The Value of C-Reactive Protein, C-Reactive Protein Kinetics and C-reactive Protein to Albumin Ratio on Prognosis in Newly Diagnosed Indolent B-cell Non-Hodgkin Lymphoma

Objective: This study aimed to determine prognostic signicance of C-reactive protein (CRP), CRP kinetics and CRP to albumin ratio (CAR) in indolent B-cell non-Hodgkin lymphoma (B-iNHL) patients. Methods: The association among these blood makers and overall survival (OS), disease-free survival (DFS), progression-free survival (PFS) were analyzed in 243 B-iNHL patients. OS, DFS and PFS were determined by Kaplan–Meier curves. Cox proportional analysis was performed to examine the prognostic signicance of clinicopathological variables. Results: Multivariate analyses identied that elevated pretreatment CRP (HR: 5.110, 95% CI: 1.904-13.717, p=0.001), post-treatment CRP (HR: 5.826, 95% CI: 1.659-20.458, p=0.006), continuously elevated CRP (HR: 6.461, 95% CI: 2.620-15.930, p<0.001) and elevated CAR (HR: 3.768, 95% CI: 1.415-10.034, p=0.008) had association with worse OS. Likewise, elevated pretreatment CRP (HR: 3.767, 95% CI: 1.777-7.984, p=0.001), post-treatment CRP (HR: 2.384, 95% CI: 1.027-5.534, p=0.043), ever-elevated CRP (HR: 2.425, 95% CI: 1.105-5.322, p=0.027), continuously elevated CRP (HR: 4.748, 95% CI: 2.114-10.660, p<0.001) and elevated CAR (HR: 2.824, 95% CI: 1.336-5.971, p=0.007) were in independent signicance with worse DFS. Elevated pretreatment CRP (HR: 2.606, 95% CI: 1.338-5.076, p=0.005), ever-elevated CRP (HR: 2.086, 95% CI: 1.040-4.188, p=0.039), continuously elevated CRP (HR: 3.296, 95% CI: 1.594-6.818, p=0.001) and elevated CAR (HR: 1.991, 95% CI: 1.021-3.882, p=0.043) were determined in independent signicance with poor PFS. The effect was statistically signicant in both follicular lymphoma (FL) and chronic lymphocytic leukemia/ small lymphocytic lymphoma (CLL/ SLL) patients. Conclusions: In conclusion, we demonstrate that CRP level, CRP kinetics and CAR could be potential prognostic indicators with independent signicance in patients with B-iNHL, also in FL and CLL/ SLL subgroups. CRP and CAR make an implementation for prognostic evaluation more easily and effectively in B-iNHL patients. and potential prognostic in B-iNHL association among pretreatment CRP level, CRP level during treatment, post-treatment CRP level, CRP kinetics, pretreatment CAR and overall survival (OS), disease-free survival (DFS), progression-free survival (PFS). prognostic signicance of CRP level, CRP kinetics and CAR in the different subgroups diseases


