A Novel Score Combining Magnetic Resonance Spectroscopy Parameters and Systemic Immune-inammation Index Improves Prognosis Prediction in Non-small-cell Lung Cancer With Brain Metastases

Background: The aim of this study was to evaluate the signicance of combination of the magnetic resonance spectroscopy (MRS) parameters and systemic immune-inammation (SII) in patients with brain metastases (BM) from non-small-cell lung cancer (NSCLC) treated with stereotactic radiotherapy. Methods: 118 NSCLC patients with BM who treated with stereotactic radiotherapy were retrospectively enrolled into this study. All patients underwent MRS and blood samples test for SII analysis before the initiation of stereotactic radiotherapy. The correlation between the parameters of MRS and SII level were assessed using the spearman correlation coecient. The cut-off values for the parameters of MRS, SII and clinical laboratory variables were dened by the receiver operating characteristic (ROC) curve analysis to quantify these predictive value. The prognostic factors of overall survival (OS) and progression-free survival (PFS) curves were assessed using Kaplan-Meier and Cox proportional hazards models. Results: The median follow-up time was 25 months (range, 12-49months). The optimal cutoff point for the cho/cr and SII were 1.50 and 480, respectively. The cho/cr was negatively correlated with SII (rs = 0.164, P = 0.075), but there was a trend. C-SII score was established by combining cho/cr and SII. Patients with both an elevated cho/cr (> 1.50) and an elevated SII (> 480) were given a C-SII score of 2, and patients with one or neither were given a C-SII score of 1 or 0, respectively. Kaplan–Meier analysis showed that the C-SII score of 2 was signicantly linked with poor OS and PFS (P < 0.001, P < 0.001). In the Cox proportional hazards model, the C-SII score independently predicted OS [hazard ratio (HR), 1.749; 95% CI, 1.176-2.601; P = 0.006] and PFS (HR, 2.472; 95% CI, 1.624-3.763; P < 0.001). Conclusion: C-SII score was more 1.749; 95% CI, 1.176–2.601; P = 0.006) and PFS (HR, 2.472; 95% CI, 1.624–3.763; P < 0.001).


Background
Lung cancer is the most common cancer and the leading cause of cancer-related mortality in China. 1 Nonsmall-cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases and NSCLC has a high predilection to metastasize to brain. 2 Brain metastasis (BM) occurs in approximately 20-40% of patients with NSCLC, and that has become an important factor affecting the clinical outcomes of patients despite active treatments. 3,4 Radiation therapy include stereotactic radiotherapy and whole brain radiation treatment. Stereotactic radiotherapy has shown advantages over whole-brain radiotherapy as the effective treatment of choice for BM patients because of excellent local control and minimal toxicity. [5][6][7][8][9] However, median survival time is < 12 months and a low quality of life in patients with BM, which poses a major challenge for NSCLC patients with BM. 10 Reliable prognostic indicators must be identi ed to look for a better treatment choice and assess patient prognosis.
Abnormal metabolism in tumors tissue has been reached consensus and this study of metabolomics continues to provide new insight into biological behavior of the tumor. 11 Advanced magnetic resonance spectroscopy (MRS) technique, can apply to various clinical questions and evaluate cellular metabolism biochemical composition. MRS technique provides the principal metabolite biochemical composition such as N-acetyl-aspartate (NAA), choline (cho) and creatine (cr). The cho re ects synthesis and metabolism cell membranes and turnover of the cell membrane during breakdown. 12 Cr re ects the energy metabolism of the brain tissue cell, which are constant in normal brain tissue. 13 NAA, a brain tissue neuronal marker, is reduced in the development of brain tumors. 13 MRS parameters have widely been shown to be capable of identifying the biology of tumor metabolism, and can monitor the treatment effect or tumor progression. 14,15 Our primary study have shown that cho/cr has been independently veri ed as useful predictors in the prognosis of NSCLC patients. 16 However, the occurrence of tumor is a comprehensive result of various systemic disorders, and its characteristics cannot be accurately predicted simply from one aspect. Cancer-related in ammation is an necessary component of the tumor microenvironment, and in ammatory cells may play a critical role in the development of malignancies. 17 Furthermore, systemic immune-in ammation involves metabolic biochemical mechanisms where cancer cells express immune-in ammatory cytokines, potentially re ecting the biological activity of tumor cells.
These theories continue to enhance our understanding of tumors and in ammation. In the clinics, systemic immune-in ammation index (SII), derived from neutrophil (N), lymphocyte (L), and platelet (P) in peripheral blood, has been deeply investigated in many malignancies. SII has become a reliable biomarker to re ect the immune and in ammation status of host and has been used as a prognostic index in multiple malignant cancers, including NSCLC. 18-22 MRS represent the biological activity of cellular metabolism, while SII re ects immune-in ammation status, whereas both have been independently veri ed as useful predictors in the prognosis of NSCLC patients. However, the clinical data focusing on the predictive value of combination of the MRS and SII for BM in NSCLC patients treated with stereotactic radiotherapy remains unknown.
This study was performed to explore the prognostic value of C-SII score for BM in NSCLC patients treated with stereotactic radiotherapy and aimed to provide appropriate and individualized therapy in clinical treatment.

