Prognostic factors and failure patterns in non-metastatic nasopharyngeal carcinoma after intensity-modulated radiotherapy

Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of non?meta?static nasopharyngeal carcinoma(NPC) in the intensity?modulated radiotherapy(IMRT) era.Methods: We reviewed the data from 749 patients with newly diagnosed, biopsy?proven, non?metastatic NPC in our cancer center(South China, an NPC endemic area) between January 2003 and December 2007. All patients under?went magnetic resonance imaging(MRI) before receiving IMRT. The actuarial survival rates were estimated using the Kaplan–Meier method, and survival curves were compared using the log?rank test. Multivariate analyses with the Cox proportional hazards model were used to test for the independent prognostic factors by backward eliminating insigniicant explanatory variables.Results: The 5?year occurrence rates of local failure, regional failure, locoregional failure, and distant failure were 5.4, 3.0, 7.4, and 17.4%, respectively. The 5?year survival rates were as follows: local relapse?free survival, 94.6%; nodal relapse?free survival, 97.0%; distant metastasis?free survival, 82.6%; disease?free survival, 75.1%; and overall survival, 82.0%. Multivariate Cox regression analysis revealed that orbit involvement was the only signiicant prognostic fac?tor for local failure(P = 0.011). Parapharyngeal tumor extension, retropharyngeal lymph node involvement, and the laterality, longest diameter, and Ho's location of the cervical lymph nodes were signiicant prognostic factors for both distant failure and disease failure(all P < 0.05). Intracranial extension had signiicant prognostic value for distant failure(P = 0.040).Conclusions: The key failure pattern for NPC was distant metastasis in the IMRT era. With changes in diagnostic and therapeutic technologies as well as treatment modalities, the signiicant prognostic parameters for local control have also been altered substantially.

Intensity-modulated radiotherapy for breast cancer:a systematic review

Objective:The aim of this study was to assess the long-term effect of breast conservation with breast intensitymodulated radiotherapy (IMRT) for early-stage breast cancers.Methods:Pub Med,EMBASE,Cochrane Library,Chinese Biomedical Literature Database were searched to identify relevant original published trails,and the references of eligible studies were manually screened.Randomized controlled trails reported in any language,comparing breast IMRT with conventional radiotherapy (RT) in patients with early-stage breast cancer were eligible for inclusion.Two investigators independently assessed the quality of included trials and extracted data.The RevMan 5.0 software was used for statistical analysis.Results:Four trials involving 1440 patients were included.The results showed that in the IMRT group,the occurrence of acute moist dermatitis,the edema of the mammary gland and the occurrence of hyperpigmentation were lower than those of RT group,the pooled risk ratio value and 95% confidence interval were 0.28 (0.17-0.48),0.03 (0.00-0.21) and 0.06 (0.02-0.15) respectively.The use of IMRT did not correlate with pain and quality of life,but the presence of moist desquamation did significantly correlate with pain and reduced quality of life.Conclusion:The currently available evidence showed that IMRT significantly reduces the occurrence of moist acute dermatitis anywhere in the breast and alleviates the suffering of patients and improves the quality of life of patients.Future large-scale,high-quality,double-blind trials are needed.

Prognostic value and predictive threshold of tumor volume for patients with locally advanced nasopharyngeal carcinoma receiving intensity-modulated radiotherapy

Background: Gross target volume of primary tumor(GTV?P) is very important for the prognosis prediction of patients with nasopharyngeal carcinoma(NPC), but it is unknown whether the same is true for locally advanced NPC patients treated with intensity?modulated radiotherapy(IMRT). This study aimed to clarify the prognostic value of tumor volume for patient with locally advanced NPC receiving IMRT and to ind a suitable cut?of value of GTV?P for prognosis prediction.Methods: Clinical data of 358 patients with locally advanced NPC who received IMRT were reviewed. Receiver oper?ating characteristic(ROC) curves were used to identify the cut?of values of GTV?P for the prediction of diferent end?points [overall survival(OS), local relapse?free survival(LRFS), distant metastasis?free survival(DMFS), and disease?free survival(DFS)] and to test the prognostic value of GTV?P when compared with that of the American Joint Committee on Cancer T staging system.Results: The 358 patients with locally advanced NPC were divided into two groups by the cut?of value of GTV?P as determined using ROC curves: 219(61.2%) patients with GTV?P ≤46.4 mL and 139(38.8%) with GTV?P >46.4 mL. The 3?year OS, LRFS, DMFS, and DFS rates were all higher in patients with GTV?P ≤46.4 mL than in those with GTV?P > 46.4 mL(all P < 0.05). Multivariate analysis indicated that GTV?P >46.4 mL was an independent unfavorable prognostic factor for patient survival. The ROC curve veriied that the predictive ability of GTV?P was superior to that of T category(P < 0.001). The cut?of values of GTV?P for the prediction of OS, LRFS, DMFS, and DFS were 46.4, 57.9, 75.4 and 46.4 mL, respectively.Conclusion: In patients with locally advanced NPC, GTV?P >46.4 mL is an independent unfavorable prognostic indi?cator for survival after IMRT, with a prognostic value superior to that of T category.

