Clinical Study Of Helical Tomotherapy Radiotherapy Combined With Ct-based Intracavitry Radiotherapy In Treatment Of Locally Advanced Cervical Cancer

[Background]Cervical cancer is one of the most common malignancies in gynecology,and is the second leading female malignancy after breast cancer.At present,China has about 10 million new cases of cervical cancer every year,and the trend of young age.National Comprehensive Cancer Network(NCCN)guidelines recommend concurrent chemoradiotherapy as the standard treatment for locally advanced cervical cancer.The radiation therapy consists of external beam irradiation and intracavitary brachytherapy.Severe toxicity is reported in approximately 35-40%of patients with conventional radiotherapy.With the progress of imaging and computer technology,new radiation modalities like three dimensional-conformal radiation therapy(3D-CRT)and intensity-modulated radiation therapy(IMRT)have been applied to cervical cancer.IMRT provides excellent coverage of PTV whereas significantly reducing doses to the organs at risk(OAR)like small bowel,rectum,and bladder.As a novel method of IMRT,helical tomotherapy(HT),which combines helical computed tomography(CT)with megavoltage linear accelerator,delivers dose distributions in a helical pattern,and the megavoltage CT allows for setup verification.HT attains more conformal PTV coverage than IMRT,and reduces the dose of OAR.Intracavitary brachytherapy is an indispensable treatment for cervical cancer.Conventional brachytherapy is two-dimensional radiography.The limitations of two dimensional intracavitary brachytherapy includes:unable to adjust plan with the changing size or shape of tumor,unable to accurately assess the dose of the bladder and rectum,which leads to inadequate target coverage and insuffcient dose delivery.CT or MRI based three dimensional intracavitary brachytherapy has been used in the treatment of cervical cancer since 2000.CT-ICBT and HT have been used in the treatment of cervical cancer in our hospital since 2012 and 2014 respectively.The purpose of this study was to evaluate the toxicity and clinical outcome in patients with locally advanced cervical cancer treated with HT+CT-ICBT by analyzing dosimetry and clinical data retrospectively.Part I Dosimetry study of PTV and OAR between HT and IMRT[ABSTRACT][Objective]To investigate the difference of PTV and OAR between HT and IMRT.[Method]47 patients with FIGO?B-?B cervical cancer between January and December 2014 received concurrent chemoradiotherapy,dosimetry and clinical data were analyzed retrospectively.All patients received paclitaxel+cisplatin three weekly as the chemotherapy.22 patients were treated with HT+CT-ICBT,25 patients were treated with IMRT+ICBT.All patients underwent reduced field external beam radiation as follows:2880cGy delivered to the whole pelvic in 16 fractions,then the irradiated volume was reduced to lymphatic drainage region and parametrium for an additional 2160cGy boost in 12 fractions.Target volumes and OAR were delineated according to the recommendations of RTOG(Int.J.Radiation Oncology Biol.Phys.2010).Both the PTV and the OAR were analysed by DVH and isodose curves.To compare the dosimetric parameters of PTV and OAR for whole pelvis radiotherapy between HT and IMRT(2880cGy).To compare the dosimetric parameters of PTV and OAR for reduced field pelvis radiotherapy between HT and IMRT(2160cGy).To compare the dosimetric parameters of OAR for fusing whole pelvis radiotherapy plan and reduced field pelvis radiotherapy plan between HT and IMRT.