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Objective:To explore the influence of body mass index (BMI) changes on the doses to normal tissues and adverse reactions of the lower digestive system and urinary system in the brachytherapy for cervical cancer.Methods:Clinical data of 80 cervical cancer patients who received radical radiotherapy in our hospital from January 2020 to February 2021 were retrospectively analyzed. All patients received external beam radiation ± chemotherapy + brachytherapy. The delineation method of target areas and organs at risk (OAR) was determined based on the recommended scheme of GEC-ESTRO. The target areas included high risk (HR)-CTV and intermediate risk (IR)-CTV, and OAR consisted of rectum, sigmoid colon, bladder, and small intestine. The target area dose was evaluated by D 90% of the HR-CTV. The OAR volume dose was evaluated by using D2cm3. Correlation analysis was used to compare the dosimetric relationship between BMI and D2cm3, D1cm3 and D0.1cm3 in bladder, rectum, colon and small intestine. Logistic regression analysis was adopted to analyze the risk factors of acute and late adverse reactions in the lower gastrointestinal system and urinary system. Whether BMI was a risk factor was validated. Results:BMI was negatively correlated with the D2cm3, D1cm3 and D0.1cm3 of the small intestine ( P=0.034, 0.024, 0.034), and the correlation coefficients were -0.240, -0.255, and -0.241, respectively. Logistic regression analysis showed that BMI was not a risk factor for the occurrence of acute and late adverse reactions in the lower gastrointestinal system and urinary system. For every 1 Gy increase of D2cm3, D1cm3 and D0.1cm3 in the small intestine, the relative risk of acute adverse reactions in the lower gastrointestinal system was increased by 16.6%, 15.1%,and 12.7%, respectively. Conclusions:In brachytherapy for cervical cancer, there is a negative correlation between BMI and D2cm3, D1cm3 and D0.1cm3 of the small intestine. As the BMI of patients declines, the radiation dose to the small intestine shows an increasing trend, which may increase the risk of acute adverse reactions in the lower gastrointestinal system.
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Objective To explore the prognostic factors for the recurrence of vaginal stump of earlystage cervical cancer after radical hysterectomy and evaluate the effect on clinical prognosis.Methods Clinical data of stage Ⅰ-ⅡA cervical cancer patients undergoing radical hysterectomy in Guizhou Cancer Hospital from January,2007 to December,2016 were retrospectively analyzed.Results A total of 493 patients were enrolled and followed up until May 30,2018.Among them,96.6％(474/493) completed the follow-up.The median age was 45 years.Patients aged 40-50 years had a high incidence rate.In total,451 cases (91.48％) had no recurrence of vaginal stump.The average time without stump recurrence was 51.2 months and the median time without stump recurrence was 44.8 months.Multivariate Cox regression analysis demonstrated that pelvic external irradiation and brachytherapy were the independent prognostic factors for the recurrence of vaginal stump (P=0.000,0.000).Tumor size,lymph node metastasis and pelvic external irradiation were the independent prognostic factors for overall survival (P=0.045,0.022,0.000).Conclusions Pelvic external irradiation and brachytherapy play an extremely pivotal role in reducing the risk of vaginal stump recurrence after radical hysterectomy for patients with stage Ⅰ-Ⅱ A cervical cancer.Tumor size,lymph node metastasis and pelvic external irradiation are the independent prognostic factors for overall survival of patients with stage Ⅰ-Ⅱ A cervical cancer following radical hysterectomy.
