Efficacy of gamma knife stereotactic radiotherapy and whole-brain radiotherapy in treatment of brain metastases

Objective To analyze the efficacy and prognosis of stereotactic radiotherapy (SRT) and whole-brain radiotherapy (WBRT) in treatment of brain metastases,and to observe the influence of temozolomide (TMZ) on survival rate during the period of radiotherapy.Methods A total of 52 patients with brain metastases were divided into two groups according to treatment methods,including 35 patients treated with WBRT plus SRT and 17 patients treated with SRT alone.WBRT dose was 1.8 - 3.0 Gy per fraction,one fraction a day,five fractions per week,with total dose of 30 - 40 Gy.After WBRT,gamma knife was performed with prescription isodose line of 45％ -70％ surrounding the planned target volume in WBRT + SRT group.The marginal dose was 12 - 15 Gy and the center dose was 20-30 Gy.In SRT group,the prescription isodosc line was 45％ - 70％ and the marginal dose was 36 - 40 Gy while the center up to 70 - 80 Gy.The follow up time was 1 - 2 years.Besides 20 patients in this study took temozolomide capsule during and after radiotherapy.The schedule of concomitant chemotherapy was temozolomide of 75 mg/m2 by oral administration every day until radiotherapy was over,and then temozolomide of 150 mg/m2 was taken for 3 -6 months after radiotherapy.Results The efficiency during 1 -3 months after treatment was 84.62％ in this study.In the WBRT + SRT group,the efficiency was 88.57％ and declined to 76.47％ in the SRT group.The six month-and one year-local control rate were 92.10％ and 85.20％,respectively.The average survival time of WBRT + SRT was 13.2 months and median survival time was 11 months.Six month-,one year-and eighteen months-survival rate were 71.40％,54.30％ and 14.30％,respectively.In the SRT group,the average survival time was 10.2 months and median survival time was 9 months.Six month-,one year- and eighteen month-survival rate were 41.20％,23.50％ and 5.88％,respectively,while those for RT + TMZ group were 80.00％,60.00％ and 10.00％.In comparison,those in RT group were 56.30％,37.50％ and 12.50％,respectively.Conclusions Effect of gamma knife stereotactic radiotherapy combined with WBRT is better than GK stereotactic radiotherapy alone in treatment of brain metastases.Compared with radiotherapy alone,concomitant temozolomide chemotherapy could improve the survival rate of the patients with brain metastases without increasirg adverse reactions significantly. Key words: Gamma knife;  Stereotactic radiotherapy;  Brain metastases;  Temozolomide