Discussion On The Timing Of Local Stereotactic Radiotherapy For Stage IV NSCLC With Positive EGFR Mutation

ObjectiveIn this study,EGFR mutation-positive patients with stage IV non-small cell lung cancer were enrolled.Clinical data of patients with oral EGFR-TKI combined with stereotactic radiotherapy and combined stereotactic radiotherapy after local progression.The clinical data of the treated patients were compared.The timing of stereotactic radiotherapy for localized stage IV non-small cell lung cancer patients with positive EGFR mutations,and related prognostic factors were analyzed,to observe the survival benefit of early combined local stereotactic radiotherapy.MethodsWe collected 48 patients with newly diagnosed EGFR mutation-positive non-small cell lung cancer who were diagnosed and treated in our hospital from June 2013 to May 2017.The TNM stage was IV,and the patients were divided into therapeutic group and control group.The therapeutic group received oral EGFR-TKI combined with local lesions for stereotactic radiotherapy until the disease progressed;the control group received oral EGFR-TKI,evaluated the efficacy after 3 months,forpatients with local progression,local lesion combined with stereotactic radiotherapy.and then patients in both groups continued to take EGFR-TKI orally until the disease progressed further.Local lesion control was analyzed at 3 and 6 months.Results1、After 3 months,the objective response rate(ORR)was 53% and 54%,and the disease control rate(DCR)was 78% and 76%,respectively.After statistical analysis,there was no difference(P>0.05).After 6 months of evaluation,the objective response rate(ORR)of the two groups was 81% and 67%,respectively.The disease control rate(DCR)was 95% and 83%,respectively.After statistical analysis,the difference was statistically significant(P <0.05).2、Univariate survival analysis showed that the age,gender,KPS score,EGFR mutation status,oral EGFR-TKI drug type,and smoking history were not associated with progression-free survival(P>0.05).The diameter of tumor lesions,the status of lymph node metastasis and the timing of local stereotactic radiotherapy were associated with the prognosis of patients with newly diagnosed stage IV EGFR mutation-positive non-small cell lung cancer(P<0.05).3、The results of multivariate survival analysis indicated that the diameter of local tumor lesions,the status of lymph node metastasis and the timing of local stereotactic radiotherapy were independent prognostic factors for patients with EGFR mutation-positive non-small cell lung cancer at the initial stage IV.The median progression-free survival time of the tumor lesion < 5cm was longer than that of the lesion ≥ 5cm(P < 0.05).The median progression-free survival time was longer in patients with no lymph node metastasis than those with lymph node metastasis(P<0.05).Median progression-free survival prolonged in patients with early EGFR-TKI combined with local stereotactic radiotherapy(P<0.05).Conclusion1、In patients with stage IV non-small cell lung cancer with positive EGFR mutation,oral EGFR-TKI combined with local stereotactic therapy can benefitclinically,improve local tumor control rate,and prolong the median progression-free survival time.2、In patients with stage IV non-small cell lung cancer who were positive for EGFR mutation,oral EGFR-TKI combined with local stereotactic radiotherapy was feasible,and there was no significant increase in toxic side effects.3、Tumor lesion diameter,lymph node metastasis status and local stereotactic radiotherapy timing,are independent risk factors for patients with disease.The larger the tumor lesion diameter,with lymph node metastasis,the worse the patient’s prognosis.The median progression-free survival time is extended with concurrent local stereotactic radiotherapy.4、Local great segmentation stereotactic radiotherapy is considered to produce distant effect,which enables patients to generate an immune response and release immune factors,and combined with EGFR-TKI enhances the systemic anti-tumor effect.