Significant value of 18F-FDG-PET/CT in diagnosing small cervical lymph node metastases in patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy

Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT).The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.Methods: Magnetic resonance images(MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.Results: In total, 2082 SCLNs were identified, with 808(38.8%) ≥ 5 and < 6 mm in diameter(group A), 526(25.3%)≥ 6 and < 7 mm in diameter(group B),374(18.0%)≥ 7 and < 8 mm in diameter(group C), 237(11.4%) ≥8 and<9 mm in diameter(group D),and 137(6.5%) ≥ 9 and <10 mm in diameter(group E).The overall metastatic rates examined by using PET/CT for groups A, B,C,D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively(P< 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135(28.7%) and 46(9.8%) patients, respectively. The areas under curve of MRIdetermined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.Conclusions: PET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined.

A model to predict the risk of lethal nasopharyngeal necrosis after re-irradiation with intensity-modulated radiotherapy in nasopharyngeal carcinoma patients

Background:For patients with nasopharyngeal carcinoma(NPC) who undergo re-irradiation with intensity-modulated radiotherapy(IMRT),lethal nasopharyngeal necrosis(LNN) is a severe late adverse event.The purpose of this study was to identify risk factors for LNN and develop a model to predict LNN after radical re-irradiation with IMRT in patients with recurrent NPC.Methods:Patients who underwent radical re-irradiation with IMRT for locally recurrent NPC between March 2001 and December 2011 and who had no evidence of distant metastasis were included in this study.Clinical characteristics,including recurrent carcinoma conditions and dosimetric features,were evaluated as candidate risk factors for LNN.Logistic regression analysis was used to identify independent risk factors and construct the predictive scoring model.Results:Among 228 patients enrolled in this study,204 were at risk of developing LNN based on risk analysis.Of the 204 patients treated,31(15.2%) developed LNN.Logistic regression analysis showed that female sex(P = 0.008),necrosis before re-irradiation(P = 0.008),accumulated total prescription dose to the gross tumor volume(GTV) ≥ 145.5 Gy(P = 0.043),and recurrent tumor volume >25.38 cm3(P = 0.009) were independent risk factors for LNN.A model to predict LNN was then constructed that included these four independent risk factors.Conclusions:A model that includes sex,necrosis before re-irradiation,accumulated total prescription dose to GTV,and recurrent tumor volume can effectively predict the risk of developing LNN in NPC patients who undergo radical re-irradiation with IMRT.

Clinical treatment considerationsin the intensity-modulated radiotherapy era for patients with NO-category nasopharyngeal carcinoma and enlarged neck lymph nodes

