assess the association between the pretreatment fibrinogen-to-lymphocyte ratio (FLR) and progression-free survival (PFS) (A) and overall survival (OS) (B) of patients with hypopharyngeal squamous cell carcinoma treated with definitive radiotherapy. BMI: Body mass index.
Univariate and multivariate Cox proportional regression analyses were performed to determine the potential risk factors for PFS and OS. Multivariate analysis identified a high pretreatment FLR as an independent prognostic factor for poor PFS (HR=2.14, 95% CI=1.09-4.19; p=0.026) and OS (HR=2.86, 95% CI=1.14-7.20; p=0.024) (Table II).
Univariable and multivariable analyses of progression free survival (PFS) and overall survival (OS).
Kaplan–Meier analysis confirmed that the high FLR group had a significantly lower PFS and OS than the low FLR group using the log-rank test (p=0.012 in Figure 5A and p=0.009 in Figure 5B). The 3-year PFS rates were 43.6% and 68.5% in the groups with high and low FLR, respectively. Similarly, the corresponding 3-year OS rates were 53.5% and 85.5%, respectively. These results indicate that a high FLR is a significant pretreatment predictor of poor prognosis in patients with HpSCC.
Progression-free (A) and overall (OS) (B) survival curves according to the fibrinogen-to-lymphocyte ratio (FLR) of patients with hypopharyngeal squamous cell carcinoma treated with definitive radiotherapy.
Discussion
To the best of our knowledge, this is the first study to utilize pretreatment FLR for prognostic prediction in patients with HNSCC and HpSCC. FLR was the best potential predictor of PFS and the second best predictor of OS among all the parameters examined. We determined an FLR cut-off value of 2.46 and assigned patients to high or low FLR groups with ratios below or above the cut-off value, respectively.
In this study, a high pretreatment FLR was significantly associated with advanced local disease and TNM stage, and with the development of synchronous second primary cancer compared with a low pretreatment FLR. In addition, a high FLR was a significant independent factor predicting a poor prognosis for patients with HpSCC. Patients with a low FLR had significantly longer PFS and OS periods than those with a high FLR. In all subgroup analyses, a high FLR was associated with a higher risk of disease progression and death. Thus, the FLR, which is easily calculated from routine blood examinations, has the potential to be a useful prognostic factor for patients with HpSCC treated with definitive RT.
Angiogenesis is important for tumor growth and metastasis (15). Fibrinogen is involved in the regulation of angiogenic mechanisms and is closely associated with tumor angiogenesis, invasion, progression, and metastasis (16-18). Lymphocytes play an important role in the immune defense against cancer, and the circulating lymphocyte count is considered a surrogate marker of host immunity (19-22). In general, a low level of lymphocytes would be considered immune deficiency and to provide insufficient immunological reaction to cancer. Among lymphocytes, tumor-infiltrating lymphocytes in cancer, which reflect antitumor cell activity, are particularly important in tumor immunity (23). The presence of tumor-infiltrating lymphocytes is associated with improved survival in several cancer types (23).
Therefore, fibrinogen and lymphocytes reflect the process of tumor inflammation. Moreover, the FLR has emerged as a prognostic immune biomarker in various diseases, such as esophageal (24), gastric (10), lung (25), and colorectal (26) cancer.
In addition to the FLR, we analyzed several other prognostic markers, none of which were significantly associated with survival in patients with HpSCC compared with the FLR. The possible reasons for this include the presence of secondary primary cancer, alcohol abuse, and infectious complications in patients with HpSCC.
Transforming growth factor-β is released from cancer and the cancer microenvironment and has been suggested to play a critical role in regulating immune-cell activity and suppressing immunosurveillance, that is, inhibiting effector T-cell differentiation and dendritic cell antigen presentation, and increasing regulatory T-cells for immunosuppression (27, 28). Patients with an unfavorable prognosis might have been severely immunosuppressed owing to excessive transforming growth factor-β release from advanced locoregional disease and secondary primary cancer.