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Objective To investigate the effect of different uterine positions upon the dose distribution and target area conformability of organ at risk ( OAR) and explore the population suitable for 2-dimensional brachytherapy by comparing the dosimetry between CT-guided 3-and 2-dimensional brachytherapy for cervical cancer. Methods Thirty patients with cervical cancer received 72 cycles of 3-dimensional brachytherapy and then 2-dimensional brachytherapy was designed. The deviation angle of the uterus from the longitudinal asix on the coronal and sagittal CT images was measured. The obtained data were divided into the A to D and the group Ⅰ to Ⅳ according to the deviation angle ( T) of uterus position from the longitudinal axis on the sagittal CT images and the volume of HRCTV ( VHRCTV) to identify the optimal uterine position and range of VHRCTV for 2-dimensional brachytherapy. Statistical analysis was performed by paired t-test. Results The deviation angle of uterine position was not significantly correlated with the target CI index or D90 of HRCTV in both brachytherapy plans ( P value between 0. 077-0. 633 ) , whereas it was positively correlated with the D2 cm3 of bladder ( P value between 0. 001-0. 030) and negatively associated with the D2 cm3 of rectum in both 2-and 3-dimensional brachytherapy (P value between 0. 011-0. 016).In group B (|T|≤10°) and group Ⅲ(VHRCTVvalue between 86-96 cm3),the OAR parameters and CI index did not significantly differ between two brachytherapy plans ( P value between 0. 040-0. 463 ) , whereas varying degree of statistical differences was observed among other groups (P value between 0. 000-0. 940). Conclusions Although uterine position exerts no effect upon the conformal index of target area, it can affect the dose distribution of OAR. No statistical significance is noted in the dosimetry between 3-and 2-dimensional brachytherapy plans when the uterine position is almost flat (|T|≤10° ) and the radiotherapy target area is appropriate ( VHRCTVvalue between 86-96 cm3 ) . In this situation, 2-dimensional brachytherapy is the optimal option.
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Objective To discuss the dosimetric advantage of computed tomography-guided interstitial brachytherapy compared with the conventional intracavitary brachytherapy for locally advanced cervical cancer,offering a more advantageous clinical treatment approach. Methods Twenty-eight locally advanced cervical cancer patients with bulky tumors ( tumor size>5 cm) after external beam radiotherapy received computed tomography-guided interstitial brachytherapy. Dosimetric outcomes of the current study, including the total dose ( external beam radiotherapy+ brachytherapy ) D90 for the HR-CTV and D2cc for the bladder,rectum, and sigmoid, were compared with a former patient group consisting of 30 patients who received the conventional intracavitary brachytherapy ( uterine tandem+ ovoid pairs ) . Results The mean D90 value for HR-CTV in the intracavitary brachytherapy group and interstitial brachytherapy group were (76.9±5. 7) and ( 88.1± 3. 3) Gy, respectively. The D2cc for the bladder, rectum, and sigmoid in the intracavitary brachytherapy group and interstitial brachytherapy group were (84.7±6. 8) Gy,(69.2±4. 2) Gy,(67.8±4. 5) Gy and (81.8±6. 5) Gy,(6.8±4. 0) Gy,(64.8±4. 1) Gy,respectively.1-year local tumor control rate in the intracavitary brachytherapy group and interstitial brachytherapy group were 59. 3％ and 85. 2％, respectively. Conclusions CT-guided interstitial brachytherapy shows a significant dosimetric advantage compared with the conventional intracavitary brachytherapy, and is, thereby, clinically possible feasible. However,the long term curative effect and toxicity need to be further investigated.
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Objective To compare the dosimetric parameters between the use of Tandem and Ring (TR;Nucletron#090.617) or Tandem and Ovoid (TO;Nucletron#189.730) applicators during three-dimensional (3D) high-dose rate (HDR) brachytherapy (BT) for cervical cancer.Methods The records of 40 cervical cancer (ⅡB-ⅣA) patients treated with 3D-image-guided HDR-BT were reviewed.Of these 40 patients, 20 were treated with the TO applicator, and 20 with the TR applicator.The D100% and V150% of the clinical target volume (CTV) and the D2 cc of organs at risk (OAR)(the rectum, bladder, and small intestine) during 3D-HDR-BT using TO and TR were compared using the independent sample t-test.ResultsOverall metrics:CTV volume:66.04±13.86 cm3(TR) vs.65.67±15.08 cm3(TO)(P=0.052);CTV D100:3.71±0.34 Gy (TR) vs.3.37±0.49 Gy (TO)(P=0.016);CTV V150%:0.54±0.02(TR) vs.0.56±0.04(TO)(P=0.034);rectum D2 cc:3.38±0.30 Gy (TR) vs.2.95±0.80 Gy (TO)P=0.037);bladder D2 cc:4.33±0.39 Gy (TR) vs.2.93±1.27 Gy (TO)(P=0.00);and small ntestine D2 cc:3.04±1.02 Gy (TR) vs.3.41±0.57 Gy (TO)(P=0.171).Conclusions TR has better CTV coverage than TO during 3D HDR brachytherapy for cervical cancer.In addition, D2 cc of the rectum and bladder were both igher with TR than with TO, though there is no significant dosimetric difference in the small intestine between the two applicators.Therefore, tumor location, extent of invasion, and vaginal conditions should be considered when selecting the suitable pplicator for the treatment of cervical cancer.
