Effects Of Prophylactic Cranial Irradiation And Its Different Optional Time On Prognosis Of Limited-stage Small Cell Lung Cancer

Objective:To observe the impact of the prophylactic cranial irradiation(PC I)and its different interventional time on the limited-stage s mall cell lung cancer(LD-SC LC)patients who had achieved complete response(CR)or partial remission(PR)with comprehensive therapy.Methods:The 184 LD-SC LC patients who received radiothera py and chemotherapy based comprehensive treatment were retrospectivel y anal yzed.There were 50 patients(27.2%)in the PC I group and 134 patients(72.8%)in the non PC I group according to whether receive PC I.The PC I group was enrolled into two groups accord ing to whether had complete d 4 cycles chemotherapy.The y were PC I1(n=20)who received chemotherapy less than 4 cycles and PC I2(n=30)who received chemotherapy geater than or equal to 4 cycles.The chemotherapy regimen s,irradiation method s and doses of the enrolled patients were the same.Results:The brain metastasis rate of PC I group and non PC I group were 14.0% and 30.6% respectivel y.There was a statisticall y significant difference in the incidence of brain metastases between the two groups(P<0.05).Incidence of cumulative brain metastasis at 6 months,12 months,and 24 months in patients with brain metastases in the PC I and non-PC I groups were 4.0%,6.0%,10.0% and 11.9%,17.9%,29.9%,significant differences in the incidence of brain metastases at 12 months and 24 months in the two groups(P<0.05).The median survival time of PC I group and non PC I group were 25 months(95%C I: 21.487-28.513),17 months(95%C I: 15.175-18.825)(P<0.05),and the 1,2 and 3-year survival rates of the two groups were 78%,40%,16% and 56%,21.6%,8.2%,there was a statisticall y significant difference between the median survival time and 1-year and 2-year survival rates in the two groups(P<0.05).Brain metastasis rate of PC I1 group and PC I2 group were 10.0%,16.7%,the difference was not statisticall y significant(P<0.05).The median survival time of the two subgroups had no significant difference.Conclusion:PC I can reduce the brain metastases incidence of SC LC,prolong the metastasis time and the overall survival time(OS),but it not significantl y increase the occurrence of adverse reactions in the central nervous s ystem.PC I with different intervention time did not show significant effect on the prognosis of LD-SC LC.