Dose fusion and efficacy evaluation of different radical radiotherapy doses for cervical cancer.

BACKGROUND: The recommended external beam radiotherapy (EBRT) dose for cervical cancer is 40-50 Gy, but there is no consensus. In this study, 45-Gy and 50.4-Gy treatment groups were compared for fused doses to target tumor areas and organs at risk (OARs), clinical efficacy, and quality of life. METHODS: Seventy-nine cases receiving radical radiotherapy within the past 3 years were retrospectively analyzed. EBRT and three-dimensional brachytherapy dose fusion values were calculated for target areas and OARs using Elastix V5.0. Clinical efficacy was assessed using Response Evaluation Criteria in Solid Tumors (RECIST), adverse events using Common Terminology Criteria for Adverse Events v4.03 (CTCAE4.03), and quality of life using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30). RESULTS: Minimum fused dose delivered to 90% of the high-risk clinical target volume (HRCTV D90) did not differ significantly between 45-Gy and 50.4-Gy groups, whereas D2cc values of rectum and bladder (OARs) were significantly lower in the 45-Gy group (both p < 0.05). Further analysis showed that these D2cc differences resulted primarily from EBRT. No grade III-IV adverse events were observed in either group during follow up. Short-term clinical efficacy, adverse events, and EORTC QLQ-C30 functional and symptom scales also did not differ significantly between groups (all p > 0.05). However, quality of life was markedly higher in the 45-Gy group (p < 0.05). CONCLUSION: Appropriate EBRT dose reduction can reduce OAR irradiation without compromising total target area dose or clinical efficacy. Dose fusion can facilitate the judicious choice of EBRT to limit OAR exposure, reduce adverse events, and enhance the quality of life.

RefineNet-based automatic delineation of the clinical target volume and organs at risk for three-dimensional brachytherapy for cervical cancer.

BACKGROUND: In recent years, high-precision image-guided intensity-modulated radiation therapy combined with three-dimensional (3D) high-dose-rate (HDR) brachytherapy (BT) has become a recommended technique for radical radiotherapy for cervical cancer. This study first employed contrast-limited adaptive histogram equalization (CLAHE) for preprocessing of input data to achieve image enhancement. In this way, rapid and accurate automatic delineation of the clinical target volume (CTV) and organs at risk (OARs) in 3D BT for cervical cancer was achieved. METHODS: Two hundred cervical cancer patients who underwent radical radiotherapy from January 2016 to December 2018 were selected. After collecting the computed tomography (CT) image data of a patient, we constructed the radiotherapy CTV and OAR image libraries. A RefineNet-based deep learning protocol was used to segment the CTV and OARs for 3D BT for cervical cancer. In this study, a total of 1,000 rounds of training were carried out, and the model with the best performance was selected for subsequent iterative tuning. Finally, the clinical test was carried out, in which the CT images of 10 cases were tested one by one. The manual delineation results and the model output results for the CTV and OARs were compared to measure the performance of the model. RESULTS: Compared with the manually delineated CTV, the RefineNet model-based segmented CTV had a higher Dice similarity coefficient (DSC), Hausdorff distance (HD), and overlap index (OI), which were 0.861, 6.005, and 0.839, respectively. For OARs, the RefineNet-based model obtained the best results for bladder segmentation (DSC: 85.96%), respectively. The mean duration of RefineNet-based automatic contour processing of the CTV was 70 s, and the mean durations of RefineNet-based automatic delineation of the bladder, rectum, sigmoid colon, and small intestine were 67, 67.4, 63.8, and 60.8 s, respectively. The total time saved by RefineNet was approximately 60%. CONCLUSIONS: The RefineNet-based automatic delineation model for 3D BT for cervical cancer is a stable and highly consistent automatic delineation algorithmic model that has the potential to improve the consistency of target region delineation, simplify the radiotherapy procedure, and achieve rapid and accurate automatic delineation of CTVs and OARs.

Application of inverse planning simulated annealing in the treatment of cervical cancer with combined intracavitary and interstitial three-dimensional brachytherapy / 中华放射医学与防护杂志

Objective To evaluate the effect of an inverse planning simulated annealing (IPSA) in the treatment of cervical cancer with combined intracavitary and interstitial three-dimensional brachytherapy.Methods A total of 60 patients with locally advanced cervical cancer who received both external beam radiotherapy and combined intracavitary and interstitial brachytherapy in our hospital from October 2016 to July 2018 were enrolled.Patients were divided into four groups with 15 patients each according to the number of needles applied (1,2,3,and 4 needles,respectively).Dosimetric distributions were optimized with both Graphical optimization (GRO) and IPSA.Paired t-test was applied to compare the dosimetric differences between plans optimized with GRO and IPSA.Results The Dg0 and V100 of IPSA plans were higher than those of GRO (t=-4.742,-4.823,P＜0.05),while the conformity index (CI) and conformal index (COIN) were slightly lower than those of GRO plans (t=9.642,8.783,P＜0.05).No significant difference in the V150,V200,V300 between IPSA and GRO (P＞0.05) was observed.There was also no significant difference in the D2cm3 of bladder and rectum between IPSA and GRO (P＞0.05).The difference of Dg0 between IPSA and GRO was increased as the number of implanted needles increased,which increased from 4 cGy to 14 cGy as the number of needle increased from 1 to 4.The difference of V100 between GRO and IPSA was also increased as the number of needle increased.Conclusions In the treatment of cervical cancer with combined intracavitary and interstitial threedimensional brachytherapy,IPSA plan could improve the target coverage(D90,V100)without increasing the dose to the OARs and high dose region in the target compared with GRO.With the numbers of needles increased,the advantage of IPSA increased in terms of target coverage.