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Cervical cancer is one of the leading causes of death in women with malignancies worldwide.Brachytherapy plays an essential role in the radiation therapy for cervical cancer, and its combination with external beam radiation is indicated for previously untreated or recurrent cervical cancer at various stages without distant metastasis.Magnetic resonance imaging (MRI) has superior resolution of soft tissue, which allows for accurate delineation of target volume, protects organs at risk (OARs), and thus improves treatment outcomes.In recent years, many studies have demonstrated the feasibility and superiority of three-dimensional MRI-guided brachytherapy for cervical cancer.This article aims to elaborate on relevant MRI techniques, selection of applicators, delineation of target volume and OARs, evaluation of treatment plans, and the clinical effect of three-dimensional MRI-guided brachytherapy.
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Objective To examine the interfractional dosimetric variations among inverse three-dimensional (3D) plan, forward 3D plan, and two-dimensional (2D) plan of intracavitary brachytherapy for cervical cancer, and to discuss the risk of implementing the interval plan on different implantation applicators at short time intervals.Methods Twenty-five groups of CT-guided intracavitary brachytherapy (two consecutive radiations at ≤4 d apart) plans from 11 cervical cancer patients who received radical radiation therapy in our hospital were reviewed and compared.The dwelling location and time of the first intracavitary brachytherapy plan (Plan-1) were simulated on the CT image of the second intracavitary brachytherapy to form Plan-1-S.The target coverage indices and D 2 cc of organs at risk (OARs) of Plan-1-S and Plan 2(actual plan of the second intracavitary brachytherapy) under the three planning modes were recorded and compared using the paired t-test, Wilcoxon signed rank test, and ANOVA.Results The D90, D100, and V100 of high-risk CTV were significantly lower in Plan-1-S created under the inverse mode in the actual plan (-9.11±13.46%,-13.16±18.79%, and-7.80±13.34%, P=0.002, 0.002, and 0.005, respectively).D90, D100, and V100 of the interval plan had the greatest reduction under the inverse mode (76%, 80%, and 76%, respectively).The maximum reductions in D90, D100, and V100 were 332.14 cGy (2D), 244.12 cGy (forward), and 41.76%(inverse).OAR overdose occurred most frequently under the forward mode;the rates of D90, D100, and V100 reductions accompanied by one OAR overdose were 29.41%, 37.50%, and 25.00%, and the rates of D90, D100, and V100 reductions by two OAR overdoses were 5.88%, 12.50%, and 6.25%,respectively.Overdose occurred most frequently in the small intestine (36%).Comparison of the three planning modes showed that the inverse plan had a greater reduction in each target coverage index than the 2D plan.Conclusions The simulated interval plan can significantly reduce target coverage and increase the risk of OAR overdose regardless of the planning mode and the short time intervals, and is therefore not recommended for clinical application.
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Objective To investigate the clinical application of Utrecht applicator in three-dimensional image-guided brachytherapy (3D-IGBT) for locally advanced cervical cancer,as well as its application discipline in intracavitary/interstitial (IC/IS) therapy.Methods A retrospective analysis was performed for the clinical data of 45 patients with locally advanced cervical cancer who received radical radiotherapy,and the patients received external beam radiotherapy followed by 3D-IGBT.A total of 130 times (n =45) of IC/IS therapy were performed,and the patients who received such therapy were all enrolled.The patients who met the target dose fractionation defined in the plan were enrolled as group A (n=37,86 times),and the other patients were enrolled as group B (n=22,44 times).Two groups difference was analyzed with Group t-test.Results The frequencies of use of 15-,20-,and 25-mm ovoids by the applicator were 50.0％,20.0％,and 30.0％,respectively,and the 30-mm ovoid was not used.A total of 499 needles were used,and the frequencies of use of 6,7,10,and 11 insertion holes were 23.1％,21.2％,21.2％,and 24.1 ％,respectively.Group A had a significantly lower mean number of the needles than group B (3.7 vs.4.2,P=0.008).Compared with group B,group A had a significantly lower mean high-risk clinical target volume (CTV)(40.71±18.43 cm3 vs.51.81±14.74 cm3,P=0.001),as well significantly lower width and height of high-risk CTV (P=0.011 and 0.006),but the thickness of high-risk CTV was similar between the two groups (P=0.595).The difference between height and insertion depth (DH) was similar between the two groups (P=0.366).Group A had a smaller difference between width and pinhole distance Dw than group B (P=0.007).Conclusions When IC/IS therapy is performed for locally advanced cervical cancer,the 15-,20-,and 25-mm ovoids of Utrecht applicator and 6,7,10,and 11 insertion holes are frequently used.When the number of needles is no less than 4 and the depth is no less than 3 cm,width is the major factor which affects the planned dose.