Background:Nasopharyngeal carcinoma(NPC) shows a high proportion of lymph node metastasis,and treatment guidelines have been developed for positive nodes.However,no irradiation guidelines have been proposed for patients with enlarged neck lymph nodes(ENLNs) that do not meet the radiological criteria of 10 mm in diameter for positive lymph nodes.This study aimed to determine the prognostic value and radiation dose for ENLNs in NO-category NPC patients treated with intensity-modulated radiotherapy(IMRT).Methods:We reviewed the medical data of 251 patients with non-metastatic,NO-category NPC treated with IMRT.Receiver operating characteristic curves were used to calculate the cut-off value of the ENLN diameter for the prediction of disease failure.The biological equivalent dose(BED) for ENLNs was calculated.Patient survival was compared between the small and large ENLN groups.Independent prognostic factors were identified using the Cox proportional hazards model.Results:The estimated 4-year regional relapse-free survival rate was higher in patients with ENLNs ≥5.5 mm than in those with ENLNs <5.5 mm(100%vs.98.8%,P=0.049),whereas disease-free,overall,and distant metastasis-free survival rates were similar between the two groups.After adjusting for various factors,ENLN diameter was not identified as an independent prognostic factor(P > 0.05 for all survival rates).In the subgroup analysis,patients receiving BED ≥72 Gy had a similar prognosis as patients receiving BED <72 Gy in both the small and large ENLN groups.The multivariate analysis also confirmed that BED≥72 Gy was not associated with significantly improved prognosis in patients with NO-category NPC.Conclusions:A BED of 72 Gy to ENLNs is considerably sufficient to provide a clinical benefit to patients with NO-category NPC.Prospective studies are warranted to validate the findings in the present study.

Intensified intensity-modulated radiotherapy in anal cancer with prevalent HPV p16 positivity

AIM: To investigate the toxicity and response of intensity-modulated radiotherapy schedule intensified with a simultaneous integrated boost in anal canal cancer.METHODS: From March 2009 to March 2014, we retrospectively analyzed 41 consecutive patients treated with intensity-modulated radiotherapy(IMRT) and concurrent chemotherapy for anal canal squamous cell carcinoma at our center. Radiotherapy was delivered via simultaneous integrated boost(SIB) technique by helical tomotherapy, and doses were adapted to two clinical target volumes according to the tumor-nodemetastasis(TNM) stage: 50.6 Gy and 41.4 Gy in 23 fractions in T1N0, 52.8 Gy and 43.2 Gy in 24 fractionsin T2N0, and 55 Gy and 45 Gy in 25 fractions in all patients with N positive and/or ≥ T3, respectively, to planning target volumes 1 and 2. The most common chemotherapy regimen was 5-fluorouracil and mitomycin-based. Human papilloma virus(HPV) p16 expression was performed by immunohistochemistry and evaluated in the majority of patients. Acute and late toxicity was scored according to CTCAe v 3.0 and RTOG scales.RESULTS: The median follow-up was 30 mo(range:12-71). Median age was 63 years(range 32-84). The stage of disease was: stage Ⅰ in 2 patients, stage Ⅱin 13 patients, stage ⅢA in 12 patients, and stage ⅢB in 14 patients, respectively. Two patients were known to be HIV positive(4.9%). HPV p16 expression status was positive in 29/34(85.3%) patients. The 4-year progression-free survival and overall survival in HPVpositive patients were 78% and 92%, respectively.Acute grade 3 skin and gastrointestinal toxicities were reported in 5% and 7.3% of patients, respectively;patients' compliance to the treatment was good due to a low occurrence of severe acute toxicity, although treatment interruptions due to toxicity were required in 7.3% of patients. At 6 mo from end of treatment,36/40(90%) patients obtained complete response;during follow-up, 5(13.8%) patients presented with disease progression(local or systemic).CONCLUSION: In our experience, intensified SIBIMRT with chemotherapy is very feasible in clinical practice, with excellent results in terms of overall survival and local control.

Dosimetric study of five-field intensity-modulated radiotherapy compared with conventional three-dimensional conformal radiotherapy for rectal cancer