Efficacy and safety of the CT-guided three-dimensional brachytherapy combined with three-dimensional conformal radiotherapy in patients with locally middle- and late-stage cervical cancer / 肿瘤

Objective: This study aims to investigate the efficacy and safety of the CT-guided three-dimensional brachytherapy combined with three-dimensional conformal radiotherapy in patients with locally middle- and late-stage cervical cancer. Methods: Ninety-seven patients with stage II A-IV locally middle- and late- stage cervical squamous-cell carcinoma were treated with CT-guided three-dimensional brachytherapy combined with three-dimensional conformal radiotherapy. The short-term response was observed. The survival analysis was conducted by Kaplan-Meier method, and the univariate analysis of prognosis was performed by using log-rank test. The high-risk clinical target volume (HR-CTV) D90, D2cc of bladder, rectum and sigmoid colon and equivalent dose in 2 Gy per fraction (EQD2) were calculated. Results: The overall 2-year survival rate and 2-year progression-free survival rate of 97 patients were 93.8% and 92.1%, respectively. The differentiation degree and tumor size were significantly correlated with the overall survival (both P < 0.05). According to Radiation Therapy Oncology Group (RTOG) acute and late radiation reaction evaluation criterion, rates of grades 1 and 2 acute lower digestive adverse reaction were 15.5% (15/97) and 12.4% (12/97), respectively. The acute gastrointestinal adverse reaction grading was associated with HR-CTV D90 EQD2 (P = 0.027). The rate of grades 3 and 4 late digestive system adverse reactions was 1.0% (1/97). Conclusion: CT-guided three-dimensional brachytherapy combined with three-dimensional conformal radiotherapy in the treatment of locally middle- and late-stage cervical cancer has good efficacy, and the rate of late severe adverse reaction is low.

Application of ultrasound for simulated positioning of brachytherapy in cervical cancer: An alternative to traditional MRI/CT? / 中华放射肿瘤学杂志

The role of three-dimensional brachytherapy (3D-BT) in the radical treatment of cervical cancer has been widely recognized. Obtaining the image information through simulated positioning is a key step of 3D-BT.Currently, MRI/CT positioning has been commonly applied in clinical practice, which has respective limitations when applied in radiosurgery. Consequently, it is of necessity to explore an accurate, highly efficient and convenient positioning approach. Besides MRI and CT, ultrasound is a novel positioning method in clinical settings. Through literature review, the application of ultrasound in 3D-BT was summarized, aiming to provide reliable reference for clinicians.

A dosimetric study of 3D intracavitary brachytherapy in combination with applicator-guided IMRT boost for cervical cancer / 中华放射肿瘤学杂志

Objective To evaluate the dosimetric feasibility of three-dimensional(3D)intracavitary brachytherapy in combination with applicator-guided intensity-modulated radiation therapy(IMRT)boost for patients with locally advanced cervical cancer who have unfavorable topography following external beam irradiation. Methods A total of 7 patients with locally advanced cervical cancer who had unfavorable topography following external beam irradiation were included. Two plans were generated for brachytherapy using Oncentra 4.3 treatment planning system:3D intracavitary brachytherapy and 3D intracavitary brachytherapy in combination with applicator-guided IMRT boost.To further evaluate cumulative doses to organs at risk(OAR)in the four fractions of combined plans,two methods were used:simple dose-volume histograms(DVH)parameter addition and deformable image registration(DIR)-based DVH accumulation. The D90, V100, and conformity index(CI)were evaluated. The paired t-test or Wi1coxon signed rank test was used for statistical analysis. Results Compared with the 3D plan,the combined plan yielded higher D90, V100, and CI(P=0.000), but showed no significant difference in D2ccof the rectum,sigmoid colon,and bladder(P>0.05). There were also no significant differences in D2ccof the rectum, sigmoid colon, and bladder calculated by the two methods for calculating OAR cumulative doses, simple DVH parameter addition and DIR-based DVH accumulation(P>0.05). Conclusions For patients with cervical cancer who have unfavorable topography following external beam irradiation,3D intracavitary brachytherapy in combination with applicator-guided IMRT boost can improve target coverage and CI, without increasing OAR doses. DIR-based DVH accumulation and simple DVH parameter addition may be both acceptable for assessing OAR cumulative doses.