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Objective To analyze the setup errors of external?beam and intracavitary radiotherapy for cervical cancer based on the data of cone?beam computed tomography ( CBCT) , and to provide a basis for clinical practice. Methods Sixty patients with stage ⅡA?ⅢB cervical cancer who were admitted to our hospital and underwent external?beam and intracavitary radiotherapy from March to June, 2015 were enrolled as subjects. Sixty patients with stage ⅡA?ⅢB cervical cancer undergoing conventional external?beam radiotherapy within the same period were also enrolled. The CBCT?based setup errors, containing setup errors in x, y, and z directions and three?dimensional vector deviation, in the initial treatment were obtained from each patient. Comparison of errors between the two treatment approaches was made by independent?samples t test. Results Fitting the data to a linear model revealed that the setup errors in x, y, and z directions increased with the increase in the distance between the position reference point and the center point of the target volume. External?beam radiation combined with intracavitary radiation had significantly reduced setup errors in x, y, and z directions than the conventional external?beam radiation ( 0.13± 0?12 vs. 0.31± 0?24, P=0?000;0.23±0?18 vs. 0.47±0?36, P=0?001;0.18±0?11 vs. 0.27±0?18, P=0?001). Conclusions In order to reduce the setup errors, CT scan needs not only a reference marker as close as possible to the center of the tumor, but also a reliable and accurate approach for postural fixation.
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Objective To investigate the dosimetric differences between Utrecht applicator and ring applicator in three-dimensional (3D) conformal brachytherapy for locally advanced cervical cancer.Methods Twenty-five patients with locally advanced cervical cancer were treated with magnetic resonance imaging-guided 3D conformal brachytherapy.Utrecht applicator and ring applicator were used interchangeably for 96 cycles.Patients were divided into two groups according to the type of applicator.Each group received 48 cycles of treatment, in which ring applicator was first applied for 26 cycles and Utrecht applicator was first applied for 22 cycles.High-risk clinical target volume ( HR-CTV) , width, thickness, and D90 at the point A level, D2 cm3 of organs at risk (OARs), V7 Gy , W7 Gy,A, V7 Gy ,A, and W/T7 Gy were evaluated and analyzed using paired t-test.Results There were no significant differences in HR-CTV and the width, thickness, and D90 at the point A level between the Utrecht group and the ring group ( P=0.487;P=0.340;P=0.857;P=0.921);there were no significant differences in D2 cm3 values of bladder, rectum, sigmoid, and bowel between the two groups ( P=0.136;P=0.802;P=0.985;P=0.458);there were no significant differences in V7 Gy and T7 Gy,A between the two groups ( P=0.076;P=0.435) .The Utrecht group had a significantly larger W/T7 Gy,A than the ring group ( P=0.002 ) .Conclusions Utrecht applicator is appropriate for patients with relatively large width and width/thickness ratio of HR-CTV at the point A level.
