Clinical-pathologic Characteristics And Prognostic Factors For Malignant Peritoneal Mesothelioma In The Elderly

Objective: To investigate the clinicopathological features,prognosis and prognostic factors of elderly patients with malignant peritoneal mesothelioma(MPM).Methods: From the National Cancer Institute Surveillance Epidemiology End Results,1492 patients with malignant peritoneal mesothelioma from 1975 to 2016 were selected and divided into elderly group(≥ 65 years)and young and middle-aged group(< 65 years)according to age.The clinicopathological characteristics and treatment methods of elderly group(n = 665)and young and middle-aged group(n = 827)were compared,and the 1、3、5 year cancer-specific survival(CSS)were calculated.At the same time,univariate analysis was used to analyze the influence of gender,race,insurance status,marital status,tumor location,pathological type,degree of differentiation,stage,operation,radiotherapy and chemotherapy on the tumor specific survival rate of elderly patients with malignant peritoneal mesothelioma.Cox proportional hazard regression model was used to evaluate the independent risk factors of tumor specific survival.Results: Compared with the young and middle-aged group,the proportion of male in the elderly group was higher(58.80% > 52.60%),The proportion of white patients was higher(92.63% > 89.12%,P = 0.043),the proportion of insured patients was lower(35.94% <38.21%,P < 0.001),the proportion of married patients was lower(59.85% < 60.78%,P <0.001),and the proportion of peritoneal tumors was lower(94.74% < 97.58%,P = 0.006).The degree of differentiation was relatively poor compared with young and middle-aged patients.The rates of well differentiated patients(4.96% < 10.16%)and moderately differentiated patients(1.65% < 2.06%)were lower than young and middle-aged patients,and the rate of poorly differentiated patients was higher than young and middle-aged patients(7.22% > 5.68%).There was significant difference in the degree of differentiation between the two groups(P = 0.003).Among the elderly patients,the proportion of patients with tumor surgery was relatively low(33.38% < 47.88%,P < 0.001),and the proportion of patients with chemotherapy was relatively low(44.21% < 59.7%,P < 0.001).The survival time of the elderly group was generally shorter than that of the young group,with statistical difference.The median survival time of the elderly group was 6 months,and the1、3、5 year cancer specific survival rates were 36.19%、18.68%、12.53%,respectively.The median survival time of young and middle-aged patients was 19 months.The tumor specific survival rates of 1、 3、 5 year were 58.41%、36.96%、29.30%,respectively.Univariate analysis showed that gender,marriage,insurance,pathological type,degree of differentiation,stage,operation and chemotherapy were important prognostic factors of elderly patients with malignant peritoneal mesothelioma.Cox multivariate analysis showed that insurance,pathological type,differentiation degree,stage,operation and chemotherapy were independent risk factors for the prognosis of elderly patients with malignant peritoneal mesothelioma.Conclusion: Compared with young and middle-aged patients,elderly patients with malignant peritoneal mesothelioma have higher male ratio,poor differentiation and relatively conservative treatment.The tumor specific survival rate of elderly patients with malignant peritoneal mesothelioma was significantly lower than that of young and middleaged patients.Insurance,pathological type,degree of differentiation,stage,operation and chemotherapy are independent risk factors for the prognosis of elderly patients with malignant peritoneal mesothelioma.