Beam Radiotherapy For Cervical Cancer Research Articles

The Current use of Adaptive Strategies for External Beam Radiotherapy in Cervical Cancer: A Systematic Review

AimsVariability in the target and organs at risk (OARs) in cervical cancer treatment presents challenges for precise radiotherapy. Adaptive radiotherapy (ART) offers the potential to enhance treatment precision and outcomes. However, the increased workload and a lack of consensus on the most suitable ART approach hinder its clinical adoption. This systematic review aims to assess the current use of adaptive strategies for cervical cancer and define the optimal approach. Materials and methodsA systematic review of current literature published between January 2012 and May 2023 was conducted. Searches used PubMed/Medline, Cochrane Library, and Web of Science databases, supplemented with the University of Manchester, Google Scholar, and papers retrieved from reference lists. The review assessed workflows, compared dosimetric benefits, and examined resources for each identified strategy. Excluded were abstracts, conference abstracts, reviews, articles unrelated to ART management, proton therapy, brachytherapy, or qualitative studies. A narrative synthesis involved data tabulation, summarizing selected studies detailing workflow for cervical cancer and dosimetric outcomes for targets and OARs. ResultsSixteen articles met the inclusion criteria; these were mostly retrospective simulation planning studies, except four studies that had been clinically implemented. We identified five approaches for ART radiotherapy for cervical cancer: reactive and scheduled adaptation, internal target volume (ITV)-based approach using library of plans (LOP), fixed-margin approach using LOP, and real-time adaptation, with each approach reducing irradiated volumes without compromising target coverage compared to the non-ART approach. The LOP-based ITV approach is the most used and clinically assessed. ConclusionIdentifying the optimal strategy is challenging due to dosimetric assessment limitations. Implementing cervical cancer ART necessitates strategic optimization of clinical benefits and resources through research, including studies to identify the optimal frequency, and prospective evaluations of toxicity.

846: Adaptive strategies for external beam radiotherapy in cervical cancer: a systematic review.

846: Adaptive strategies for external beam radiotherapy in cervical cancer: a systematic review.

Assessment of Changes of Bladder Volume and Rectal Volume Using 4DCT Scan During External Beam Radiotherapy for Cervical Cancer- Observation Study

Assessment of Changes of Bladder Volume and Rectal Volume Using 4DCT Scan During External Beam Radiotherapy for Cervical Cancer- Observation Study

Dosimetric Evaluation of the Benefits of Intensity Modulated Techniques in Cervical Cancer Radiotherapy

"External beam radiotherapy for cervical cancer using 3D conformal radiotherapy (3D-CRT) is a standard procedure in Romania. A dosimetric planning comparison between 3D-CRT and intensity modulated techniques evaluating both target parameters and organs at risk could justify the implementation of the latter techniques in clinical settings. 50 cervical cancer patients were treated with 3D-CRT, and equivalent plans simulated with IMRT and VMAT for a comparative dosimetric assessment. In addition to providing better compliance and homogeneity, intensity modulated techniques provide superior protection for organs at risk, especially for bowel bag, influencing patients’ quality of life. "

CBCT-based deformable dose accumulation of external beam radiotherapy in cervical cancer

Background: Delivered radiotherapy doses do not exactly match those planned for a course of treatment, largely due to inter-fraction changes in anatomy. In this study, accumulated delivered dose was calculated for a sample of cervical cancer patients, by deformably registering daily cone beam computed tomography (CBCT) images to the planning computed tomography (CT) scan. Planned and accumulated doses were compared for the clinical target volume (CTV), bladder, and rectum. Material and Methods: For 10 patients receiving 45 Gy in 25 fractions of external beam radiotherapy, daily dose distributions were calculated on CBCT. These images were deformed onto the planning CT and the dose was accumulated using Velocity 4.1 (Varian Medical Systems, Palo Alto, USA). The quality of deformable image registration was evaluated visually and by calculating Dice similarity coefficients and mean distance to agreement. Results: V95%>99% was achieved for the primary CTV in 9/10 patients for the planned dose distribution and 7/10 patients for the accumulated dose distribution. Primary CTV coverage by 95% of the prescription dose was reduced in one patient, due to an increase in anterior-posterior separation. Comparison of planned and accumulated dose volume histograms (DVHs) for the bladder and rectum found agreement within 5% at low and intermediate doses, but differences exceeded 20% at higher doses. Direct addition of CBCT DVHs was seen to be a poor estimate for the accumulated DVH at higher doses. Conclusion: Computation of delivered radiotherapy dose that accounts for inter-fraction anatomical changes is important for establishing dose-effect relationships. Updating delivered dose distributions after each fraction would support informed clinical decision making on any potential treatment interventions.

