Clinical Study Of Three-dimensional Conformal Radiotherapy Of Primary Liver Cancer And In Rat Liver After Exposure Of Liver Regeneration In Experimental Research

Part 1:CT and MRI image fusion in delineation of gross tumor volume for 3-D conformal and intensity modulated radiation therapy for hepatocellular carcinomaObjective:To investigate the accuracy of image registration with computed tomography(CT) and magnetic resonance imaging(MRI) and how to determine GTV for HCC.Material and Methods:Thirteen patients were enrolled in this study.The CT image was taken at inhalation phase,and MRIT2,at the time of peak exhalation. Additional image was taken by fast scanning of MRIT2(MRIT2F) at peak inhalation in six patients.After mutual information method to CT/MRI image registration, manual adjustment was made to optimize the accuracy of image fusion.The GTV and liver in each patient were independently contoured by two observers on CT,MRIT2 and MRIT2F images.The accuracy of image fusion was assessed by the distance between bone markers(D_CT-MRIT2,D_CT-MRIT2F) of CT and MRI on the fused image,and the ratio of liver overlap(P-LIVER_CT-MRIT2,P-LIVER_CT-MRIT2F).The measured were volumes of GTV contoured on CT(V-GTV_CT),or on MRIT2(V-GTV_MRIT2),or on MRIT2F(V-GTV_MRIT2F),their overlap(V-GTV_CT-MRIT2,V-GTV_CT-MRIT2F) and their composite volume(V-GTV_CT+MRIT2,V-GTV_CT+MRIT2F).The percentage of V-GTV_CT and V-GTV_MRIT2 on V-GTV_CT+MRIT2,V-GTV_CT and V-GTV_MRIT2F on V-GTV_CT+MRIT2F, V-GTV_CT-MRIT2 and V-GTV_CT-MRIT2F on V-GTV_CT was also calculated,respectively.Results:Accuracy of image fusion was the mean D_CT-MRIT2 of 2.7 mm±0.8mm and D_CT-MRIT2F of 2.1mm±0.9mm.The mean P-LIVER_CT-MRIT2 and P-LIVER_CT-MRIT2F were 85.9%±4.1%and 92.7%±1.5%.Interobserver difference was small for GTV defined by MRIT2,but there was significant difference for GTV defined by CT between two observers.V-GTV_CT,V-GTV_MRIT2 and V-GTV_MRIT2F were 387cm³Â±396cm³,488cm³Â±461cm³ and 597cm³Â±541cm³,respectively.The percentage of V-GTV_CT and V-GTV_MRIT2 on V-GTV_CT+MRIT2 was 66.2%±13.5%and 88.7%±10.2%,V-GTV_CT and V-GTV_MRIT2F on V-GTV_CT+MRIT2F was 71.3%±12.7% and 93.5%±4.8%,respectively.Conclusions:The fusion image of CT and MRI should be obtained at the same respiratory phase,in the same treatment position and with the same slice thickness and separation.Automatic registration was carried out by mutual information method using automatic registration software.When contouring GTV of HCC,CT and MRI image should be integrated.GTV used to be planned should be the sum of CT-defined GTV and MRI-defined GTV. Part 2:Phaseâ… trial of radiation dose escalation in patients with locally advanced hepatocellular carcinomaPurpose:To determine the maximum tolerated dose(MTD) of 3-dimensional conformal radiation therapy(3DCRT)/intensity modulated radiation therapy(IMRT) for locally advanced hepatocellular carcinoma(HCC).Materials and Methods:Inclusion criteria were as follows:pathologically confirmed or clinically diagnosed HCC,surgically unsectable or medically inoperable diseases,solitary intrahepatic lesion with diameter bigger than 5 cm,without extrahepatic and/or distant metastases,associated with cirrhosis of Child-Pugh A.The patients were divided into 2 subgroups:tumor diameter more than 5cm and less than 10cm(Groupâ… ) and larger than 10cm(Groupâ…¡).The starting radiation doses were 46Gy and 40Gy in 2Gy per fraction for Groupâ… and Groupâ…¡,and up to a chosen maximum of 62 Gy and 52 Gy with 4.0 Gy increments of each cohort.Dose-limiting toxicity(DLT) was defined as acute≥Grade 3 liver,gastrointestinal toxicity,or any grade 5 treatment-related adverse event,or late complication of radiation-induced liver disease(RILD).Results:From April 2005 to May 2008,a total of 40 HCC patients were enrolled in this study(20 in Groupâ… and 20 in Groupâ…¡).According to AJCC staging(2006), there were 20 cases of T2(â…¡stage),17 cases of T3(â…¢A stage)and 3 cases of T4(â…¢B stage),respectively.The last follow-up was performed in January 2009 with the median follow-up time of 17.5months for Groupâ… and 9 months for Groupâ…¡.The total median follow-up time was 13 months for all patients.Total 11(55.5%) patients (9 Grade 1 and 2 Grade 2) occurred acute treatment-related toxicities in Groupâ… and 10(50%) patients(8 Grade 1 and 2 Grade 2) in Groupâ…¡.For all patients,only one nonclassic RILD was observed in 52Gy dose level of