Study design
Between January 2014 and December 2017, the 118 patients with histologically con rmed NSCLC receiving stereotactic radiotherapy at Rizhao Center Hospital were retrospectively reviewed. The clinical pathological characteristics of age, gender, Karnofsky performance score, patient histology, number of BMs and TNM stage were collected for patients by the medical records. The MRS metabolism composition and immune-in ammatory parameters were obtained from the peripheral blood and from MRS, respectively. The inclusion criteria were: (i) Age > 18 years old; (ii) biopsy histological con rmation of NSCLC; (iii) Eastern Cooperative Oncology Group (ECOG) ranged from 0 to 2 scores; (iv) MRS imaging was obtained before treatment and no contraindications; (v) the number of BM ≤ 3; and (vi) no hematological disorders. The speci c patient ow chart is shown in Fig. 1.

Radiation treatment
Enhanced computed tomography (CT) scans (Philips Brilliance Big Bore CT) imaging were acquired and fused with a T1-weighted post-gadolinium MRI scan within 7 days of CT localization. The gross tumor volume (GTV) is accurately delineated by the identi cation of fusion images on the planning system, or 18F uorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). At the same time, we have mapped out the critical organ structures (OAR), including the brain stem, left eye, right eye, left optic nerve, right optic nerve, lens and optic chiasm. The range of stereotactic radiotherapy doses used was 40-60 Gy. All radiation plans were created with arcs of 6-MV photons. (Fig. 2) Patients were given corresponding dehydration therapy to reduce brain edema during treatment.

MRS analysis
The brain scan sequence (MRI plain scanning, enhanced MRI scan and MRS scan ) was performed by 3.0 T clinical scanner magnetic resonance machine (Philips Healthcare, USA). We used point-resolved spectroscopic (PRESS) to perform multivoxel MRS sequence scanning and determined the region of interest (ROI) by three clinicians and radiologists. Normal brain tissue at the opposite side of the tumor lesion was selected as the reference area. 1

Peripheral blood sample analysis
We collected peripheral venous blood from the patient within 7 days before stereotactic radiotherapy. We strictly grasp the inclusion criteria and perform related index analysis. SII was calculated using the following formula: SII = P*N/L, which is based on platelet (P), neutrophil (N), and lymphocyte (L) counts.
NLR was de ned as the absolute neutrophil count divided by the absolute lymphocyte count. PLR was de ned as the absolute platelet count divided by the absolute lymphocyte count.
De nition of C-SII score Based on the optimal cutoff value, cho/cr and SII was split into low and high groups, respectively. In this study, we constructed a novel prognostic C-SII score system, which included both cho/cr and SII. We assigned a score of 0-2 to the cho/cr (low and high) and the SII (low and high). Patients were classi ed into three subgroups: low cho/cr and low SII group (score = 0), low cho/cr or low SII group (score = 1), and high cho/cr and high SII group (score = 2).