Objective： The aim of the study was to compare the difference of dose distribution in clinical target volume and organ at risk （OAR） between five-field intensity-modulated radiotherapy （IMRT） and conventional three-dimensional conformal radiotherapy （3DCRT） in the radiotherapy of rectal cancer. Methods： Fifteen patients with rectal cancer treated with radio- therapy （RT） were retrospectively analyzed. Among the patients, seven received RT preoperatively and 8 postoperatively. The target volume and the OARs such as the small bowel, bladder and femoral heads were contoured for each patient. 3DCRT-plan and IMRT-plan were performed for each patient respectively, with the prescribed dose covering at least 95% of the planning target volume （PTV）. The conformity index （CI） and homogeneity index （HI） were used for evaluation of the dose distribution in the target volume, and the Dx% （the lowest dose to the x% volume of the OARs that received the highest dose of irradiation） and the mean dose were used for evaluation of the dose to OARs. Paired-T test was used for companson of the difference between the two plans. Results： In the IMRT-plan and 3DCRT-plan, the CI were 0.94 and 0.87 （P = 0.000） and the HI were 1.13 and 1.17, respectively （P = 0.001）. For small bowel, the D30%, D50% and the mean dose were 19.67 Gy, 15.13 Gy and 18.81 Gy in the IMRT-plan and 25.20 Gy, 22.20 Gy and 22.89 Gy in the 3DCRT-plan, respectively （P 〈 0.001 for all pairs of parameters）. For bladder, the D30%, D50%, and the mean dose were 24.80 Gy, 34.20 Gy and 28.70 Gy in the IMRT- plan, and 35.07 Gy, 44.67 Gy and 35.68 Gy in the 3DCRT-plan, respectively （P 〈 0.001 for all pairs of parameters）. For femoral heads, the D5% in the IMRT-plan and 3DCRT-plan were 40.6 Gy and 40.47 Gy, respectively （P = 0.936）, and the mean dose were 30.14 Gy and 25.57 Gy, respectively （P = 0.001）. Conclusion： Five-field IMRT-plan is better than 3DCRT-plan in the conformity and the dose homogeneity within target volume and also better in sparing the small bowel and bladder.

Dosimetric consequences of tumor volume changes after kilovoltage cone-beam computed tomography for non-operative lung cancer during adaptive intensity-modulated radiotherapy or fractionated stereotactic radiotherapy

Objective The aim of this study was to investigate tumor volume changes with kilovoltage cone-beam computed tomography （kV-CBCT） and their dosimetric consequences for non-operative lung cancer during intensity-modulated radiotherapy （IMRT） or fractionated stereotactic radiotherapy. Methods Eighteen patients with non-operative lung cancer who received IMRT consisting of 1.8-2.2 Gy/fraction and five fractions per week or stereotactic radiotherapy with 5-8 Gy/fraction and three fractions a week were studied, kV-CBCT was performed once per week during IMRT and at every fraction during stereotactic radiotherapy. The gross tumor volume （GTV） was contoured on the kV-CBCT images, and adaptive treatment plans were created using merged kV-CBCT and primary planning computed tomogra- phy image sets. Tumor volume changes and dosimetric parameters, including the minimum dose to 95% （D95） or 1% （D1） of the planning target volume （PTV）, mean lung dose （MLD）, and volume of lung tissue that received more than 5 （Vs）, 10 （Vl0）, 20 （V20）, and 30 （V30） Gy were retrospectively analyzed. Results The average maximum change in GTV observed during IMRT or fractionated stereotactic radio- therapy was -25.85% （range, -13.09% --56.76%）. The D95 and Dr of PTV for the adaptive treatment plans in all patients were not significantly different from those for the initial or former adaptive treatment plans. In patients with tumor volume changes of 〉20% in the third or fourth week of treatment during IMRT, adap- tive treatment plans offered clinically meaningful decreases in MLD and V5, V10, V20, and V30; however, in patients with tumor volume changes of 〈 20% in the third or fourth week of treatment as well as in patients with stereotactic radiotherapy, there were no significant or clinically meaningful decreases in the dosimetric parameters. Conclusion Adaptive treatment planning for decreasing tumor volume during IMRT may be beneficial for patients who experience tumor volume changes of 〉20% in the third or fourth week of treatment.

Dosimetric analysis of tomotherapy-based intensity-modulated radiotherapy with and without bone marrow sparing for the treatment of cervical cancer

Objective The aim of the study was to compare tomotherapy-based bone marrow-sparing intensity-mod- ulated radiotherapy （BMS-IMRT） with intensity-modulated radiotherapy （IMRT） without entering the pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods BMS-IMRT and IMRT plans were designed for a cohort of nine patients. The prescribed dose was 45 Gy in 1.8 Gy daily fractions, and 95% of the planned target volume received this dose. The doses were computed using a commercially available treatment planning system with the convolution/superposition algorithm. Plans were compared according to dose-volume histogram analysis in terms of planning target volume homogeneity and conformity indices （HI and CI） as well as organ at risk dose and volume parameters. Results BMS-IMRT had advantages over IMRT in terms of CI, but was equivalent to the latter in H1. V5, V10, V20, V30, and V40 of pelvic bone marrow in BMS-IMRT decreased by 0.06%, 17.33%, 22.19%, 13.85%, and 16.46%, respectively, compared with IMRT. Except for V30 of the small bowel and V30 and V40 of the bladder, no statistically significant differences were found between BMS-IMRT and IMRT in the small bowel, bladder, and rectum. Conclusion For cervical cancer patients receiving tomotherapy-based radiotherapy after hysterectomy, BMS-IMRT reduced pelvic bone marrow volume receiving low-dose radiation, and it may be conducive to preventing acute hematologic toxicity.

