Distribution Of Metastatic Disease In The Brain In Relation To The Hippocampus:a Retrospective Single-center Analysis Of 565 Metastases In 116patients

Objective To observe the distribution of brain metastases(BM)with relation to the hippocampus,so as to explore the risk of metastasis in hippocampus,,then to provide scientific experimental evidence for the hippocampal avoidance(HA)of patients with BM during radiotherapy.Methods(1)Through the retrospective analysis of 116 certificated patients with malignancies that confirmed as BM between December 2014 to December 2016 in the First Affiliated Hospital of Bengbu Medical College,got the T1-weighted,postcontrast axial,sagittal,coronal MR images of patients,Get patients with supine position,use the head restraints and head thermoplastics to fix,with CT positioning scan ranging from the head to the mandible(layer thickness: 3mm.).CT and MRI images were fused on the philips pinnacle v9.8 treatment planning system;(2)Delineated every metastases of 565 metastases;(3)counted hippocampus,and hippocampus with 5mm expansion envelopes;(4)Using SPSS 16.0,analyzed the relation between the distribution and age,gender,Karnofsky(KPS),Primary site,Aggregate volume of intra-cranial metastases and the whole brain.Analyzed the data using a binary logistical regression analysis,with two-side P<0.05 for statistical significance.Results In this research,we got 116 patients with 565 metastases,Among them,1.7%(n=2)of patients have metastases in hippocampus,11.2%(n=13)of patients have metastases have metastases located within 5mm of hippocampus and more than half of them are patients of non small cell lung cancer(n=7).Using a binary logistical regression to analyze the relation of age(P=0.395),gender(P=0.139),KPS(P=0.724),primary site(P=0.894),aggregate volume of intra-cranial metastases(p=0.093)and the whole brain(p=0.998)to the metastases located within 5mm of hippocampus,which show no statistical difference between all of them(P>0.05).Conclusion This study showed a low risk for the perhippocampal metastases and no significant relation between PHM and age,gender,KPS,primary site,aggregate volume of intra-cranial metastases and the whole brain.As a result,it is acceptable to avoid the perhippocampal region during whole brain radiotherapy.