Statistical analysis
The predictive value of the MRS and peripheral blood parameters was assessed by calculating the area under the ROC curve (AUC). A ROC curve was generated to obtain the cho, cr, NAA, Cho/Cr, cho/NAA, N, P, L, SII, NLR and PLR cut-off values. Spearman coe cient test was performed to explore correlations between cho/cr and SII. Survival curves were analyzed to assess the survival time distribution by the Kaplan-Meier method and compared using the log-rank test to test the signi cance of OS and PFS among the different prognostic groups. Univariate and multivariate analysis logistic regression analyzes were used to determine independent prognostic factors. Two-sided P values < 0.05 were considered statistically signi cant. All analyses were conducted by using SPSS v19.0 software (SPSS, Inc., Chicago, IL, USA) and GraphPad Prism 5 software (GraphPad, San Diego, CA, USA).

Clinicopathological characteristics of patients
As shown in Table 1, a total of 118 patients were enrolled in this retrospective study. Ages ranged from 52 to 71 years (median, 59 years). Most patients (54.2%) were female and the majority of them (74.6%) was adenocarcinoma. The ndings showed 72 (61.0%) with 1 brain metastases and 88(74.6) patients with neurologic symptoms. Regarding staging, 75 patients (63.6%) had T1-T2 stage and there were (31.4%) patients with N2 and N3 stage tumors. After a median follow up of 25 months (range 15-49 months), 69 of the 118 (58.5%) patients suffered recurrence and metastasis, and 66 (55.9%) patients died.  Table 2 presents the results of quantitative parameters of MRS and immune-in ammatory. We observed a negative correlation between cho/cr and SII, but there was a positive trend (P = 0.075; Spearman's correlation coe cient, rs = 0.164). (Fig. 5)

Survival analysis
After median 25 months' follow-up, OS (median OS 23 vs. 18 months) and PFS (median PFS 13 vs. 9 months) in the low cho/cr group as compared with the high cho/cr were signi cantly prolonged. In particular, patients with high SII showed a shorter OS (median OS 18 vs. 20 months) and PFS (median PFS 9 vs. 11.5 months). (Fig. 6 ) The median OS in patients with C-SII score 2 was signi cantly lower than the OS in patients with C-SII score 1 and C-SII score 0 (18 vs. 18 vs. 23 months; P < 0.001) (Fig. 7A).
Univariate and multivariate Cox regression analyses were performed to explore the factors affecting survival for in this study. The univariate analysis revealed that age (P = 0.022), smoke (P = 0.023) and KPS (P = 0.003) were signi cantly associated with OS, KPS (P = 0.014) and patient histology (P = 0.003) were signi cantly associated with PFS. In terms of MRS and peripheral blood parameters, PLR (P = 0.033, P = 0.006), SII(P = 0.001, P = 0.002 ) and Cho/Cr(P = 0.007, P < 0.001 ) were positively associated with OS Page 9/25 and PFS. We found no signi cant association of survival with number of BMs, maximum diameter, neurologic symptoms, and TNM stage. (

