| Part ⅠA modified delineation method of para-aortic nodal clinical target volume in patients with locally advanced cervical cancerPurpose:To validate the nodal center coverage(NCC)of the three mainstream delineation methods of para-aortic nodal clinical target volume(CTV)and propose a modified delineation method of para-aortic nodal CTV in prophylactic extended-field radiation therapy(EFRT)of cervical cancer.Methods and Materials:A total of 106 patients with para-aortic lymph nodes(PALNs)identified on PET/CT were included at our institute between 2011 and 2020.PALNs were classified as left lateral para-aortic(LLPA),aorto-caval(AC),and right para-caval(RPC).Distances from the nodal center to the aorta and inferior vena cava(IVC)were measured.The NCC of the three mainstream delineation methods of para-aortic nodal CTV(CTV-K,CTV-S,and CTV-D)and a modified CTV(CTV-M)were calculated.Radiotherapy plans were created based on 4 CTVs for 10 selected patients who received prophylactic EFRT.The chi-squared test and Student’s t-test were performed.Results:We identified 344 PALNs(216 LLPA,101 AC,27 RPC)in 106 patients.Mean distance from the nodal center to the aorta was 9.6 mm in the LLPA and 7 mm in the AC and from the nodal center to the IVC was 5.6 mm in the AC and 5.6 mm in the RPC.CTVD improved the NCC of 98%compared with 92%for CTV-K(P=0.002)and 95%for CTV-S(P=0.046).CTV-M provided the same satisfactory NCC as CTV-D(97%vs 98%,P=0.485).The V50Gy to the duodenum,the Dmean to the bilateral kidneys,and the V45Gy to the small bowel were significantly lower on the CTV-M-based plan than on the CTV-Dbased plan(P=0.001,0.011,and 0.001,respectively).Conclusions:CTV-D provided more satisfactory NCC than CTV-K and CTV-S.CTV-M provided the same satisfactory NCC as CTV-D and reduced the dose to the critical structures.Part ⅡHigher dose to organs at risk:the unintended consequences of intravenous contrast use in computed tomography simulation for cervical cancerPurpose:To compare the volumes of interest and doses to the organs at risk on contrast and noncontrast scans in patients with cervical cancer who underwent prophylactic extended-field radiation therapy(EFRT).Methods and Materials:We reviewed twenty cervical cancer patients treated with prophylactic EFRT at our institute between March 2021 and April 2021.Each patient underwent noncontrast and contrast scans during simulation.All structures were contoured,and radiation therapy plans were created based on both scans.Student t test and Pearson correlation coefficient test were performed.Results:Compared with the noncontrast scan,on the contrast scan,the mean volume of the inferior vena cava expanded by 44%(P≤0.001),and the mean volume of the paraaortic nodal clinical target volume increased by 17%(P≤0.001).For the second portion of the duodenum,the V30(38.2%vs 43.8%,P=0.038),V35(27.6%vs 35.1%,P=0.002),V40(18.3%vs 26.3%,P=0.014),V45(11.2%vs 18.5%,P=0.008),and V50(4.2%vs 9.1%,P=0.005)were significantly lower on the noncontrast scan than on the contrast scan.For the third portion of the duodenum,the V45(78.4%vs 81.6%,P=0.03)and V50(59.7%vs 67%,P≤0.001)were significantly lower on the noncontrast scan than on the contrast scan.For the right kidney,the V5,V10,V15,V20,and V25 on the contrast and noncontrast scans were 85.4%versus 79.8%(P=0.013),52.5%versus 45.6%(P=0.021),25.6%versus 20.1%(P=0.003),11.1%versus 7.5%(P=0.001),and 3.8%versus 2.3%(P=0.027),respectively.Conclusions:Compared with the noncontrast scan,expansion of the inferior vena cava on the contrast scan can lead to excessive contouring and an overdose to the duodenum and right kidney in cervical cancer patients treated with prophylactic EFRT.Part ⅢPelvic radiation therapy versus prophylactic extended-field radiation therapy in locally advanced cervical cancer patients with high-risk factorsPurpose:To compare the survival outcomes and toxicities between pelvic radiation therapy(PRT)and prophylactic extended-field radiation therapy(EFRT)in locally advanced cervical cancer(LACC)patients with high-risk factors.Methods and Materials:This was a multicenter,open-label,phase 3 randomized clinical trial,registered with ClinicalTrials.gov,identifier:NCT03955367.In this study,LACC patients with negative para-aortic lymph nodes and at least one of the following high-risk factors were enrolled:the number of positive pelvic lymph nodes(PLNs)≥2 or short diameter of PLNs ≥1.5 cm or tumor extension to the pelvic wall.Eligible patients were randomly assigned in a 1:1 ratio to receive PRT or EFRT.Concurrent chemoradiotherapy was the standard treatment for LACC patients.Kaplan-Meier methods,log-rank test,and chi-squared test were performed.Results:Between July 2019 to September 2021,50 patients were enrolled at our institute,of whom 25 were assigned to receive PRT and 25 were assigned to receive EFRT.The median follow-up period was 18 months.There was no significant difference in baseline characteristics between the two groups.In the intention-to-treat analysis,1-year progression free survival(PFS),overall survival(OS),distance metastasis free survival(DMFS),and para-aortic lymph node failure(PALNF)were 75.3%vs 73.7%(P=0.733),95.5%vs 95.7%(P=0.732),86.9%vs 87.2%(P=0.961),and 4.7%vs 4.4%(P=0.520)in the PRT group and EFRT group,respectively.In the per-protocol analysis,1-year PFS,OS,DMFS,and PALNF were 80.7%vs 74.3%(P=0.989),95%vs 100%(P=0.915),90.2%vs 89.8%(P=0.962),and 5.1%vs 5.1%(P=0.538)in the PRT group and EFRT group,respectively.In the subgroup analysis,no significant difference was observed concerning 1-year PFS,OS,DMFS,and PALNF between the two groups for patients with positive PLNs≥2 or short diameter of PLNs ≥1.5 cm or tumor extension to the pelvic wall or one high-risk factor or 2-3 high-risk factors.There was no significant difference concerning G3-4 acute and late toxicities between the two groups.No patients died from treatment-related toxicities.Conclusions:Compared with the PRT group,no survival outcomes benefit was observed in the EFRT group for LACC patients with high-risk factors.Given the small sample size and the short follow-up period,this conclusion should be regarded with caution. |
PDF Full Text Request