The Prognostic Of CT-Based Skeletal Muscle Parameters In Patients With Advanced Non-Small Cell Lung Cancer

Objective: This study investigated the effect of CT-based skeletal muscle parameters on the prognosis of patients with advanced non-small cell lung cancer who received first-line chemotherapy,and provided new ideas for improving the prognosis of patients.Methods: The clinical,imaging,and pathological data related to advanced non-small cell lung cancer patients who attended our hospital between June2017 and December 2019 were collected,and regular follow-up was performed to obtain information on patient survival data.Computed tomography(CT)images were obtained before the start of treatment.skeletal muscle parameters,including skeletal muscle index(SMI)and skeletal muscle density(SMD),were assessed by semi-automatically outlining the horizontal cross-sectional total muscle area of the third lumbar vertebra(L3)with a post-processing system(GE-AW4.7).Based on the best cut-off values for diagnosing sarcopenia(low SMI)and muscle fat infiltration(low SMD)internationally,patients were divided into sarcopenia group and non-sarcopenia group,muscle fat infiltration group and non-muscle fat infiltration group.Then,the differences in general clinical information and clinicopathologically relevant characteristics were compared between the two groups,respectively.The correlation between SMI,SMD and BMI and the relationship between baseline SMI and SMD levels and chemotherapy efficacy were analyzed.The Kaplan-Meier method was used to draw the survival curve and analyze the overall survival rate of the patients.Cox regression analysis was used to conduct univariate and multivariate survival analysis,so as to explore the effect of CT-based skeletal muscle parameters SMI and SMD on the prognosis of patients with advanced non-small cell lung cancer.Results:1.Basic information: A total of 112 patients with advanced non-small cell lung cancer were included in this study.Males were more common than females,of which 83(74.1%)were male and 29(25.9%)were female;the average age was 59.41±9.25 years old;tumor size Patients with ≤5cm were more common(61/54.5%);the pathological type was squamous cell carcinoma(58/51.8%);The number of metastatic organs(1-2)patients was 91(81.3%),which was much more than the number of metastatic organs(>2)patients.There were 43(38.4%)cases of smoking patients;peripheral lung cancer was more common in imaging classification(58/51.8%);pemetrexed(PEM)was the most common first-line chemotherapy regimen(61/54.5%).2.Comparison of clinicopathological features of sarcopenia group(low SMI)and non-sarcopenic group(high SMI): A total of 63 cases were diagnosed with sarcopenia,the incidence rate was 56.3%,and the incidence rate in males was 71.1%(59/83),the incidence of females was 13.8%(4/29);There was a statistical difference between the two groups in the proportion of gender distribution,pathological subtypes and the number of metastatic organs(P <0.05).The median age and tumor size were higher in the sarcopenia group compared to the non-sarcopenia group(P < 0.05).The sarcopenia group had lower skeletal muscle index SMI,body mass index BMI,and skeletal muscle density SMD(P < 0.05).There were no statistical differences between groups in other clinicopathological characteristics(P > 0.05).3.Comparison of clinicopathological characteristics of muscle fat infiltration group(low SMD)and non-muscle fat infiltration group(high SMD):A total of 46 cases were diagnosed with muscle fat infiltration,the incidence rate was 41.1%,including 32.5%(27/83)in men and 65.5%(19/29)in women.The two groups were statistically different in terms of gender ratio,average age value,age distribution,BMI,SMD and SMI(P <0.05).There was no statistical difference between groups in other clinicopathological features(P >0.05).4.Correlation analysis between baseline SMI,SMD and BMI: there was a moderate correlation between baseline SMI and SMD,and a linear positive correlation(P <0.01);the correlation between baseline BMI and SMD and baseline BMI and SMI were very weak.5.Relationship between baseline SMI and SMD levels and chemotherapy efficacy: objective remission(CR/PR)was not related to baseline SMI and SMD levels(P > 0.05).Disease control(CR/PR/PD)was also not related to baseline SMI and SMD levels(P > 0.05).6.Survival outcome analysis: the overall patients’ cumulative survival rates at 1,2,and 3 years were 82.0%,37.8%,and 14.6%.the mean survival time was23.38 ± 1.46 months,and the median survival months was 19 months.The mean survival time was lower for patients in the sarcopenia group compared with the sarcopenia group(19.59 ± 1.48 months and 26.87 ± 2.46 months).The mean survival time of the muscle fat infiltration group was lower than that of the non-muscle fat infiltration group(19.19±1.67 months and 25.73±1.91 months).Univariate survival analysis showed that sarcopenia,muscle fat infiltration,gender,number of metastatic organs,and body mass index were prognostic factors in patients with advanced non-small cell lung cancer(P <0.05).Multivariate survival analysis showed that sarcopenia,muscle fat infiltration,gender,and body mass index were independent prognostic factors affecting the overall survival(OS)of patients with advanced non-small cell lung cancer in this study(P <0.05).Conclusions: CT-based sarcopenia(low SMI)and muscle fat infiltration(low SMD)were independent risk factors for poor prognosis in patients with advanced non-small cell lung cancer.Skeletal muscle parameters(SMI,SMD)have good prognostic value for the prognosis of patients with advanced non-small cell lung cancer.