Comparison Of Efficacy Between Two Dose Fractionation And Prognostic Analysis Of Different Treatment Strategies In Patients With Limitedstage Small Cell Lung Cancer

Objective:To compare the efficacy and safety of hypofractionated thoracic radiotherapy and conventionally fractionated radiotherapy,and to analyze the prognosis of different treatment strategies in patients with limited-stage small cell lung cancer.Methods:The data of 63 patients with limited-stage small cell lung cancer admitted to our hospital from January 1,2010 to February 28,2016 were analyzed.The conditions were confirmed by pathological or cytological diagnosis,limited stage and received radical chemoradiotherapy.The patients were divided into hypofractionated thoracic radiotherapy group(55 Gy/22 F/2.5 Gy)and conventionally fractionated radiotherapy group(60-70 Gy/30-35 F/2.0 Gy).The local control rate,progression-free survival time,median survival time and toxicity were statistically compared.COX regression analysis the influence of different chemotherapy regimens,the number of chemotherapy cycles before radiotherapy,the combination of radiotherapy and chemotherapy,and Prophylactic Cranial Irradiation on prognosis.Result:(1)The follow-up rate was 91.3%until March 1,2018.The one year local control rates of the hypofractionated thoracic radiotherapy group and the convention-ally fractionated radiotherapy group were 86.9%and 80%respectively(Χ~2=0.490,P=0.484);two year local control rates were 60.9%and 52.5%respectively(Χ~2=0.414,P=0.52).The median progression-free survival time was 14.8 and 12.0 months respectively(Χ~2=0.69,P=0.406);The one year progression-free survival rate was52.2%and 46.9%,respectively;the two year progression-free survival rate was 19.3%and 13.8%,no significant difference.The median survival time was 24.8and 19.2months,respectively(Χ~2=0.689,P=0.407);the 1-year survival rate was 82.6%and80.0%,respectively;the 2-year survival rate was 52.5%and 41.1%,respectively,the difference was not statistically significant.The incidence of radiation esophagitis above grade 3 was 8.7%and 12.5%,respectively(P=0.644);the incidence of radiation pneumonia above grade 3 was 4.3%and 5%,respectively(P=0.907),one of the patients in the conventionally fractionated radiotherapy group died of radiation pneumonia,there was no significant difference between the two groups.(2)Multivariate analysis showed that Prophylactic Cranial Irradiation(HR=0.432,95%CI:0.243~0.767,P=0.004),combination of radiotherapy and chemothe-rapy(HR=0.538,95%CI:0.298~0.970,P=0.039),and the number of chemotherapy cycles before radiotherapy(HR=0.451,95%CI:0.254~0.801,P=0.007)were independent prognostic factors affecting survival.Conclusion:For limited stage small cell lung cancer,hypofractionated thoracic radiotherapy and conventionally fractionated radiotherapy have similar efficacy and safety.hypofractionated thoracic radiotherapy may also be considered as a therapeutic option.Prophylactic Cranial Irradiation,combination of radiotherapy and chemoth-erapy,and the number of chemotherapy cycles before radiotherapy were independent prognostic factors affecting survival.