Introduction
Indolent B-cell non-Hodgkin lymphoma (B-iNHL) are collection of malignancies, which are characterized by slow growth that can be alleviated with treatment but cannot be cured [1]. The main subtypes include follicular lymphoma (FL), marginal zone lymphoma (MZL), chronic lymphocytic leukemia/ small lymphocytic lymphoma (CLL/ SLL) and lymphoplasmacytic lymphoma/ Waldenstroms macroglobulinemia (LPL/ WM). Disease progress or relapse is never desirable, but progress, relapse and retreatment occur on some B-iNHL patients. Early identi cation of these patients is of great signi cance for their treatment. However, limitations of existing risk strati cation tools in routine clinical use exist, it is urgent to nd new prognostic predictors. Thus, a series of studies had been carried out to search for effective alternative prognostic biomarkers [2][3][4][5].
The association between in ammation and tumors has been early presented [6]. C-reactive protein (CRP), a biomarker compounded in hepatic cells induced by pro-in ammatory cytokines, is the most commonly used clinical indicator of in ammation [7][8][9]. According to previous research, high CRP level is considered a dangerous factor for cardiovascular diseases, diabetes and chronic hepatitis B virus (HBV) in ammatory [10][11][12][13][14]. A number of previous studies have shown that elevated CRP level was associated with poor outcome in rectal cancer, hepatocellular carcinoma, lung carcinoma, melanoma, bone neoplasms, breast cancer, ovarian cancer, esophageal carcinoma and other solid tumors [15][16][17][18][19][20][21][22][23]. Regarding to hematological cancers, elevated CRP level has been reported as a poor prognostic predictor in diffuse large B-cell lymphoma, angioimmunoblastic T-cell lymphoma and CLL [24][25][26]. In addition, the prognostic value of CRP kinetics, dynamic change of CRP level throughout treatment, has been con rmed in metastatic nasopharyngeal carcinoma and renal cell carcinoma [27][28][29]. Furthermore, a novel prognostic markers involving in ammation and nutrition, CRP to albumin ratio (CAR), has been evaluated in colorectal cancer, liver cell carcinoma, lung cancer, and other solid tumors [30][31][32][33][34]. The prognostic signi cance of CRP level, CRP kinetics and CAR in B-iNHL are unclear.
This study aimed to investigate whether CRP level, CRP kinetics and CAR were potential prognostic indicators in B-iNHL patients. We studied the association among pretreatment CRP level, CRP level during treatment, post-treatment CRP level, CRP kinetics, pretreatment CAR and overall survival (OS), disease-free survival (DFS), progression-free survival (PFS). Furthermore, prognostic signi cance of CRP level, CRP kinetics and CAR in the different subgroups diseases also were investigated.

Patients
Patients who were diagnosed with B-iNHL according to the 2008 WHO classi cation and 2016 WHO classi cation between January 2012 and December 2019 at the Shandong provincial hospital in China were involved in this study [35][36]. The following types of disease were included in our analysis: FL, MZL, CLL/ SLL and LPL/ WM. Patients who were diagnosed with grade 3b FL, non-newly diagnosed, with other hematological cancers combined and had not any CRP or albumin record were excluded.

Clinical data
All clinicopathological data were obtained from medical records. Clinicopathological parameters included histologically con rmed B-iNHL, gender, age, clinical stage, international prognostic index (IPI) and treatment plan. Rai staging system was used for the clinical stage of CLL/ SLL and Ann Arbor staging system was used for FL, MZL and LPL/ WM. Laboratory data, including hemoglobin (Hb), platelet count (PLT), lactate dehydrogenase (LDH) and β2-microglobulin (β2-MG), were obtained ahead of treatment.

Follow-up
Patients were followed up each month during complete chemotherapy cycle, every 3 months after treatment rst 2 years and semiyearly thereafter. Information of death or relapse were known by referring to clinical cases or calling to their relatives for ask. OS referred to the time (in months) from diagnosis to death from any cause. DFS referred to the time (in months) from diagnosis to the palindromia of the disease being con rmed histologically or death due to disease. PFS referred to the time (in months) from diagnosis to the progression of the disease or death due to disease. This study was approved by the Biomedical Research Ethic Committee of Shandong province hospital (NO. SWYX2020-027) and informed consent was exempted based on medical records involved in this study obtained in previous clinical diagnosis and treatment.
CRP level, CRP kinetics and albumin Serum level of CRP were obtained at baseline (pretreatment CRP level), ahead of each chemotherapy (CRP level during treatment) and after all consecutive chemotherapy (post-treatment CRP level). The data were considered missing if the patient was suffering acute infection or acute episode of chronic infection. Furthermore, patients were divided into 3 cohorts based on CRP kinetics: i) continuously normal cohort: patients' CRP level were normal all the time, ii) ever-elevated cohort: patients' CRP level were ever elevated regardless any time point, iii) continuously elevated cohort: patients' CRP level were elevated all the time. In addition, serum level of albumin was obtained ahead of treatment.

Statistical analyses
First of all, receiver operating curve (ROC) analysis was used to determine the optimal cutoff value for pretreatment CRP level and CAR to distinguish between living and dead. The association between CRP level, CRP kinetics, CAR and clinicopathological parameters were evaluated by chi-square test. The association between CRP level, CRP kinetics, CAR and OS, DFS or PFS were determined by Kaplan-Meier curves and log-rank test. The signi cance of clinicopathological variables were con rmed by Cox proportional analysis in univariate and multivariate analyses. Hazard ratios (HRs) with corresponding 95% con dence intervals (CIs) were reported as relative risks. All statistical analyses were performed using IBM SPSS Statistics, Version 26. A two-sided P<0.05 was considered statistically signi cant.