Dosimetric Comparative Analysis of Volumetric Modulated Arc Therapy and Intensity-Modulated Radiation Therapy in Cervical Cancer

Objective:To carry out dosimetric comparison between volumetric modulated arc therapy(VMAT)and intensity-modulated radiation therapy(IMRT)in cervical cancer.Methods:50 postoperative cervical cancer patients were included in this study.The patients were admitted for treatment from January 2021 to January 2022.VMAT and IMRT plans were designed for each patient to analyze the dose distribution in the target area of the two treatment techniques.Results:Comparing the monitor unit for single treatment(638.21±116.21 MU)and time of single treatment(143.21±23.14 s)in the observation group and the monitor unit for single treatment(932.14±74.11 MU)and time of single treatment(223.14±17.26 s)in the control group,there was significant difference(P<0.05);there was also significant difference(P<0.05)between the normal tissue(bladder and rectum)of the observation group and that(bladder and rectum)of the control group.Conclusion:VMAT is more effective in cervical cancer,and it has a certain protective effect on normal tissues in patients and can reduce the radiation dose.

COMBINATION OF PRONE POSITION AND INTENSITY-MODULATED RADIATION THERAPY (IMRT) REDUCES SMALL BOWEL DOSES IN RADIATION THERAPY FOR GYNECOLOGIC MALIGNANCIES

Objective： To evaluate if the combination of both prone position on a belly board and intensity-modulated radiotherapy （IMRT） further reduces the radiation dose to small bowel in pelvic RT for gynecologic malignancies. Methods： Conformal pelvic RT plans were computed in 13 patients with gynecologic malignancies who had pre-existing planning computed tomography （CT） scans in both the supine position and prone position on a belly board. There were 10 cervical cancer and 3 endometrial cancer patients. A limited arc technique （180° arc length） and an extended arc technique （340° arc length） were used in IMRT plans. Normal tissue regions of interest （ROI） included small bowel, large bowel and bladder. Dose and volume for normal tissue structures were traced and compared between supine and prone plans using the paired t-test. Results： For the limited arc technique, prone position using a belly board device improved small bowel sparing. Analysis of the results showed a 12~26 Gy reduction of volume of small bowel irradiation compared to the supine position. With the extended arc technique, there was no obvious radiation reduction in the prone position. Large bowel and bladder dose showed no significant differences between prone and supine position with either technique. Conclusion： Prone positioning on a belly board decreases the small bowel dose in gynecologic pelvic IMRT, and the magnitude of improvement depended on the limited arc IMRT technique used.

The Effect of Treatment Position on Rectal and Bladder Dose-Volume Histograms for Prostate Radiotherapy Planned with 3-Dimensional Conformal Radiotherapy, Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy

Purpose: To compare target coverage and organ at risk (OAR) sparing in the supine and prone positions with 3-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in low- and high-risk prostate radiotherapy cases. Materials and Methods: Using magnetic resonance images of five healthy volunteers, six treatment plans (supine 3DCRT, prone 3DCRT, supine IMRT, prone IMRT, supine VMAT and prone VMAT) were generated. Planning target volume 1 (PTV1) was defined as the prostate gland plus the seminal vesicles with adequate margins in a high-risk setting, while PTV2 was defined as prostate only with margins in a low-risk setting. The mean dose for both PTV1 and PTV2 was set at 78 Gy. Plans generated by each of the 3 techniques were compared between the supine and prone positions using dose-volume histograms (DVHs). Results: For PTV1, prone 3DCRT provided a significantly higher D98% than did supine 3DCRT, and its homogeneity index (HI) was significantly better. IMRT and VMAT values did not differ significantly between the prone and supine positions. For PTV2, no values differed significantly between the supine and prone positions under any treatment plan. With respect to OAR, the rectal D mean, D2%, V50, and V60 values of PTV1 were statistically higher in supine 3DCRT than in prone 3DCRT, while there were no significant differences in rectal values between the supine and prone positions with IMRT or VMAT. The rectal Dmean, V50, V60, V70, and V75 values of prone 3DCRT were significantly higher than those of supine IMRT or supine VMAT. There were no significant differences in any values for the rectum and bladder for PTV2. Conclusion: Although prone 3DCRT was found to be superior to supine 3DCRT in terms of rectal sparing in high-risk prostate cancer, IMRT and VMAT techniques could possibly cover this disadvantage.