PO46 Presentation Time: 4:45 PM: MRI-Guided Adaptive External Beam Radiotherapy for Cervical Cancer

Cervical cancer is the fourth most common cancer in women worldwide. Traditionally, bulky cervical tumors or those with clinical nodal involvement are treated with definitive chemoradiation therapy. Pelvic or extended field radiation has traditionally been delivered using 3-dimensional conformal radiotherapy with fields that are not altered during treatment. However, there is an emerging role for intensity modulated radiotherapy as well as adaptive planning. Although MRI-based linear accelerators have recently been used for image guidance during brachytherapy, to our knowledge, there are no reports of adaptive planning for cervical cancer cases using MRI-based linear accelerators. We present a case of a postpartum patient with a bulky cervical adenocarcinoma who underwent replanning twice during treatment due to uterine and tumor shrinkage. The use of a MRI-based linear accelerator facilitated both replanning and tumor assessment.

Results of computer tomography-based adaptive brachytherapy in combination with whole-pelvic- and central-shielding-external beam radiotherapy for cervical cancer

To evaluate treatment results and investigate predictors of local control. In this retrospective study of 236 patients with cervical cancer, we administered CT-based adaptive brachytherapy (BT) in combination with whole- pelvic (WP)- and central shielding (CS)- external beam radiotherapy (EBRT) with or without chemotherapy. The study cohort comprised patients with cervical cancer treated with definitive radiotherapy (RT) or concurrent chemoradiotherapy between June 2013 and March 2019. Local control (LC), overall survival (OS), and late toxicity were evaluated. Predictive factors for LC were analyzed by univariate and multivariate analyses. Median doses of WP- and CS-EBRT and BT were 30.6 GyEQD2, 19.8 GyEQD2, and 40.3 GyEQD2, respectively. The 3-year LC rates for T1b2, T2a, T2b, T3b, and T4 were 100%, 100%, 97.3%, 86.9%, and 91.7%, respectively (p = 0.346). The 3-year OS for Stages IB, IIB, IIIB, IIIC, and IVA were 100%, 94.8%, 82.5%, 81.7%, and 74.6%, respectively (p = 0.037). Rates of Grade 3-4 gastrointestinal and genitourinary toxicities were 3.8% and 1.7%, respectively. Multivariate analysis showed that T3-4, nonsquamous cell histology, and high-risk clinical target volume (CTVHR) D90 of BT < 36GyEQD2 were independently associated with significantly poorer LC. The combination of WP- and CS-EBRT and CT-based IGBT with or without concurrent chemotherapy produced favorable LC outcomes with low rates of late toxicities for patients with small or medium-sized tumors. However, LC was less favorable for patients who had large T3 disease, and the use of CS requires caution in these patients.

Clinical acceptability of fully automated external beam radiotherapy for cervical cancer with three different beam delivery techniques.