Prognostic value of post-treatment CRP level
To evaluate the prognostic signi cance of post-treatment CRP level, 64 of 243 patients who had post-treatment CRP level record were involved in the analysis. Negative prognostic value of post-treatment elevated CRP level for ve-year OS (81.7% vs. 39.4%, p<0.001, log-rank test) ( Figure 2G) and DFS (56.4% vs.35.7%, p=0.020, log-rank test) ( Figure 2H) could also be found. However, elevated post-treatment CRP level was not associated with ve-year PFS (49.8% vs. 38.8%, p=0.058, log-rank test) ( Figure 2I). So we just carried out univariate and multivariate Cox regression analyses of the main prognostic factors for OS and DFS in post-treatment CRP level subgroup.

Discussion
The present study is the rst research to investigate the prognostic value of CRP level, CRP kinetics and CAR in B-iNHL patients. The reason for elevated CRP level associated with worse prognosis among cancer patients remains unknown. Previous studies had shown that in ammatory may contribute directly to tumor progression [38][39]. Zhao Sun et al. demonstrated that tumors cause in ammation, and in ammatory tumor microenvironments recruit mesenchymal stem cells (MSCs) [40]. These MSCs promote tumor growth, progression, and metastasis, leading to the formation of a vicious cycle. In ammation has also been reported promoting development and progression of cholangiocarcinoma and hepatocellular carcinoma [41][42][43]. IL-6, as the main inducers of CRP synthesis, was proved promote the progression of cholangiocarcinoma and other cancers [44][45][46][47]. Moreover, Yang et al. con rmed that CRP promoted myeloma cell proliferation under stress and protected cancer cells from being damaged by chemotherapy drugs [48]. What's more, Shengchao Xu et al. demonstrated that in ammasome inhibitors are helpful in the treatment of in ammationrelated tumors [49]. Clearly, the mechanisms of CRP regarding the progression of B-iNHL need to be clari ed in further investigations.
Fairclough et al. rstly presented the conception of CAR in 2009 [50]. Because of too much energy expenditure, cancer patients often suffer malnutrition. Because of increased catabolism and the reduce of hepatic synthesis, albumin is oppositely associated with in ammatory [51]. CAR is a novel and superior prognostic factor involving inflammatory and nutritional factors in various cancers, which was also con rmed in B-iNHL patients.
CRP and albumin are routinely tested in most hospital, which make an implementation for prognostic evaluation more easily and effectively in B-iNHL patients.
In the strati ed analyses, post-treatment elevated CRP level was considered to be not associated with PFS. This may be due to the fact that fewer patients have a record of post-treatment CRP and the cutoff value was no best distinction between progressive and non-progressive patients. In addition, post-treatment elevated CRP level was considered to be not associated with OS and DFS in FL cohort. This may be attributed to a reduced level of positive events. Besides, negative results were reported in MZL and LPL/ WM cohorts. The reason may be related to the small number of patients included in these cohorts.
Our study has some limitations. Patients with B-iNHL were recruited from a same hospital and might not be representative of the general B-iNHL. CRP is a non-speci c biomarker of in ammation. It is possible that patient's infection status was not recorded in the case, which affected the exclusion of data.
Other potential cofounders of CRP level, including body mass index, smoking and systemic treatment variables, were not included in our study.

Conclusions
We demonstrated pretreatment and post-treatment elevated CRP level can independently predict poor clinical outcomes in patients with B-iNHL. The study of CRP kinetics shows that ever and continuously and ever elevated CRP level indicate unfavorable prognosis for B-iNHL. Furthermore, pretreatment CAR as independent poor prognostic factor for clinical outcomes also were con rmed. Further investigations including large prospective studies were required to determine optimal CRP level and CAR value and to improve body in ammatory response to the malignancies. This study was approved by the Biomedical Research Ethic Committee of Shandong province hospital (NO. SWYX2020-027) and informed consent was exempted based on medical records involved in this study obtained in previous clinical diagnosis and treatment.

Consent for publication
All of the authors review the manuscript and consent for publication.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.