Intensity-modulated Radiotherapy for Sinonasal Teratocarcinosarcoma

Surgical excision and postoperative radiotherapy are widely accepted therapeutic modalities for sinonasal teratocarcinosarcoma （SNTCS）. Previous studies have shown that intensity-modulated radiation therapy （IMRT） is safe and effective for the treatment of some sinonasal malignancies. We hypothesize that use of IMRT for SNTCS may result in clinical benefits. We report here two cases of SNTCS that were treated by IMRT. One patient was given extensive IMRT involving elective neck irradiation. Follow-up examinations revealed no recurrence and metastasis 3.5 years after IMRT. Another patient simultaneously suffered from multiple systematical diseases and was administered involved-field radiotherapy. He was found to have a marginal recurrence during the follow up and eventually died 8 months after disease diagnosis. It was suggested in this study that appropriate use of IMRT for the treatment of SNTCS may achieve excellent local control.

Bone marrow-sparing intensity-modulated radiotherapy for postoperative treatment of cervical cancer

Objective： The aim of this study was to compare bone marrow-sparing intensity-modulated radiotherapy （IMRT） with IMRT without entering pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods： For a cohort of 10 patients, bone marrow-sparing IMRT and routine IMRT planning were designed. The prescribed dose was 45 Gy/1.8 Gy/25f, 95% of the planning target volume received this dose. Doses were computed with a commercially available treatment planning system （TPS） using convolution/superimposition （CS） algorithm. Plans were compared according to dose-volume histogram （DVH） analysis in terms of planning target volume （PTV） homogeneity and conformity indices （HI and CI） as well as organs at risk （OARs） dose and volume parameters. Results： Bone marrow-sparing IMRT had an vantages over routine IMRT in terms of CI, but inferior to the latter for HI. Compared with routine IMRT, V5, Vl0, V20, V30, V40 of pelvic bone marrow of bone marrow-sparing IMRT reduced by 1.81%, 8.61%, 31.81%, 29.50%, 28.29%, respectively. No statistically significant differences were observed between bone marrow-sparing IMRT and routine IMRT in terms of small bowel, bladder and rectum. Conclusion： For patients with cervical cancer after hysterectomy, bone marrowsparing IMRT reduced the pelvic bone marrow volume irradiated at all dose levels and might be conducive to preventing the occurrence of acute bone marrow toxicity.

Observation of Intensity-Modulated Radiotherapy with Different Fractionated Doses Used in 58 Cases with Astrocytoma

OBJECTIVE To analyze the therapeutic effects and side effects of intensity-modulated radiotherapy （IMRT） with different fractionated doses in treating astrocytoma.METHODS During a period from October 2001 to December 2006, 58 patients with astrocytoma were treated using IMRT. Based on the World Health Organization （WHO） classification, 32 of the 58 cases were grade-Ⅱ, 20 grade-Ⅲ and 6 grade-IV （glioblastoma multiforme, GBM）. Thirty-two of the 58 patients （3 with grade IV, 11 with grade Ⅲ, and the other 18 with grade II who were over 40 years） were treated with hyperfractionated IMRT （Hyper Fr IMRT）, and the other 26 patients were treated with standard fractionated IMRT （St Fr IMRT）.RESULTS The 1-, 3- and 5-year overall survival （OS） rates were respectively 86%, 52%, and 45%, and the 1-, 3- and 5-year progression-free survival （PFS） rates were respectively 77%, 38%, and 25%. Using an analytical hierarchy process it was shown that concerning the patients with grade II astrocytoma classified based on WHO grading, the therapeutic effect was much better in the group of Hyper Fr IMRT than in the St Fr IMRT group. There was no statistical significance of the differences in the OS and PFS rates between the 2 groups （P = 0.049 and P = 0.006）. The OS and PFS rates of the patients with grade-III astrocytoma were both higher in the group with Hyper Fr IMRT than in the St Fr IMRT group. However, there was no statistical significance of the differences between the 2 groups. Advanced RTOG grade-Ⅲ（radiation therapy oncology group, RTOG） neurotoxicity occurred only in 1 of the cases.CONCLUSION Compared with the St Fr IMRT, the Hyper Fr IMRT may help to prolong the survival of patients with astrocytoma.