PurposeTo fully automate CT‐based cervical cancer radiotherapy by automating contouring and planning for three different treatment techniques.MethodsWe automated three different radiotherapy planning techniques for locally advanced cervical cancer: 2D 4‐field‐box (4‐field‐box), 3D conformal radiotherapy (3D‐CRT), and volumetric modulated arc therapy (VMAT). These auto‐planning algorithms were combined with a previously developed auto‐contouring system. To improve the quality of the 4‐field‐box and 3D‐CRT plans, we used an in‐house, field‐in‐field (FIF) automation program. Thirty‐five plans were generated for each technique on CT scans from multiple institutions and evaluated by five experienced radiation oncologists from three different countries. Every plan was reviewed by two of the five radiation oncologists and scored using a 5‐point Likert scale.ResultsOverall, 87%, 99%, and 94% of the automatically generated plans were found to be clinically acceptable without modification for the 4‐field‐box, 3D‐CRT, and VMAT plans, respectively. Some customizations of the FIF configuration were necessary on the basis of radiation oncologist preference. Additionally, in some cases, it was necessary to renormalize the plan after it was generated to satisfy radiation oncologist preference.ConclusionApproximately, 90% of the automatically generated plans were clinically acceptable for all three planning techniques. This fully automated planning system has been implemented into the radiation planning assistant for further testing in resource‐constrained radiotherapy departments in low‐ and middle‐income countries.

Role of vaginal brachytherapy boost following adjuvant external beam radiotherapy in cervical cancer: Turkish Society for Radiation Oncology Gynecologic Group Study (TROD 04-002)

ObjectiveThere are a limited number of studies supporting vaginal brachytherapy boost to external beam radiotherapy in the adjuvant treatment of cervical cancer. The aim of this study was to assess...

Is Intrafraction Motion an Important Consideration in MR Guided External Beam Radiotherapy for Cervical Cancer?

Is Intrafraction Motion an Important Consideration in MR Guided External Beam Radiotherapy for Cervical Cancer?

Cone beam computed tomography-based monitoring and management of target and organ motion during external beam radiotherapy in cervical cancer.

Background and purposeOrgan motion is a challenge during high-precision external beam radiotherapy in cervical cancer, and improved strategies for treatment adaptation and monitoring of target dose coverage are needed. This study evaluates a cone beam computed tomography (CBCT)-based approach.Materials and methodsIn twenty-three patients, individualized internal target volumes (ITVs) were generated from pre-treatment MRI and CT scans with full and empty bladders. The target volumes encompassed high-risk clinical target volume (CTV-T HR) (gross tumor volume + remaining cervix) and low risk (LR) CTV-T (CTV-T HR + uterus + parametriae + upper vagina). Volumetric Modulated Arc Therapy (VMAT) was used to deliver a dose of 45 Gy in 25 fractions. CBCTs were used for setup and for radiation therapists (RTTs) to evaluate the target coverage (inside/outside the planning target volume). CBCTs were reviewed offline. Estimates of the dose delivered with minimum (point) doses across all fractions to CTV-T HR (aim 42.75 Gy) and CTV-T LR (aim 40 Gy) were assessed. In patients with insufficient dose coverage, re-plans were generated based on previous imaging.ResultsMedian (range) of the ITV-margins (mean of anterior-posterior margins) related to uterus and cervix was 1.2 (0.5–2.2 and 1.0–2.1) cm. RTTs were able to assess the target coverage in 90% of all CBCTs (505/563). With re-planning, one patient had considerable benefit (12.7 Gy increase of minimum dose) to CTV-T LR_vagina, four patients had improved dose to the CTV-T LR_uterus (1.2–1.8 Gy), and 3 patients did not benefit from re-planning.ConclusionsDaily CBCT-based monitoring of target coverage by the RTTs has proven safe with limited workload. It allows for reduction in the treated volumes without compromising the target dose coverage.