Patients with HpSCC often have a history of alcohol abuse. Genetic polymorphisms of the enzymes alcohol dehydrogenase and aldehyde dehydrogenase are associated with an increased risk of HpSCC, as well as alcohol consumption habits and the incidence of alcohol abuse (29-32). Alcohol abuse-mediated disruption of the balance between different T-cell types, aberrant T-cell activation, and promotion of T-cell apoptosis have been implicated in the reduction and dysfunction of peripheral T-cells. In addition, alcohol abuse has been suggested to cause a loss of peripheral B-cells, while inducing increased production of immunoglobulins (33). Patients with HpSCC may have alcohol-induced immunosuppression associated with their prognosis.
The inflammatory mediator interleukin-6 (IL6) plays an important role in the response to injury and infection; participates in the immune response, inflammation, and hematopoiesis; and is associated with the progression and apoptosis of several types of cancer cell (34). IL6 has been suggested as a marker of poor prognosis of cancer (35). Fibrinogen, along with CRP and serum amyloid A (SAA) protein, is produced as a result of IL6 as an acute-phase protein in hepatocytes and has also been suggested as a surrogate marker for IL6 (36-38). On the one hand, fibrinogen elevation in response to inflammatory stimuli is slower and milder than that of CRP and SAA (39); on the other, fibrinogen elevation in response to inflammatory stimuli is slower and milder than that of CRP and SAA. Patients with head and neck SCC are often exposed to transient inflammatory stimuli other than from cancer, such as lung damage induced by a history of tobacco use and infection. CRP and SAA are easily induced by factors other than cancer, and fibrinogen may be a useful biomarker that more accurately reflects the inflammatory stimuli associated with cancer.
As described above, lymphocytes and fibrinogen levels reflect the disease status of patients with HpSCC, and their combined FLR has the potential to be a useful biomarker. Although previous studies have reported that the fibrinogen and neutrophil-to-lymphocyte ratio (F-NLR), a marker similar to FLR, is a useful prognostic predictor, FLR is a continuous variable and cut-off values are easier to determine than F-NLR (40).
This current study has some limitations. Firstly, the cases included in our retrospective study were from a single center with a small sample size, which was limited and had a selection bias. secondly, different clinical stages and concurrent chemotherapy regimens might lead to heterogeneous clinical outcomes. Thirdly, insufficient data on therapy after disease progression and recurrence limited our discussion of the effect of the FLR on compliance with salvage therapy. Fourthly, insufficient information on secondary primary cancer and tobacco and alcohol history prevented a detailed analysis of their relationship to immunity, inflammation, and prognosis. Finally, all cases in our study were HpSCC, and whether the results apply to other types of head and neck SCC remain unclear. Therefore, additional prospective studies with a large cohort from multiple centers are required to confirm the reliability and applicability of this novel method using the FLR as a prognostic predictor for HNSCC.
In conclusion, the results of our study imply that the FLR is a significant prognostic factor for long-term outcomes in patients with HpSCC after definitive RT. The FLR, which is convenient and economical, can be used as a promising prospective novel biomarker for patients with HpSCC receiving definitive RT. Further studies are required to validate its reliability and application in other clinical settings.
Footnotes
Authors’ Contributions
Hiromitsu Hatakeyama and Kaname Sato made substantial contributions to conception and design. Kaname Sato, Hiromitsu Hatakeyama, Hanako Okada, Masako Kawano, Kohei Yoshida, Yamato Oki, Tatsu Kuwahara, Kazutomo Niwa, Yasuhiro Isono and Nobuhiko Oridate made substantial contributions to acquisition of data, or analysis and interpretation of data. Hiromitsu Hatakeyama and Kaname Sato were involved in drafting the article or revising it critically for important intellectual content. Hiromitsu Hatakeyama gave final approval of the version to be published.
Conflicts of Interest
The Authors declare no conflicts of interest in association with the present study.
- Received March 16, 2023.
- Revision received April 2, 2023.
- Accepted April 5, 2023.
- Copyright © 2023 The Author(s). Published by the International Institute of Anticancer Research.
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) 4.0 international license (https://creativecommons.org/licenses/by-nc-nd/4.0).