基于VMAT和IMRT在宫颈癌根治放疗中的剂量学差异分析

目的:探讨容积旋转调强放疗(VMAT)和逆向调强放疗技术(IMRT)在宫颈癌根治放疗中的剂量学差异。方法:选取2020年1月至2022年12月在我院治疗的51例宫颈癌患者为研究对象,对所有患者进行IMRT和VMAT放疗设计。比较两种放疗技术的靶区剂量、机器跳数、治疗时间以及危及器官剂量分布。结果:VMAT的适形度指数(CI)高于IMRT,均匀性指数(HI)低于IMRT,差异有统计学意义(P<0.05)。VMAT技术的机器跳数少于IMRT,治疗时间短于IMRT,差异有统计学意义(P<0.05)。危及器官剂量分布比较结果显示,股骨头剂量分布中,VMAT的V_(20)、D_(mean)低于IMRT;小肠和盆骨骨髓的剂量分布中,VMAT的V_(20)、V_(30)、D_(mean)低于IMRT;直肠剂量分布中,VMAT的V_(20)低于IMRT;膀胱剂量分布中,VMAT的D_(mean)低于IMRT;差异均有统计学意义(P<0.05)。结论:VMAT可以获得与IMRT相当的靶区剂量分布,而且VMAT的靶区适形度、剂量均匀性更佳,更利于保护危及器官。

Effect of intensity-modulated radiotherapy combined with local hyperthermia on Mortalin expression in advanced liver cancer lesions and its relationship with cell proliferation and EMT

Objective:To investigate the effect of intensity-modulated radiotherapy combined with local hyperthermia on Mortalin expression in advanced liver cancer lesions and its relationship with cell proliferation and EMT.Methods: A total of 82 patients with advanced liver cancer who were treated in this hospital between February 2016 and September 2017 were chosen as the research subjects, and the therapeutic regimens were reviewed and used to divide these patients into the control group (n=43) who received intensity-modulated radiotherapy and the combined treatment group (n=39) who received intensity-modulated radiotherapy combined with local hyperthermia. Abdominal puncture was done after treatment to obtain liver cancer tissue samples, and the differences in Mortalin gene, cell proliferation gene and EMT gene expression in tissues were compared.Results: After treatment, Mortalin mRNA expression in liver cancer tissues of combined treatment group was lower than that of control group;Fbxw7 mRNA expression in liver cancer tissues was higher than that of control group whereas NCX1, PRMT5 and XBP1S mRNA expression were lower than those of control group;Twist, ZEB-1, ZEB-2, Snail and HOXB7 mRNA expression in liver cancer tissues were lower than those of control group. Pearson test showed that the Mortalin gene expression in liver cancer tissues was directly correlated with cell proliferation genes and EMT genes.Conclusion:Intensity-modulated radiotherapy combined with local hyperthermia can effectively reduce Mortalin gene expression, and further optimize patients'condition by inhibiting hepatic cell proliferation, EMT activity and other pathways.