Effect of image guidance on doses to the rectum and bladder in radiotherapy for cervical cancer

Objective To analyze the effect of image guidance on the doses to the rectum and bladder in radical external beam radiotherapy for cervical cancer, and to investigate the reasonable application mode of image-guided radiotherapy (IGRT) in the treatment of cervical cancer. Methods A total of 20 patients with cervical cancer who underwent helical tomotherapy (HT) in PLA Army General Hospital from 2012 to 2016 were enrolled in this study. A megavoltage computed tomography (MVCT) scan was performed before each treatment. The obtained MVCT images were used for dose reconstruction in the adaptive module of HT to obtain the actual dose (Plan-1) and the non-image-guided dose was simulated (Plan-2). Each single dose distribution and the corresponding fused CT image were sent to the software MIM 6.0 to obtain the total radiation dose by dose superposition. The radiation doses and volumes of the rectum and bladder were compared between the two therapeutic plans. Results The radiation doses to the rectum and bladder in Plan-2 were significantly higher than those in Plan-1. There were significant differences in Dmax and V50 of the rectum and V50 of the bladder between Plan-1 and Plan-2(P=0.040; P=0.000; P=0.047). Compared with Plan-1, there were statistical differences in inter-fractional Dmax and V50 during the initial treatment (P=0.047, 0.037), and V50 of the rectum within the 13th to 21st radiotherapy, respectively (P=0.009, 0.017, 0.028). Besides, differences regarding Vmax and V50 in the initial treatment and the 21st to 23rd radiotherapy were close to the statistical significance when compared to those in Plan-1, respectively (P=0.061, 0.053; P=0.072, 0.058). Conclusions IGRT can reduce the radiation doses and volumes of the rectum and bladder, especially the rectum. The therapeutic plan should be rescheduled when tumor retraction is evident at half of the total radiation dose (around 13th fraction) in external beam radiotherapy. If it is difficult to achieve image guidance in each treatment, selective image guidance could be performed to effectively reduce the injuries of the rectum and bladder. Key words: Cervical neoplasms/image-guided radiotherapy; Cervical neoplasms/helical tomotherapy; Dosimetry

14: Current Practice of Brachytherapy and External Beam Radiotherapy for Cervical Cancer in Ontario, Canada

14: Current Practice of Brachytherapy and External Beam Radiotherapy for Cervical Cancer in Ontario, Canada

SU-E-J-61: Monitoring Tumor Motion in Real-Time with EPID Imaging During Cervical Cancer Treatment

Purpose: Traditional external beam radiotherapy for cervical cancer requires setup by external skin marks. In order to improve treatment accuracy and reduce planning margin for more conformal therapy, it is essential to monitor tumor positions interfractionally and intrafractionally. We demonstrate feasibility of monitoring cervical tumor motion online using EPID imaging from Beam’s Eye View. Methods: Prior to treatment, 1∼2 cylindrical radio opaque markers were implanted into inferior aspect of cervix tumor. During external beam treatments on a Varian 2100C by 4-field 3D plans, treatment beam images were acquired continuously by an EPID. A Matlab program was developed to locate internal markers on MV images. Based on 2D marker positions obtained from different treatment fields, their 3D positions were estimated for every treatment fraction. Results: There were 398 images acquired during different treatment fractions of three cervical cancer patients. Markers were successfully located on every frame of image at an analysis speed of about 1 second per frame. Intrafraction motions were evaluated by comparing marker positions relative to the position on the first frame of image. The maximum intrafraction motion of the markers was 1.6 mm. Interfraction motions were evaluated by comparing 3D marker positions at different treatment fractions. The maximummore » interfraction motion was up to 10 mm. Careful comparison found that this is due to patient positioning since the bony structures shifted with the markers. Conclusion: This method provides a cost-free and simple solution for online tumor tracking for cervical cancer treatment since it is feasible to acquire and export EPID images with fast analysis in real time. This method does not need any extra equipment or deliver extra dose to patients. The online tumor motion information will be very useful to reduce planning margins and improve treatment accuracy, which is particularly important for SBRT treatment with long delivery time.« less

Comparing intensity-modulated radiotherapy and conventional external beam radiotherapy in cervical cancer

Comparing intensity-modulated radiotherapy and conventional external beam radiotherapy in cervical cancer

Comparing intensity modulated radiotherapy and conventional external beam radiotherapy in cervical cancer.