Groupâ…¡,which occurred two months after completion of radiation treatment.After two weeks of symptomatic treatments,the patients died of hepatic failure eventually.4 patients developed in-field recurrence;21 patients had intrahepatic spreading;5 patients had extrahepatic metastases.The 2-year local control rate for all the patient was 90%.The 1,2 year overall survival rates was 72%and 62%for all the patients.Conclusions:The radiation dose was safely escalated in locally advanced HCC patients by using 3D-CRT/IMRT and ABC to 62Gy for patients with tumor diameter less than 10cm and 52Gy for tumor diameter equal or more than 10 cm under strict normal liver DVH constraints.The local control is satisfied with acceptable toxicities. Part 3:An experimental study of liver regeneration after liver irradiation on rats.Objective:To examine whether irradiated liver has the ability to regenerate after liver irradiation,and to investigate the timing of liver regeneration and the roles of participated cytokines on irradiated liver of rats.Material and Methods:Two parts were included in this study(Partâ… and Partâ…¡).In Partâ… ,rats were randomly divided into 0-day-post radiation(sham-radiation), 30-day-post-radiation,60-day-post-radiation,90-day-post radiation and 120-day-post-radiation group according to time of sacrifice on rats,and each group had six rats.The right half liver was irradiated with a single fraction dose of 25Gy and left half with 5Gy using 6MV-X ray.In Partâ…¡,all rats were sacrificed at the time of 60 days post irradiation and randomly divided into 5 groups.Sham-radiation group(0Gy) was also included.Other rats irradiated to right half liver with dose of 25Gy were randomly divided into 2.SGy,5Gy,7.5Gy,10Gy group according to the dose irradiated to left half liver,and each group also had six rats.All the rats were sacrificed at the scheduled time in each group of the two parts.Blood serum,right and left half liver tissue were collected.Hepatocyte growth factor(HGF),Alanine aminotranferease(ALT),aspartate aminotransferase(AST) and Prealbumin(PA) in blood serum were measured in each group.Mitotic index in liver tissue was assessed by H.E.staining.The expression of proliferation cell nuclear antigen(PCNA) and transforming growth factor-β1(TGF-β1) were confirmed by immunohistochemical staining.HGFmRNA,PCNAmRNA and TGF-β1mRNA were analysed quantificationally by real-time PCR.Proliferation index was determined by flow cytometry(FCM).Results:ALT and AST in blood serum of rats irradiated 25Gy to right half liver and 5Gy to the left escalated to their peak values at the time of 60 days after irradiation,and were 3.2 and 2.6 folds of normal level,respectively.PA in blood serum dropped to its peak value at the time of 60 days after irradiation,and was 0.4 folds of normal level.HGF in blood serum reached its peak at the time of 30 days after irradiation.Comparing to sham-radiation(0 day),60-day-post radiation, 90-day-post radiation and 120-day-post-radiation group,the differences were all significant(P＜0.05).In the liver tissue irradiated 5Gy,HGFmRNA and TGF-β1mRNA increased to their peak values at the time of 30 days after irradiation, PCNAmRNA and Proliferation index at the time of 60 days after irradiation and mitotic index at the time of 90 days after irradiation.In the liver tissue irradiated 25Gy,HGFmRNA and TGF-β1mRNA augmented to their peak values at the time of 30 days after irradiation and PCNAmRNA at the time of 90 days after irradiation. Four rats in the group of right half liver irradiated 25Gy and left half 10Gy died between the first and the second week.In groups irradiating left half liver form 2.5Gy to 7.5Gy,the expression of AST,ALT,PCNAmRNA and TGF-β1mRNA increased significantly with the dose escalation(P＜0.05).But there were no significant difference of PA and Mitotic index between groups mentioned above.Proliferation index in groups irradiating left half liver 5Gy and 7.5Gy showed no significant difference(P＞0.05),but both were higher than that in group irradiating 2.5Gy (P＜0.05).Conclusions:The liver tissue irradiated 25Gy still has regenerative potential; Irradiation can block the cell cycle of regenerative liver tissue and delay the course of liver regeneration;Rats can not tolerate the dose of 25Gy irradiated to right half liver and 10Gy to left half liver,and liver regeneration can not compensate for the acute injury of liver function in time.