不可手术食管癌患者序贯加量IMRT与同步推量IMRT的剂量学比较分析

目的对比不可手术食管癌序贯加量调强放射治疗(SB-IMRT)计划与同步推量调强放射治疗(SIB-IMRT)计划在靶区参数上的区别,以及对正常器官的影响程度。方法选择日照市人民医院2018年10月至2022年5月拟行放射治疗的不可手术食管癌患者30例,其中男性25例,女性5例;年龄60~88岁,中位年龄68.2岁;病变长度4.0~17.6 cm,平均病变长度6.37 cm(标准差2.76 cm);临床分期为c Tx N1-2M0-1期。分别制定SB-IMRT与SIB-IMRT两种放射治疗计划,并采用靶区勾画、射束设野、靶区覆盖、剂量均匀性、危及器官(OAR)、处方剂量(CB-CHOP)审核通过放射治疗计划。SIB-IMRT给予剂量方法为在一个计划中临床计划靶区(PCTV)50.4 Gy,肿瘤计划靶区(PGTV)剂量同步给予59.92 Gy,共28次完成。SB-IMRT剂量要求为PCTV 50 Gy,均分25次完成;完成后修改照射野局部加照至10 Gy,均分5次完成。SB-IMRT放射治疗需设计前后两套计划,再做计划叠加处理,合成一套计划后根据处方剂量要求优化计划并记录靶区参数和OAR限量。采用均匀性指数(HI)、适形性指数(CI)、靶区覆盖度(TC)及剂量分布、OAR限量等参数分别评估。结果两组计划的PCTV-Dmax、PGTV-Dmax和PCTV-Dmin剂量差异无统计学意义(均P>0.05),但SIB-IMRT组PCTV-Dmean、PGTV-Dmin、PGTV-Dmean均低于SB-IMRT组,差异有统计学意义[(57.38±1.73)Gy vs(58.13±2.38)Gy、(51.41±4.90)Gy vs(54.76±6.31)Gy、(61.22±2.10)Gy vs(62.86±2.03)Gy。P>0.05]。两组计划的PCTV-TC值比较,差异无统计学意义(P>0.05)。SB-IMRT组CI优于SIB-IMRT组,而HI次于SB-IMRT组,两组间CI、HI值比较,差异有统计学意义(0.55±0.10 vs 0.60±0.11、1.20±0.38 vs 1.24±0.39。P<0.05)。SIB-IMRT组PGTV和PCTV的生物效应剂量(BED)分别为72.74 Gy、59.47 Gy;SB-IMRT组PGTV和PCTV的BED分别为72 Gy、60 Gy。SIB-IMRT组脊髓Dmax、双肺V5和心脏的平均心脏剂量(MHD)低于SB-IMRT组,差异均有统计学意义[(41.83±2.48)Gy vs(43.27±1.99)Gy、(41.06±11.74)Gy vs(42.26±11.52)Gy、(20.77±8.81)Gy vs(22.72±9.23)Gy。P<0.05]。双肺V_(10)、V_(20)、V_(30)、平均肺剂量(MLD)和心脏V_(30)、V40两组间比较,差异无统计学意义(P>0.05)。结论在不可手术食管癌放射治疗中,相似或/和相等处方剂量的SB-IMRT计划和SIB-IMRT计划,前者仅CI略占优势,后者计划一次成型,能同时给予肿瘤靶区和临床预防靶区不同梯度的剂量照射,具有高效、精确,生物效应高、OAR受照剂量更低的优势,值得临床推广。

Selective partial salivary glands sparing during intensity-modulated radiation therapy for nasopharyngeal carcinoma

Objective This study evaluated the dosimetric consequences of selective partial salivary gland sparing during intensity-modulated radiotherapy(IMRT) for patients with nasopharyngeal carcinoma(NPC).Methods Ten patients with NPC were enrolled in the study.Two IMRT plans were produced for each patient:conventional(control) and partial salivary glands-sparing(treatment),with dose constraints to the entire parotid glands or partial salivary glands(including the parotid and submandibular glands,delineated with the adjacent distance of at least 0.5 cm between the glands and PTV,the planning target volume) in planning,respectively.Dosimetric parameters were compared between the two plans,including the V_(110%),V_(100%),V_(95%)(the volume covered by more than 110%,100%,or 95% of the prescribed dose),Dmin(the minimum dose) of PTV,homogeneity index(HI),conformity index(CI),and the mean dose and percentage of the volume receiving 30 Gy or more(V_(30)) for the parotid glands and submandibular glands.Results Treatment plans had significantly lower mean doses and V_(30) to both the entire parotid glands and partial parotid glands than those in control plans.The mean doses to the partial submandibular glands were also significantly lower in treatment plans than in control plans.The PTV coverage was comparable between the two plans,as indicated by V_(100%),V_(95%),Dmin,CI,and HI.The doses to critical structures,including brainstem and spinal cord,were slightly but not significantly higher in treatment plans than in control plans.Conclusion A selective partial salivary gland-sparing approach reduces the doses to parotid and submandibular glands during IMRT,which may decrease the risk of post-radiation xerostomia while not compromising target dose coverage in patients with NPC.