| Objective: To observe the local control rate, survival rate and side effectsof the patients with one to three brain metastases by whole brain radiotherapy(WBRT) with local simultaneous integrated boost conformal radiotherapy(SIB-CR), to explore the feasibility of the technology and to evaluate thesurvival prognostic factors in patients with brain metastases.Methods: Twenty-one patients with one to three brain metastasesconfirmed by enhanced MRI/CT were prospectively collected and treated bywhole brain radiotherapy with local SIB-CR from August11,2011to October12,2012. All patients were immobilized by head thermoplast and scanned onthe CT simulator. Then the CT images were transmitted to the ADAC pinnacle8.0treatment planning system. The target volume and organs at risk (OARs)were outlined based on enhanced MRI/CT images. GTV was metastaticlesions in the brain and PTV was defined as the GTV plus a5mm. PTV1wasthe whole brain. Simultaneous integrated boost conformal radiotherapy(SIB-CR) was used in all patients. The prescribed dose of PTV1was39.6Gy/22fractions and PTV was given to55Gy/22fractions simultaneously.The total treatment time was about4.5weeks (1time a day,5days a week).The acute radiation toxicities such as radiation cerebral edema, epilepsy anddigestive sympotoms were observed from the start of treatment to four weeksafter the end of treatment and graded according to the CTC-AE3.0toxicitygrading criteria. The late toxicities mainly included the patients’ quality of life,cognitive function and central nervous system damage. The tumor responsewas evaluated at4weeks after the end of radiotherapy. The overall survivaland intracranial progression-free survival time were calculated from the day oftreatment until death, intracranial progression or the last follow-up date. Survival was analyzed by the Kaplan-Meier method, and the COX regressionanalysis was used for analyzing prognostic factors. The difference between thevarious subgroups compared using the Log-rank test. The impact on survivalby different RPA classifications, KPS scores, number of metastases and so onwas compared. Statistical analysis was performed by SPSS13.0software.Results:(1) There were11male and10female patients in the wholegroup. The median age was52years (range:39-72).(2) Fourteen patientsreceived radiotherapy alone while seven cases received radiotherapycombined with chemotherapy.(3) Tumor response: The complete response(CR) was2patients (9.5%), the partial response (PR)16patients (76.2%) andthe stable disease (SD)3patients (14.3%). The overall tumor response(CR+PR) rate was85.7%(18/21).The clinical benefit rate (CR+PR+SD)was100%.(4) The median follow-up time was7months (range:1-12.5) with100%of follow-up rate; Until the follow-up cut-off time, there were five casesdead, including3cases died of intracranial lesions, and the cause of death ofthe other two cases was unknown; Three cases had recurrence, two of whichoccurred in the original tumor bed area and the one occurred intracranialmetastasis far from the original tumor. The rate of overall brain control (BC)was85.7%(18/21), the local control rate (LC)90.5%(19/21), the distantcontrol rate (DC)95.2%(20/21).(5) The overall median survival time was7months. The6-month OS and intracranial PFS rates were76.6%,61.3%respectively. The1-year OS and intracranial PFS rates were61.3%,65.6%respectively. The1-year survival rate of patients treated with radiotherapyalone was69.3%, while the patients treated with radiotherapy withchemotherapy was85.7%, the difference was not statistically significant(P=0.25).(6) In the univariate analysis, tumor response, KPS score beforeradiotherapy and RPA classification were found correlated with survival.Multivariate analysis showed that the RPA classification was correlated withsurvival. Survival rates among the patients with different grading of the RPAshowed that the median survival period of RPA1,2and3level were9,8and5months respectively (χ~2=7.73, P=0.02).(7) All patients were well tolerated during treatment. The symptoms of the nervous system improved significantlyafter treatment and KPS score were increased. The amounts of dehydrationdrugs were significantly decreased.Conclusion: Whole brain irradiation with SIB-CR technique is effectivein patients with one to three brain metastases with a higher tumor response andshorter the total radiotherapy duration and can be well tolerated. The patientswith KPS≥70, oligometastatic brain metastases and effective controlledprimary tumors can benefit from the local boost after WBRT. SIB-CRtechnology can provide a new option for these patients. The long-term survivaland late toxicities need to be further observed. |
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