Prognostic Value Of Imaging Features Combined With Molecular Pathology In Lower-grade Gliomas

BackgroundLower-grade gliomas(LGGs)include WHO grade II and III diffuse invasive gliomas,which arise most often in the cerebral hemispheres of adults and include astrocytomas,oligodendrogliomas,and oligoastrocytomas.Because of their invasive nature and characteristics of tissue infiltration,complete neurosurgical resection is impossible.After a period of time interval,some of the residual tumor tissues will relapse or progress to higher malignant tumor types,such as glioblastoma(WHO Ⅳ)with the highest degree of malignancy.However,some tumors have mild biological nature,and can remain stable for several years after surgery.Correspondingly,in terms of radiotherapy and chemotherapy,some of these LGGs are very sensitive to treatment,while the others are not sensitive to treatment.The treatment effect varies greatly,and the survival time ranged from 1 year to 15 years.Therefore,the accurate classification and prognosis prediction of LGGs still have great challenges.At present,the understanding of tumor has developed to the level of molecular gene.Many molecular markers have been found,such as isocitrate dehydrogenase(IDH)gene mutation,1p/19q codeletion,telomerase reverse transcriptase(TERT)promoter mutation and so on,which are closely related to the occurrence,development,classification and prognosis of glioma.Subsequently,according to the status of IDH mutation and 1p/19q codeletion,some studies divided lower-grade gliomas into three molecular subgroups with different prognosis.Moreover,in the 2016 World Health Organization(WHO)Classification of Central Nervous System(CNS)Tumors,the status of IDH mutation and 1p/19q codeletion were included in the characteristics of glioma classification,which guided the treatment and prognosis of LGGs,and established the important role of molecular pathology in the diagnosis and treatment of glioma.However,to obtain the information of molecular pathology,it generally needs invasive surgery or biopsy to get pathological tissue for gene detection,which has certain risks and accidents.Therefore,it is particularly important to evaluate the lesion status and predict the prognosis of patients through some safe and noninvasive examination methods.In recent years,radiomics has become the forefront and hot spot of research.Many studies have shown that imaging features are closely related to the grading of glioma,the prediction of molecular pathology and the prognosis of patients.It provides a new idea and method for us to predict the prognosis of LGG.In addition,based on the three molecular subtypes of LGGs,imaging features are added for further research,aiming to make new discoveries and breakthroughs in more accurate classification and prognosis prediction of LGG.ObjectivesTo investigate the prognostic value of MRI features in LGG and the classification of LGG combined with molecular pathology.MethodsThe clinical,pathological and imaging data of 252 patients with Grade II/III gliomas who accepted surgery in the First Affiliated Hospital of Zhengzhou University from January 2013 to January 2018 were retrospectively analyzed.According to VASARI imaging features,252 patients were analyzed.Kaplan-Meier method was used to calculate the overall survival(OS)and progression free survival(PFS).Log-rank test was used to compare the survival rates of various prognostic factors.Cox regression was used for multivariate analysis.ResultsUnivariate and multivariate analysis showed that enhancement quality,proportion enhancing and satellites around the tumor were independent risk factors for the prognosis of patients with lower-grade gliomas.The 5-year OS of patients with no enhancement,mild enhancement and marked enhancement were 87.9%,81.0%and 29.8%,respectively(P<0.001).The 5-year OS was 87.9%and 88.2%in patients with no enhancement and less than 5%enhancement,which was higher than that in other patients(P<0.001).The 5-year OS was 67.6%in patients with no satellite tumor and 7.7%in patients with satellite tumor(P<0.001).The 5-year PFS was 85.2%,59.4%and 22.5%in patients with no enhancement,mild enhancement and marked enhancement,respectively(P<0.001).The 5-year PFS was 85.2%in patients with no enhancement,which was higher than that in other patients,and the overall difference was statistically significant(P<0.001).The 5-year PFS was 60.3%in patients with no satellite tumor and 7.7%in patients with satellite tumor(P<0.001).Based on the important role of molecular pathology in LGGs and the impact of imaging features on the prognosis,LGGs were further divided into six different subgroups(P<0.001),namely IDH mutant and 1 p/19q codeletion-no marked enhancement group(subgroup 1),IDH mutant and 1p/19q codeletion-marked enhancement group(subgroup 2),IDH mutant but no lp/19q codeletion-no marked enhancement group(subgroup 3),IDH mutant but no 1p/19q codeletion-marked enhancement group(subgroup 4),IDH wild type-no marked enhancement group(subgroup 5),IDH wild type-marked enhancement group(subgroup 6).In addition,according to the number of cases in each subgroup and their differences,the six subgroups were divided into four independent prognostic risk groups(P<0.001).ConclusionsEnhancement quality,proportion enhancing and satellites around the tumor were independent risk factors for the prognosis of patients with lower-grade gliomas.Tumors with marked enhancement or satellites were associated with worse OS and PFS,but the proportion enhancing could not distinguish OS and PFS.In addition,according to the status of IDH mutation and 1p/19q codeletion,which are two important molecular pathological features,combined with the imaging features of tumor enhancement,the lower-grade gliomas were divided into six different subgroups,and further divided into four different prognostic risk groups.Moreover,the difference of OS between the four prognostic risk groups is obvious,which can well distinguish the prognosis of patients with lower-grade gliomas.Therefore,we get that MRI feature is an important indicator to predict the prognosis of patients with lower-grade gliomas.Combined with the current classification of lower-grade gliomas by molecular pathology,we can more finely guide the classification and prognosis prediction of LGGs,so as to achieve the purpose of precision medicine and individualized medicine.