Dosimetric impacts of multichannel applicator in three-dimensional brachytherapy for advanced cervical carcinoma / 中华放射肿瘤学杂志

Objective To investigate the relationship between the channel design of tandem-andovoid (T&O) applicator and the doses to organs at risk (OARs) and target volume in three-dimensional brachytherapy for advanced cervical carcinoma.Methods The data on 15 patients with advanced cervical carcinoma treated with three-dimensional brachytherapy in our hospital from 2015 to 2016 were collected,and 30 randomly selected high-dose-rate titanium T&O plans were retrospectively studied.CT-guided,conformal brachytherapy plans were generated.To simulate T&O applicator,the tandem applicator was virtually compared with the T&O plans with the target volume and OARs remaining unchanged.The DVH parameters of the rectum,bladder,and sigmoid were compared using the paired t test.Results For T&O plans and tandem applicator plans,the mean D2cc of the rectum was 387.8±96.8 cGy and 340.8±88.1 cGy,respectively;the mean D2cc of the bladder was 443.2± 87.5 cGy and 719.4± 243.0 cGy,respectively;the mean D2cc of the sigmoid was 330.3±88.8 cGy and 383.1±105.6 cGy,respectively.In the T&O plans,the doses to the rectum,bladder,and sigmoid were within the limits (rectum:D2cc ≤ 500 cGy;bladder:D2cc ≤ 550 cGy;sigmoid:D2c ≤ 500 cGy),while D2cc of the bladder and sigmoid was higher or partially higher than the limits.T&O plans showed a significant reduction in bladder D2cc and sigmoid D2cc compared with the tandem applicator plans (all P＜0.05).Conclusions Compared with tandem applicator plans,plans using T&O applicator provide significant sparing of bladder and sigmoid tissues in three-dimensional brachytherapy for cervical carcinoma,but the toxicities require further investigation.

Dosimetric study of three-dimensional image-quided brachytherapy combined with intracavitary/ interstitial brachytherapy in locally advanced cervical cancer / 中华放射肿瘤学杂志

Objective To explore the dosimetric advantages of computed tomography-based and ultrasound-guided three-dimensional image-quided brachytherapy (3D-IGBT) combined with intracavitary/interstitial (IC/IS) brachytherapy for locally advanced cervical cancer.Methods A total of 45 patients with FIGO (2009) stage ⅠB2-ⅣA locally advanced cervical cancer who received radical external beam radiotherapy and 3D-IGBT combined with IC/IS brachytherapy in our hospital from 2013 to 2014 were analyzed.After the treatment with 192Ir-based IC/IS brachytherapy,patients had needles removed from the original images and received treatment only from IC radiation sources.Dosimetric differences in the planning D90 for high-risk clinical target volume (HR-CTV),D90 for intermediate-risk CTV (IR-CTV),and D2 cm3 for the bladder,rectum,sigmoid colon,and small intestines were determined and analyzed by paired t-test.Results A total of 260 after-loading treatment plans,including IC/IS treatment plans for 130 patients and IC treatment plans for 130 patients,were made.The D90 for HR-CTV and D90 for IR-CTV in the IC/IS brachytherapy group were significantly higher than those in the IC brachytherapy group (P =0.000;P =0.000).Moreover,the average D2cm3 values for the bladder and rectum were significantly reduced in the IC/IS brachytherapy group compared with those in the IC brachytherapy group (P =0.000;P =0.006).Conclusions The 3D-IGBT combined with IC/IS brachytherapy not only achieves a higher dose for the target volume,but also reduces the radiation dose to the bladder and rectum in the treatment of locally advanced cervical cancer.

Impact of dosimetric parameters on local control for patients treated with three-dimensional pulsed dose-rate brachytherapy for cervical cancer.

PURPOSE: To investigate the impact of dose-volume histograms parameters on local control of three-dimensional (3D) image-based pulsed dose-rate brachytherapy (BT). METHODS AND MATERIALS: Within a French multicentric prospective study, the data of the 110 patients treated for cervical cancer with external beam radiotherapy followed by 3D image-based and optimized pulsed dose-rate BT were analyzed. Delineation procedures were performed on magnetic resonance imaging in a minority of cases and on CT for the majority of cases, adapted from the Gynaecological Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology recommendations. Optimization procedure was left to the discretion of the treating center. RESULTS: At 2 years, local control rate reached 78%. Dose to Point A, total reference air kerma, and intermediate-risk clinical target volume (IR-CTV) V60 were predictive factors for local control (p = 0.001, p = 0.001, and p = 0.013, respectively). Patients with IR-CTV V60 <75% had a relative risk of local recurrence of 3.8 (95% confidence interval, 1.4-11.1). There was no correlation found between the high-risk clinical target volume dosimetric parameters and local control. CONCLUSIONS: This multicentric study has shown that 3D image-based BT provides a high local control rate for cervical cancer patients. The V60 for IR-CTV was identified as an important predictive factor for local control.