Study Of Active Breathing Control In Intensity Modulated Radiotherapy For Primary Liver Cancer-Based On Liver Function Reservation Mode

Backgrounds and Objectives:The prognosis of patients with primary liver cancer is not only related to tumor burden,but also depends on the liver function.Gadoxetate disodium?Gd-EOB-DTPA?is a novel hepatocyte-specific MRI contrast agent that can be used to assess liver function in segment or sub-segment level.Active breathing control?ABC?can be used to reduce the external margins for radiotherapy of liver.Therefore,this study aims to compare the target volumes among 4DCT,free breathing 3DCT and ABC assisted 3DCT simulation for primary liver cancer.In addition,dosimetric differences between liver cancer function reservation intensity modulated radiotherapy?IMRT?and non-reservation IMRT planning were also compared.Toxicities and efficacy were also evaluated by CTCAE 4.0 and mRECIST 1.0,respectively.Methods:Patients with primary liver cancer received liver Gd-EOB-DTPA enhanced MRI within one week before radiotherapy.4DCT,the free-breathing 3DCT and ABC assisted3DCT scan were used for CT simulation.The simulation images were transferred to the TPS.The targets volume including GTVs,IGTVs,CTVs and PTVs were contoured by resident and approved by senior radiation oncologist.In ABC assisted 3DCT simulation,the liver function reservation volume was delineated for liver function reservation according to Gd-EOB-DTPA enhanced MRI hepatobiliary phase?20min?.The liver function reservation and non-reservation intensity modulated radiotherapy planning were made by senior physicists.The dosimetric differences between the two plans were compared.The acute adverse events and efficacy were evaluated by CTCAE 4.0 and mRECIST 1.0,respectively.Results:From January 2017 to December 2018,a total of 10 patients were enrolled.Eighty percent of the patients were males,the median age was 56 years?range 42⁷0 years?.Most of the tumors?72.7%?were located in the right lobe of the liver,and one patient have two lesions.Nine patients?90%?had a Child-Pugh A.The median volume of the whole liver was1378.85 cm³?range 1114.9²295.9 cm3?.There were no significant differences in GTVs,IGTVs,CTVs,and PTVs among 4DCT?20%?,free breathing and ABC-assisted 3DCT?P>0.05?.Compared with liver function non-reservation IMRT planning,the average dose of normal liver tissue,V5Gy-A,V10Gy-A,V15Gy-A,V20Gy-A,V25Gy-A,V30Gy-A,V35Gy-A,and V40Gy-A of reservation IMRT planning were significantly reduced?P<0.05?.No statistical differences in V₁₀₀,V₉₈,V₉₅,D_min,D_max,D_mean,right kidney V_20Gy-A,right kidney mean dose,left kidney mean dose,stomach V_40Gy-A,average dose of stomach,maximum dose of spinal cord,conformal index,and uniformity index between plans?P>0.05?.The V₂₀ of left kidney in both plans was 0.During or after the radiotherapy,one patient suffered from upper gastrointestinal bleeding and one occurred hepatitis B virus reactivation.The?/?grade toxicities including leukopenia?20%?,neutropenia?10%?,thrombocytopenia?20%?,fatigue?10%?.No obvious acute liver toxicity was observed.The objective response and response rate were 60%and 80%,respectively.Conclusions:Compared with 4DCT and free-breathing 3DCT scanning,ABC-assisted 3DCT scanning was larger in GTV and less in IGTV,CTV and PTV,but not significant differences.Using Gd-EOB-DTPA dynamic contrast enhancement MRI to reserve liver function,the intensity-modulated radiotherapy with ABC for the treatment of liver cancer can reduce the expose dose of normal liver and the volume to radiation without increasing the dose of organs at risk compared with conventional intensity-modulated radiotherapy.Liver function reservation with Gd-EOB-DTPA in the ABC assisted IMRT has potential to be a treatment option for patients with primary liver cancer.