5610 Background: To compare Intensity-modulated radiation therapy (IMRT) with conventional external beam radiation therapy (CXRT) regarding morbidity, tumor response, and quality of life (QOL) in cervical cancer patients. Methods: Between 8/2009-2/2010, 50 patients (pts) with age range 20-85, with FIGO Stage IIA- IIIB were prospectively randomized 2:1 to CXRT and IMRT at Indo-American Cancer Institute. Both groups received concurrent chemotherapy (weekly cisplatin 30-40mg/m2) with external beam radiation (EBRT), 50Gy/25fractions followed by intracavitary brachytherapy at 21Gy/3fractions. Complications and QOL were evaluated during treatment and in follow-up with CTC 4.0 and EORTC QLQ-C30, and disease recurrence was based on pelvic exam. Analysis used Chi square(X2) at a significance level of 0.05. Results: Average time to completion was 49 and 48 days in CXRT and IMRT arms (p&gt;.05). Four pts did not complete the treatment in the CXRT. Two months after completion 31/35 (89%) of CXRT and 15/15 (100%) of IMRT had complete response (p&gt;.05). At 5 months, 30/35 (86%) of CXRT, and 14/15 (100%) of IMRT had no loco-regional disease (LRD); 1 IMRT pt died from distant metastasis (DM). At 18 months, 25/35 (72%) in CXRT and 14/15 (93.5%) in IMRT had no LRD or DM. Most common acute side effects in the CXRT were Grade 1 vomiting/cystitis/diarrhea and Grade 2 nausea/skin reactions/proctitis. One pt developed vesicovaginal fistula (VVF) after 50Gy by EBRT. Most common acute side effects in the IMRT were Grade1 nausea/vomiting/cystitis/proctitis/diarrhea. Two pts had grade 3 neutropenia in the 5th week of RT. QOL was better in IMRT (p &lt;.01) based on functional, symptom, single items, and global scales except for pain, insomnia, loss of appetite. Diarrhea, financial problems were worse in the CXRT (p&lt;.05). Chronic complications such as radiation induced proctitis in 5 patients, and sub-acute intestinal obstruction in 2 patients during follow-up period in CXRT vs. IMRT (p &lt; 0.001). Conclusions: IMRT is superior to CXRT with fewer chronic side effects and similar acute side effects and treatment responses. This is the first randomized clinical trial of these treatments in cervical cancer.

Intermediate-term results of image-guided brachytherapy and high-technology external beam radiotherapy in cervical cancer: Chiang Mai University experience

ObjectiveTo evaluate the outcomes of image-guided brachytherapy combined with 3D conformal or intensity modulated external beam radiotherapy (3D CRT/IMRT) in cervical cancer at Chiang Mai University. MethodsFrom 2008 to 2011, forty-seven patients with locally advanced cervical cancer were enrolled in this study. All patients received high-technology (3D CRT/IMRT) whole pelvic radiotherapy with a total dose of 45–46Gy plus image-guided High-Dose-Rate intracavitary brachytherapy 6.5–7Gy×4 fractions to a High-Risk Clinical Target Volume (HR-CTV) according to GEC-ESTRO recommendations. The dose parameters of the HR-CTV for bladder, rectum and sigmoid colon were recorded, as well as toxicity profiles. In addition, the endpoints for local control, disease-free, metastasis-free survival and overall survival were calculated. ResultsAt the median follow-up time of 26months, the local control, disease-free survival, and overall survival rates were 97.9%, 85.1%, and 93.6%, respectively. The mean dose of HR-CTV, bladder, rectum and sigmoid were 93.1, 88.2, 69.6, and 72Gy, respectively. In terms of late toxicity, the incidence of grade 3–4 bladder and rectum morbidity was 2.1% and 2.1%, respectively. ConclusionsA combination of image-guided brachytherapy and IMRT/3D CRT showed very promising results of local control, disease-free survival, metastasis-free survival and overall survival rates. It also caused a low incidence of grade 3–4 toxicity in treated study patients.