Discussion
Reliable prognostic prediction score system is crucial in risk strati cation for patients and adjusting appropriate treatment strategy for NSCLC with BM. In the present study, we investigated the utility of cho/cr and SII and C-SII score on prognosis in NSCLC patients. The results showed that C-SII score is independent predictors of OS and PFS among NSCLC patients with BM.
In recent years, stereotactic radiotherapy is used to treat limited numbers of BM, since this therapy is less invasive than drug and surgical resection with better local control. 23,24 Therefore, the use of stereotactic radiotherapy is recommended to further control BM risk. 25 At present, various blood indicators have been evaluated the prognosis role of NSCLC patients with BM, such as Neuron-speci c enolase (NSE), 26 Carcinoembryonic antigen (CEA) 27 and Lung-molGPA. 28 However, there are no more reliable predictors that can re ect different tumor biological behavior. Hence, searching for accurate prognostic factors is of great clinical application value.
The occurrence of tumor is often accompanied by changes in metabolism biochemical composition.
MRS is a noninvasive and sensitive imaging method that allows researchers to measure and visualize metabolism biochemical information from brain tumor tissues. 29 Increasing evidence have indicated that MRS can identify tumor active region and enhance more individualized response-based treatment in High-grade Glioma. 15 An ongoing effort at Tehran University of Medical Sciences has shown that MRS parameters can improve the accuracy of predictive nomograms to assess the risk of biochemical recurrence after radical prostatectomy in prostate cancer. 30 More comprehensive understanding the biochemical composition changes in metabolites for tumors is more urgent. The typical MRS metabolic abnormalities of BM often include increased cho, decreased NAA and cr. Minicozzi et al observed in thirtysix head and neck cancer cases that cho/cr is signi cantly elevated in the group with poor response. 14 Fink et al found that multi-voxel MRS cho/cr peak-area shows great advantage for distinguishing glioma recurrence. 31 Negendank and colleagues conducted a co-operative study with 15 clinical research centers and con rmed that the cho was higher in glial tumors than in non-involved brain tissues. 32 Dowling and coworkers revealed that cho concentrations and NAA in tumor tissue were higher than normal values cancer. 33 In this study, our result reported that the cho/cr was independent relevant factors for death and progression (P = 0.006; P < 0.001). Whether the cho cr were not correlated with prognosis on NSCLC with BM.
Accumulating studies have substantiated that peripheral venous blood markers can re ect the condition of the host immune in ammation status. Counts of the peripheral immune in ammatory cells, such as platelet, lymphocytes, and neutrophils have been con rmed the reliable association link between in ammatory cells and prognosis in malignant tumors. [34][35][36][37] SII is an integrated parameter, including platelets, neutrophils and lymphocytes and has been proved to be an independent predictor of malignant tumors. 22,38−43 The value of SII in predicting clinical outcomes for cancer patients may be associated with the function of platelets, neutrophils, and lymphocytes. Platelets release growth factors and proangiogenic protein and protect tumor cells from immune response. 44 Neutrophils can take part in various stages of growth and metastasis of tumors and generate immunosuppressive effects by producing and secreting cytokines, chemokines, and proteases. 45 In contrast to neutrophils, lymphocytes exert important antitumor immune response and have been proved to be related to systematic immune surveillance. 46 In this study, the association between SII and clinical outcomes of patients in NSCLC with BM was evaluated. Our results indicated that SII was signi cantly associated with OS and PFS (P = 0.001; P = 0.002).
The clinician can evaluate clinical indicators such as tumor size, degree of tumor differentiation or tumor location, but these evaluation criteria are based on individual subjective evaluation and judgment. The heterogeneity of individual tumors is largely re ected in the biological characteristics of tumors and host immune in ammatory state. Consider a problem from multiple angles and you may nd new breakthroughs. Recently, many scholars have realized that combining two peripheral blood indexes can be considered useful independent prognostic markers in tumors. In the retrospective study initiated by Chen et al, their results revealed that the combination of circulating tumor cells with carcinoembryonic antigen has a better disease prediction than they were alone in NSCLC patients. 47  We established a C-SII score system by combining cho/cr and SII in this study, and preliminary results showed that it was an accurate and reliable system for evaluating prognosis in NSCLC patients with BM.
However, only 118 NSCLC with BM patients were conducted in this study because of the available limited number of enrolled cases. In addition, incomplete clinical data and loss to follow-up were inevitable because of the long duration of this retrospective study. There is selection bias when clinicians and radiologists use MRS to determine the ROI. These limitations require further evaluation and improvements in the future study.

Conclusions
High cho/cr and high SII for NSCLC patients were signi cantly to have poor outcomes in present study. C-SII score system may be used as a strong unfavorable survival index and assess risk strati cation for NSCLC patients with BM, which suggest clinicians to adjust the treatment strategy and generalize clinical application.  Figure 1 Patients screening process and results.    Correlations between Cho/Cr and SII.

Figure 6
Kaplan-Meier survival curves of Cho/Cr and SII in NSCLC patients with brain metastases. a overall survival curves of Cho/Cr. b progression-free survival curves of SII. c overall survival curves of Cho/Cr. d progression-free survival curves of SII Figure 7 Kaplan-Meier survival curves depicting outcomes of overall survival (a) and progression-free survival (b) according to the C-SII score.