[Results]1.Whole pelvis radiotherapy(2880cGy)?Isodose curves between HT and IMRT:The mean dose of PTV(Dmean)(Gy)of HT was 29.72±4.02,which was similar with IMRT(30.31±3.63.P=0.599).The volume of PTV receiving 105%of the prescription dose for HT was 9.80±2.26,which was similar with IMRT(10.31±2.06,P=0.422).PTV110%was zero both for HT and IMRT.The dose conformity(CI)was obviously improved with HT over IMRT(0.787±0.216 vs 0.656±0.221,P=0.046).The dose homogeneity(HI)for HT was 1.069±0.198,which was similar with IMRT(1.085±0.176;P=0.770).?Dosimetric parameters of OAR:The V40(%)of rectom,bladder,and bowel were obviously improved with HT over IMRT respectively(42.33±7.20 vs 49.68 ±7.94,P=0.001;33.91±6.82 vs 39.23±8.01,P=0.001;6.05±1.56 vs 7.19±2.02,P=0.037).But there were no significant difference in R-Femoral head and L-Femoral head between HT and IMRT(2.56±0.56 vs 2.93±0.52,P=0.721;3.01±0.68 vs 3.31±0.59,P=0.112).The mean dose of(Dmean)rectom,bladder,and bowel were obviously improved with HT over IMRT respectively(20.29±3.40 vs 23.07±4.85,P=0.029;17.95±5.34 vs 20.99±4.92,P=0.048;13.74±3.02 vs 15.55±2.91,P=0.042).No significant difference were found in R-Femoral head and L-Femoral head between HT and IMRT(12.27±3.06 vs 12.84±3.85,P=0.580;11.89±3.21 vs 12.92±1.45,P=0.154).2.Reduced field pelvis radiotherapy(2160cGy)?Isodose curves between RF-HT and RF-IMRT:The mean dose of PTV(Dmean)(Gy)of RF-HT was 22.25±5.12,which was similar with RF-IMRT(22.73±3.41.P=0.703).Both PTV105%and PTV110%was zero both for RF-HT and RF-IMRT.The dose conformity(CI)was obviously improved with RF-HT over RF-IMRT(0.800±0.202 vs 0.660±0.254,P=0.044).The dose homogeneity(HI)for RF-HT was 1.049±10.230,which was similar with RF-IMRT(1.051±0.147;P=0.972).?Dosimetric parameters of OAR:The V40(%)of rectom and bladder were obviously improved with RF-HT over RF-IMRT respectively(5.68 ± 0.48 vs 9.600±1.53,P=0.000;20.54±4.92 vs 26.68±3.46,P=0.000).But there were no significant difference in bowel,R-Femoral head and L-Femoral head between RF-HT and RF-IMRT(;5.97±0.44 vs 6.17±1.17,P=0.454;3.03±0.36vs 2.92±0.18,P=0.184;3.18±0.30vs 2.84±0.56,P=0.062).The mean dose of(Dmean)rectom and bladder were obviously improved with RF-HT over RF-IMRT respectively(11.57±2.22 vs 13.09±1.98,P=0.016;12.87±2.58 vs 14.66±3.02,P=0.035).No significant difference were found in bowel,R-Femoral head and L-Femoral head between RF-HT and RF-IMRT(10.48±1.53 vs 10.91±2.66,P=0.508;8.40±1.76 vs 8.10±2.26,P=0.0.617;8.49±1.02 vs 7.91±1.20,P=0.083).3.The Dmean(Gy)of OAR for fusing whole pelvis radiotherapy plan(2880cGy)and reduced field pelvis radiotherapy plan(2160cGy)between HT and IMRT.The mean dose of(Dmean)rectom,bladder,and bowel after PTV fusion were obviously improved with HT over IMRT respectively(32.06 ± 6.82 vs 35.39 ± 3.97,P=0.043;30.14± 7.97 vs 34.17±4.86,P=0.039;24.20±3.60 vs 25.47±3.90,P=0.254).No significant difference were found in R-Femoral head and L-Femoral head(20.38±2.22 vs 21.24±3.45,P=0.304;19.60±3.61 vs 22.41± 3.09,P=0.070).