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Objective To explore the correlation between the dose measured in the rectum and reference dose in three?dimensional brachytherapy ( 3DBT ) for cervical cancer, and to evaluate the significance of the dose measured in the rectum. Methods Fifty patients receiving radiotherapy for cervical cancer were selected, and 3DBT was performed after pelvic external beam radiotherapy. According to the rectal monitoring method recommended in the report ICRU38, in vivo monitoring was applied to obtain the dose measured in the rectum, reference point dose ( DICRU ) , and D2 cm3 , and the planned dose was obtained from the planning system. The differences in these values were determined by the paired t?test and correlation analysis was performed with Pearson test. Results The dose measured in the rectum was higher than the planned dose (3. 48 vs. 3. 25,P=0. 000), and lower than DICRU(3. 48 vs. 3. 71,P=0. 000) and D2 cm3(3. 48 vs. 3. 87,P=0. 002). A linear relationship existed between the dose measured in the rectum and the planned dose, with a deviation percentage of-20% to 40% and an average deviation of 8. 16%;63%of the patients with cervical cancer had a deviation of<± 10%;the maximum deviation was 60%. The dose measured in the rectum had a strong correlation with DICRU(r=0. 722), but a weak correlation with D2 cm3 ( r=0. 284) . Conclusions During 3DBT for cervical cancer, the dose measured in the rectum has certain deviations, but has a linear correlation with the planned dose. Both the dose measured and the planned dose underestimate the dose at the reference point in the rectum, and in vivo rectal monitoring may be an effective method for quality control.
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Objective To investigate the relationship between dose-volume histogram (DVH) parameters and the late side effects (LSE) of the rectum in external-beam radiotherapy combined with computed tomography (CT)-based brachytherapy for locally advanced cervical cancer.Methods From 2008 to 2011,18 patients with stage ⅡB-ⅢB cervical cancer received external-beam radiotherapy and CTbased brachytherapy.The DVH parameters of high-risk clinical target volume (HR CTV) D90,point A dose,and D1 cm3 and D2 cm3 of the rectum and bladder were calculated by Oncentra HDR treatment planning system.Survival outcomes were followed up and rectal LSE were evaluated by RTOG/EORTC grades.Results The point A dose and HR CTV D90 were (93.0 ± 5.5) Gy and (73.6 ± 11.9) Gy,respectively.The median follow-up was 26 months.No recurrence was found during follow-up.Eight patients had mild and moderate rectal LSE,and their rectum D2 cm3 and D1 cm3 were significantly higher than those of patients without mild and moderate rectal LSE (D2 cm3:(87.4 ± 3.8) Gy vs.(75.8 ± 7.4) Gy,P =0.004 ; D1 cm3:(96.4±6.6) Gy vs.(80.5± 7.1) Gy,P=0.001).Conclusions HR CTV D90 in CT-based brachytherapy for locally advanced cervical cancer might be lower than that in the MRI-based plan.Rectum D2 cm3 is recommended to be less than 75 Gy.
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Objective To evaluate the clinical value of different radiotherapy protocols in the treatment of advanced cervical cancer. Methods From 1976 to 2006,763 patients with stage Ⅲ cervical cancer(722 with squamous cell carcinoma and 41 with adenocarcinoma)were treated by radiotherapy in our hospital. 113 patients were treated by two-field whole pelvic irradiation in conventional fractionation plus brachytherapy (CF group), 44 by four-field whole pelvic irradiation in accelerated hyperfractionation plus brachytherapy( AHF group), and 606 by concomitant four-field unconventional fractionation radiotherapy and brachytherapy(FRT group). Sixty-one patients were treated by radiotherapy and chemotherapy. Among 350 patients who had complete data, the short-term efficacy and toxicities were compared. Results For patients in CF,AHF and FRT groups, the 3-year overall survival rates (OS) were 65.7%, 66.8% and 44.3%, respectively (P=0.000), and the 5-year OS were 65.7 % ,66.8 % and 36.3 %, respectively (P=0.000). The 10-year OS were 43.3% and 31.9% in CF and FRT groups(P=0.200). For squamous cell carcinoma,the OS was higher of patients with chemotherapy than those without. In 350 patients who had complete data,the local control rates of CF, AHF and FRT groups were 83.0% ,93.2% and 86.1%, respectively(X2=2.70, P=0.259);AHF group had the lowest side effect rate, especially skin reaction (9.1%,X2=20.25,P=0.002) ;CF group had the lowest acute bone marrow suppression rate(X2=25.95,P=0.000);for squamous cell carcinoma, the OS was higher in patients with chemotherapy than those without;the acute bone marrow and intestinal toxicities were more in patients with chemotherapy than those without. Conclusions CF and AHF groups have similar 5-year OS of patients with advanced cervical cancer. AHF group has less toxicities, shorter treatment course and a trend of better local control. Concurrent chemoradiation could improve survival and local control of the patients with advanced squamous cell cervical cancer while increase the side effects. The individual condition should be considered to choose the treatment protocol.