Analysis Of The Effect Of Different Target Volume Delineations On The Prognosis And Recurrence Pattern Of Adult-type Diffuse Glioma

Purpose:This study aimed at patients with WHO grade 3 and 4 adult-type diffuse gliomas as the research subjects,aiming to investigate the effects of different target delineation patterns on the prognosis and recurrence patterns of patients after surgery and temozolomide（TMZ）based chemoradiotherapy treatment with Magnetic Resonance Imaging（MRI）.Furthermore,we studied the influencing factors of different recurrence patterns.Methods:A total of 118 patients with WHO grade 3 and 4 adult-type diffuse gliomas who underwent surgery,radiotherapy combined with TMZ chemotherapy at the Affiliated Hospital of Qingdao University from January 2017 to December 2020 and had complete follow-up data were included in the study.All patients’clinical data and molecular markers were collected,such as age,sex,surgical method,pathological classification of tumor occurrence site,O6-methylguanine-DNA-methyltransferase（MGMT）,Isocitrate Dehydrogenase（IDH）mutation,etc.Patients are divided into two groups based on their radiotherapy target delineation patterns,plan 1 and plan 2.The difference between the two schemes was whether the whole peritumoral edema（PTE）area was included in the irradiation range.The effects of different target volume delineation methods on the survival of patients were analyzed,as well as the effects of common clinical characteristics and molecular markers on the prognosis of patients were further analyzed.In addition,a total of 90 relapsed patients were confirmed by imaging or surgery.Images during postoperative follow-up were fused with the Computed Tomography（CT）images used for localization in the initial radiotherapy plan,and the recurrent tumor area(V_relapse)was delineated due to the V_relapseand 60Gy isodose curve（Isodose Line,IDL）on the basis of the original target.Tumor recurrence patterns were divided into central recurrence,in-field recurrence,marginal recurrence,and out-field recurrence.The presence of at least one strengthening foci discontinuous with other white matter on the ependymal surface of the ventricular system,the pia mater covering the surface of the cerebrospinal cord,or elsewhere in the subarachnoid space is defined as CSF dissemination,isolated from distant recurrence.To study the recurrence of adult-type diffuse glioma under different target profiling modes.According to the relationship between 20%V_relapseinvovled 60Gy equal dose curve,the recurrence pattern was divided into local recurrence group and non-local recurrence group,and whether different factors affected the tumor recurrence pattern was further investigated.Results:1.118 patients with WHO grade 3 and 4 adult-type diffuse gliomas were included in the study,with a median follow-up of 26.4 months（range,2.9–52.8 months）,divided into two groups,plan 1 and plan 2.The median progression-free survival（PFS）and overall survival（OS）of plan 1 were 9.5 and 26.4 months,respectively,and the median PFS and OS for plan 2 were 9.4 and 36.5 months,respectively.The difference between the two groups was not statistically significant（P=0.395;P=0.417）.2.According to the classification of pathological types,there were 32 cases of astrocytoma,10 cases of oligodendroglioma,and 66 cases of glioblastoma in 118 patients.There was no significant difference in prognosis between the two groups for different pathological types（P>0.05）.3.Survival analysis was performed on factors that may affect prognosis,such as age,sex,extent of resection,subventricular zone involvement,MGMT promoter,and Ki-67,and the results showed that age and surgical resection range affected PFS and OS,and MGMT promoter status only affected PFS（P<0.05）.4.Among the 118 patients,90 cases occurred recurrence,of which 58（64.4%）had central recurrence,10（11.1%）had in-feld recurrence,3（3.3%）had marginal recurrence,11（12.2%）had distant recurrence,and 8（8.9%）had cerebrospinal fluid dissemination,and there was no significant difference in recurrence patterns between plan 1 and plan 2（P=0.836）.5.The recurrence mode was re-divided into local recurrence group and non-local recurrence group,and there were no statistical differences in PFS and OS between the two groups（P=0.143;P=0.197）.6.Univariate analysis of factors influencing recurrence patterns showed that subventricular zone involvement and TERT promoter wild type were associated with non-local recurrence,and multivariate analysis showed that subventricular zone involvement was an independent risk factor for non-local recurrence.Conclusion:In our study,deliberately including or not the entire PTE had no impact on prognosis and recurrence.The pattern of relapse in patients is predominantly central recurrence.Patients with different recurrence patterns have different clinical and molecular features.