Reevaluation Of The Clinical Value Of Prophylactic Cranial Irradiation In Limited-stage Small Cell Lung Cancer In The Real World

Objective:The purpose of this study was to investigate the population characteristics of LS-SCLC patients who achieved CR or PR after initial treatment and were confirmed by CT/MRI to benefit from PCI without brain metastasis and the survival of patients with different PCI delivery methods,so as to provide reference for PCI treatment of LS-SCLC.Methods:A total of 498 patients with small cell lung cancer confirmed by pathology had been selected to retrospectively analyze in the fourth hospital of Hebei medical university from January 1st 2014 to December 31th2017.Among those,the median age was 59 years?22-79 years old?,317 cases were male and 181 cases were female.There were 50 cases in stage?,59cases in stage?,389 cases in stage?.There were 210 cases in PCI group?radiotherapy dose 25-40Gy?and 288 cases who had not received PCI.There were 116 cases who had received surgery and chemotherapy.There were 307cases received chemoradiotherapy,and 75 cases received chemotherapy alone.OS and BMFS were analyzed between PCI group and observation group,as well as the different PCI delivery methods on survival condition were explored.Results:1. Survival analysis1)The median OS of the whole group was 40.0 months?95%CI:33.44?46.56?,and 1-,3-and 5-year survival rates were 95.0%,53.4%and 37.3%,respectively.The median BMFS of the whole group were not reached,and 1-,3-and 5-years BMFS were 89.3%,71.4%and 70.2%,respectively.2)The survival rate of female was significantly better than male??2=4.160,P=0.041?.The survival rate of T_1-2 patients was significantly better patients was significantly better than that of N_2-3 patients??2=20.717,P=0.000?.The survival rate of stage I-II patients was significantly better than that of stage III patients??2=17.692,P=0.000?.The survival rate of patients in the surgery combined with chemotherapy group was significantly better than that of patients of chemoradiotherapy group and better than the patients with chemotherapy alone.in the chemotherapy alone group??2=27.854,P=0.000?.The survival rate of patients achieving CR after initial treatment was significantly better than that of those with PR??2=19.716,P=0.000?.3)The OS and BMFS of the PCI group were significantly better than those of the control group??2=10.987,P=0.001;?2=24.296,P=0.000?.2. Subgroup analysis1)In elderly patients?65 years old,there was no significant difference in OS and BMFS between the PCI group and the control group??2=2.002,P=0.157;?2=2.763,P=0.096?.However,in patients<65 years old,OS and BMFS were significantly better of the PCI group than those of the control group??2=7.979,P=0.005;?2=21.207,P=0.000?.2)In patients with stage of I-II,PCI marginally improved OS??2=3.572,P=0.059?,and the BMFS of the PCI group was superior to that of the control group??2=5.851,P=0.016?.In patients with stage of III,the OS and BMFS of the PCI group were significantly better than those of the control group??2=11.548,P=0.001;?2=21.647,P=0.000?.3)For those patients achieving PR,the OS and BMFS of the PCI group were significantly better than those of the control group??2=8.507,P=0.004;?2=10.149,P=0.001?.In patients achieving CR after initial treatment,there was no significant difference in OS between the PCI group and the control group??2=1.919,P=0.166?,but BMFS of the PCI group was significantly better than that of the control group??2=16.155,P=0.000?.3.Analysis of PCI delivery mode1)There was no significant difference in OS or BMFS between the early or late PCI group??2=0.049,P=0.825;?2=0.483,P=0.487?.2)There was no significant difference in OS or BMFS between the three different PCI doses groups??2=1.801,P=0.406;?2=0.330,P=0.848?.Conclusions:1.Patients of female,T_1-2,N_0-1,stage I-II,surgery combined with chemotherapy,CR and undergoing PCI have a better prognosis.2. In patients with LS-SCLC who achieve CR and PR after initial treatment and no brain metastasis confirmed by CT/MRI,PCI significantly improved overall survival,and reduced the risk of brain metastasis.3. Patients<65 years old can benefit from PCI,while elderly patients?65 years old with PCI have no obvious survival advantage,but the risk of brain metastasis may marginally reduce.4. In patients with stage of III can benefit from PCI,while PCI marginally improved OS in patients with stage of I-II,and reduced the risk of brain metastases.5. In patients whose tumor resonse after initial treatment showing PR can benefit from PCI,while CR patients undergoing PCI had lower risk of brain metastases although there is no survival advantage.6. No significant improvement in survival and brain metastasis was found with PCI intervention time.7. The high-dose PCI had no advantage over low-dose group.