Dosimetric comparison between conventional and conformal radiotherapy for carcinoma cervix: Are we treating the right volumes?

Background and Purpose:Conventional portals, based on bony anatomy, for external beam radiotherapy for cervical cancer have been repeatedly demonstrated as inadequate. Conversely, with image-based conformal radiotherapy, better target coverage may be offset by the greater toxicities and poorer compliance associated with treating larger volumes. This study was meant to dosimetrically compare conformal and conventional radiotherapy.Materials and Methods:Five patients of carcinoma cervix underwent planning CT scan with IV contrast and targets, and organs at risk (OAR) were contoured. Two sets of plans-conventional and conformal were generated for each patient. Field sizes were recorded, and dose volume histograms of both sets of plans were generated and compared on the basis of target coverage and OAR sparing.Results:Target coverage was significantly improved with conformal plans though field sizes required were significantly larger. On the other hand, dose homogeneity was not significantly improved. Doses to the OARs (rectum, urinary bladder, and small bowel) were not significantly different across the 2 arms.Conclusion:Three-dimensional conformal radiotherapy gives significantly better target coverage, which may translate into better local control and survival. On the other hand, it also requires significantly larger field sizes though doses to the OARs are not significantly increased.

Cervical Cancer Regression Measured Using Weekly Magnetic Resonance Imaging During Fractionated Radiotherapy: Radiobiologic Modeling and Correlation With Tumor Hypoxia

To measure regression of cancer of the uterine cervix during external beam radiotherapy using magnetic resonance imaging, derive radiobiologic parameters from a mathematical model of tumor regression, and compare these parameters with the pretreatment measurements of tumor hypoxia. A total of 27 eligible patients undergoing external beam radiotherapy for cervical cancer underwent weekly magnetic resonance imaging scans. The tumor volume was assessed on each of these scans and the rate of regression plotted. A radiobiologic model was formulated to simulate the effect on tumor regression of the surviving proportion of cells after 2 Gy (SP(2)), the cell clearance constant (clearance of irreparably damaged cells from the tumor [T(c)]), and accelerated repopulation. Nonlinear regression analysis was used to fit the radiobiologic model to the magnetic resonance imaging-derived tumor volumes and to derive the estimates of SP(2) and T(c) for each patient. These were compared to the pretreatment hypoxia measurements. The initial tumor volume was 8-209 cm(3). The relative reduction in volume during treatment was 0.02-0.79. The simulations using representative values of the independent biologic variables derived from published data showed SP(2) and T(c) to strongly influence the shape of the volume-response curves. Nonlinear regression analysis yielded a median SP(2) of 0.71 and median T(c) of 10 days. Tumors with a high SP(2) >0.71 were significantly more hypoxic at diagnosis (p = 0.02). The results of our study have shown that cervical cancer regresses during external beam radiotherapy, although marked variability is present among patients and is influenced by underlying biologic processes, including cellular sensitivity to radiotherapy and proliferation. Better understanding of the biologic mechanisms might facilitate novel adaptive treatment strategies in future studies.

Radiation dose to laterally transposed ovaries during external beam radiotherapy for cervical cancer

The purpose of this study was to estimate the radiation dose to laterally transposed ovaries from external beam radiotherapy for cervical cancer. Dose measurements were performed in a modified humanoid phantom using a 6 MV photon beam. The dependence of the ovarian dose upon the field size, the distance from the primary irradiation field and the presence of wedges or gonadal shielding was determined. For a tumor dose of 45 Gy, ovarian dose was 0.88–8.51 Gy depending on the field size employed and the location of the transposed ovary in respect to the treatment field. Positioning of 7 cm thick shielding reduced the dose to ovary by less than 19%. The use of wedges increased the ovarian dose by a factor up to 1.5. Accurate radiographic localization of the ovaries allows the use of the presented dosimetric results to obtain a reasonable prediction of the ovarian dose.