| Objective:By retrospectively analyzing the clinical efficacy and toxicity of fractional stereotactic radiotherapy for non-small cell lung cancer brain metastases,the effectiveness and safety of fractional stereotactic radiotherapy for non-small cell lung cancer brain metastases were evaluated.Methods:In this study,the clinical data of patients with brain metastases from non-small cell lung cancer treated by fractionated stereotactic radiotherapy in Jiangxi Cancer Hospital from January 2015 to June 2018 were collected,and the inclusion criteria and exclusion criteria were set.Stereotactic radiotherapy was performed with head,neck and shoulder plug-in S-shaped thermoplastic film fixed posture.Brain CT and MRI enhanced localization scans were performed to obtain localization images.Image fusion was performed on the radiotherapy planning system(TPS),and tumor targets and endangered organs such as eyeball,lens,optic nerve,optic chiasma and brainstem were delineated,and radiotherapy planning was designed and evaluated.The gross tumor volume(GTV)is defined as the contrast-enhanced tumor boundary,and the external 3mm to form the planned target volume(PTV),requires an isodose curve with a prescription dose of more than 95% to cover PTV.The methods of tumor dose segmentation included prescription dose 6Gy × 7 times,7Gy × 6 times,8Gy × 5 times,once every other day,3 times per week.Dose limitation of endangering organs: eyeball: Dmax < 20Gy;lens:Dmax ≤5Gy;brainstem: Dmax < 31Gy;optic nerve and optic chiasma Dmax < 25 Gy.6MV-X rays of electron linear accelerator were used in radiotherapy.All patients were reexamined with enhanced MRI,within 3 months after radiotherapy,and the short-term efficacy was compared with that of pre-treatment of craniocerebral MRI.Follow-up and observe the long-term effect.The objective remission rate,local control rate,survival rate and their influencing factors were analyzed.The short-term efficacy was evaluated by the 2009 RECIST1.1 version ofsolid tumor evaluation criteria.Central nervous system(CNS)radiation injury according to the American Association of Oncology radiotherapy(RTOG)acute radiation injury classification standard,the Kaplan-Meier method was used to calculate the median survival time and survival rate.SPSS22.0 software was used for statistical analysis,the local control of tumor after FSRT treatment was analyzed by*chi-square test,the measurement data were expressed by mean ±standard deviation by single factor analysis of variance,and the counting data were selected by chi-square test,when P < 0.05.The difference was statistically significant.Results:According to the inclusion criteria and exclusion criteria of this study,a total of72 patients were enrolled in the group.All the 72 patients had primary tumor pathological diagnosis,including 53 cases of adenocarcinoma and 19 cases of squamous cell carcinoma,aged from 36 to 77 years old,the median age was 63 years old,49 cases were male and 23 cases were female.the treatment of primary lung tumor includes operation,synchronous or sequential radiotherapy,systemic chemotherapy,targeted drug therapy and so on.Of the 72 patients,39 were complicated with extracranial metastasis.Brain metastases were found in 38 cases and more than 1 in 34 cases,the sum of the maximum diameters of each focus was less than 2cm in 22 cases and greater than 2cm in 50 cases,the sum of lesion volumes was less than 3cm3 in 29 cases and greater than 3cm3 in 43 cases;The prescription dose and biological effect dose were 6Gy × 7 times(BED67.2Gy)in 32 cases,7Gy ×6 times(BED71.4Gy)in 19 cases and 8Gy × 5 times(BED72.0Gy)in 21 cases.In the whole group,the short-term effect of brain metastasis reached CR in 11 cases(15.28%),PR in 51 cases(70.84%),SD in 5 cases(6.94%),PD in 5 cases(6.94%);the objective remission rate was 86.12%,and the local control rate was 93.06%.Among the 72 patients,8 patients had grade 1 and 2 CNS acute radiation damage,and no grade 3 or more CNS radiation damage.The median survival time of 72 patients was11 months,and the 6-month,1-year,2-year and 3-year survival rates were 66.7%,47.2%,22.1% and 11.2%,respectively.Univariate analysis of the local control rate of brain metastases showed that therewas no significant difference in the effect of various clinical factors such as dose segmentation mode on the control rate(P > 0.05),while the univariate analysis of survival showed that pathological type(P > 0.013),extracranial organ metastasis(P =0.000),targeted therapy(P = 0.000)and the number of brain metastasis(P = 0.025)were the influencing factors of survival.Multivariate analysis of survival showed that extracranial organ metastasis(Purge 0.014),targeted therapy(Purge 0.002)and number of brain metastasis(0.018)were the influencing factors of patients’ survival.Conclusion:1.Fractionated stereotactic radiotherapy for brain metastasis of non-small cell lung cancer is safe and effective.2.Stereotactic radiotherapy for brain metastasis of non-small cell lung cancer was performed with a prescription dose of 6Gy × 7 times,7Gy × 6 times and 8Gy × 5times,that is,the biological effect dose(BED)67.2Gy,71.4Gy and 72.0Gy all had similar tumor local control rates.3.The survival time of patients with brain metastasis of non-small cell lung cancer is related to the pathological type,the number of brain metastases,the presence of extracranial organ metastasis and the use of targeted therapy. |
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