[Conclusion]1.The PTV coverage of HT plan was similar with IMRT plan.HT plan was significantly favored with regard to target conformity than IMRT plan.2.The V40(%)and Dmean of rectom,bladder,and bowel were obviously improved with HT over IMRT.Part II Dosimetry study of OAR between CT-ICBT and ICBT[ABSTRACT][Objective]To investigate the difference of OAR between CT-ICBT and ICBT[Method]47 patients with FIGO ?B-?B cervical cancer between January and December 2014 received concurrent chemoradiotherapy,dosimetry and clinical data were analyzed retrospectively.All patients received paclitaxel+cisplatin three weekly as the chemotherapy.22 patients were treated with CT-ICBT.25 patients were treated with ICBT.To describe the isodose curves,Rectom-DLeed wire,Rectom-DICRU and Bladder-DICRU of ICBT.To describe the isodose curves,Rectom-DLead wire,Rectom-DICRu and Bladder-DICRU of CT-ICBT.To compare the isodose curves,OAR,rectom total dose,and bladder total dose between 3D-plan and 2D-plan for CT-ICBT.[Results]1.The isodose curves,Rectom-D Lead wire,Rectom-DICRU and Bladder-DICRU of ICBT.Rectom-DICRU(Gy):3.14±0.62;Bladder-DICRU(Gy):3.000±0.36;Rectom-D Lead wire(Gy):2.00±0.38.2.The isodose curves,Rectom,DLead wire,Rectom-DICRU and Bladder-DICRu of CT-ICBT.Rectom-DICRU(Gy):3.93±0.88;Bladder-DICRU(Gy):4.32±0.78;Rectom-D Lead wire(Gy):2.53 ± 0.38.3.The isodose curves,OAR,rectom total dose,and bladder total dose between 3D-plan and 2D-plan for CT-ICBT.?D0.1cc(Gy):The dose of rectom and bladder were significantly higher in 3D-Plan than that in 2D-Plan respectively(4.11±0.65 vs 3.45±0.58,P=0.001;3.94 ± 0.74 vs 2.79 ± 0.55,P=0.001).D1cc(Gy):The dose of rectom and bladder were significantly higher in 3D-Plan than that in 2D-Plan respectively(3.46±0.38 vs 2.70±0.37,P=0.000;3.27 ± 0.42 vs 2.42 ± 0.38,P=0.001).D2cc(Gy):The dose of rectom and bladder were significantly higher in 3D-Plan than that in 2D-Plan respectively(3.16±0.66 vs 2.44±0.44,P=0.000;3.03 ±0.51 vs 2.27 ±0.45,P=0.001).?When the dose of point A reached 45-50Gy,the dose of rectom and bladder were significantly decreased in 3D-Plan than that in 2D-Plan respectively(26.500±4.24 vs 31.40±6.20,P=0.003;26.72±3.64 vs 30.013.60,P=0.003).[Conclusion]1.The dose of rectom and bladder were significantly higher in 3D-Plan than that in 2D-Plan.2.The dose of rectom and bladder were significantly decreased in CT-ICBT than that in ICBT,when the total dose of point A reached 45-50Gy.Part ? Clinicle study of HT+CT-ICBT and IMRT+ICBT in treatment of locally advanced cervical cancer[ABSTRACT][Objective]To investigate the difference of toxicity and survival between HT+CT-ICBT and IMRT+ICBT.[Method]47 patients with FIGO?B-?B cervical cancer between January and December 2014 received concurrent chemoradiotherapy,dosimetry and clinical data were analyzed retrospectively.All patients received paclitaxel+cisplatin three weekly as the chemotherapy.22 patients were treated with CT-ICBT.To compare acute toxicity,chronic toxicities,progression-free survival(PFS)and overall survival(OS)between HT+CT-ICBT group and IMRT+ ICBT group.[Results]1.Acute toxicity:No significant difference were found in hematologic,gastrointestinal,genitourinary,and cutaneous between HT+CT-ICBT and IMRT+ICBT.(P=1.000;P=0.423,P=0.670 P=1.000).2.Chronic toxicities:Proctitis and cystitis were significantly decreased in HT+CT-ICBT than that in IMRT+ ICBT respectively(P=0.033;P=0.050).3.PFS and OS:The 3 years PFS was 84.7%in HT+CT-ICBT,which was similar with IMRT+ ICBT(84.7%VS 77.4%,P = 0.782).The 3 years OS was 84.7%in HT+CT-ICBT,which was similar with IMRT+ ICBT(86.5%VS 78.3%,P = 0.596).[Conclusion]1.Chronic proctitis and cystitis were significantly decreased in HT+CT-ICBT group than that in IMRT+ 1CBT group.2.The 3 years PFS and OS in HT+CT-ICBT group were similar with IMRT+ ICBT group.