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Dysphagia is common in patients presenting with oesophageal malignancy. This study aimed to determine the clinical effectiveness of biodegradable stents to help with malignant dysphagia due to radiotherapy for oesophageal cancer and furthermore to establish the complication and re-intervention rates associated with their use.
This was a retrospective, observational study of 22 patients between 2008 and 2013. Complications within 2 weeks and episodes of re-intervention required within 4 months of stent insertion prior to radiotherapy were recorded.
Pre-stent insertion, the mean O’Rourke dysphagia score was 3·5 (median 3, range 2–5). This improved to a mean score of 2·8 (median 3, range 1–4) 1–3 weeks following stent insertion. Complications occurred in seven patients (32%) in an immediate 2-week period, including: pain (2), dysphagia requiring dilatation (1), food obstruction not requiring intervention (1), food obstruction requiring intervention (2) and upper gastrointestinal bleed not requiring intervention (1). Re-intervention was required in 18% within a 4-month period.
We propose that biodegradable oesophageal stents are safe and may have benefit over self-expanding metal stents. We recommend they are placed alongside a radiologically inserted gastrostomy in a combined procedure prior to radiotherapy planning.
It has been shown that patients with a greater tumour volume have poorer outcomes following definitive radiotherapy but its exact role remains unclear. The purpose of this study is to investigate the role of tumour volume as a prognostic indicator in non-small cell lung cancer (NSCLC) patients treated with definitive radiotherapy in a single institution over 10 years.
In total, 167 patients with NSCLC treated by definitive (chemo)radiotherapy were retrospectively reviewed between 2006 and 2015. Patient demographics, disease characteristics and tumour volume parameters were collected. Univariate analyses were carried out using Kaplan–Meier survival curves to assess the association of potential prognostic factors with the primary endpoints of overall survival (OS) rates and locoregional recurrence rates. Multivariate analyses were carried out using a Cox regression method.
The median total tumour volume (TTV), defined as the gross tumour volume plus the volume of involved nodes, was 103 cm3. Patients were divided into small and large tumour groups based on this median. OS rates at 1, 3 and 5 years for smaller volumes were 69%, 24% and 13% and for larger volumes 48%, 14% and 8%, respectively. On univariate survival analyses larger TTV was significantly associated with poorer OS (p = 0·019). The concurrent use of chemotherapy significantly improved survival (p = 0·026). Nodal involvement (p = 0·03) and Eastern Cooperative Oncology Group performance status (p < 0·001) were also significant independent prognostic factors of OS. On multivariate analysis TTV was strongly predictive of survival (p = 0·03; hazard ratio 1·702, 95% confidence interval 1·198–2·415). There was no association between nodal volume, tumour stages, overall stage, age, histology and radiation dose with any of the primary endpoints.
TTV is a significant prognostic factor in patients with advanced NSCLC treated by radical radiotherapy. In this cohort of patients TTV is more reliable at predicting survival than T stage and overall stage.
The mandatory clinical radiotherapy department visit undertaken by potential applicants aims to provide understanding of the profession and therefore reduce attrition. Increasing pressure on clinical departments makes visits a logistical challenge. This additional step may also present as an unnecessary barrier to applicants. With no evidence relating to visits, this study aimed to explore the perceptions of both students and clinical educators concerning potential benefits and challenges.
A focus group interview method was used to gather in-depth qualitative data concerning the clinical department visit experiences from first-year undergraduate students and clinical educators.
Three themes emerged from the student focus groups: the perceived purpose of the clinical visit, the visit content and the outcomes and impact arising from the visit. Clinical educator data also followed these themes in addition to ‘logistical impact’ theme.
The clinical visit has value to applicants in affirming their decision to study radiotherapy. There is variation in expectation and content for these visits and they are logistically challenging. Nationally agreed guidelines for visit structure and content could improve visit efficiency and effectiveness. A national clinical visit form may reduce workload for educators and applicants.
This study will evaluate radiation medicine professionals’ perceptions of clinical and professional risks and benefits, and the evolving roles and responsibilities with artificial intelligence (AI).
Radiation oncologists (ROs), medical physicists (MPs), treatment planners (TP-RTTs) and treatment delivery radiation therapists (TD-RTTs) at a cancer centre in preliminary stages of implementing an AI-enabled treatment planning system were invited to participate in uniprofessional focus groups. Semi-structured scripts addressed the perceptions of AI, including thoughts regarding changing roles and competencies. Sessions were audiorecorded, transcribed and coded thematically through consensus-building.
A total of 24 participants (four ROs, five MPs, seven TP-RTTs and eight TD-RTTs) were engaged in four focus groups of 58 minutes average duration (range 54–61 minutes). Emergent themes addressed AI’s impact on quality of care, changing professional tasks and changing competency requirements. Time-consuming repetitive tasks such as delineating targets, generating treatment plans and quality assurance were thought conducive to offloading to AI. Outcomes data and adaptive planning would be incorporated into clinical decision-making. Changing workload would necessitate changing skills, prioritising plan evaluation over generation and increasing interprofessional communication. All groups discussed AI reducing the need for TP-RTTs, though displacement was thought more likely than replacement.
It is important to consider how professionals perceive AI to be proactive in informing change, as gains in quality and efficiency will require new workflows, skills and education.
The purpose of this study was to evaluate the dosimetric impact of multileaf collimator (MLC) positional errors on dynamic intensity-modulated radiotherapy (IMRT) treatments through planning simulation. Secondly the sensitivity of IMRT MatriXX device for detecting the MLC leaf positional errors was also evaluated.
Materials and methods
In this study five dynamic IMRT plans, each for brain and head–neck (HN), were retrospectively included. An in-house software was used to introduce random errors (uniform distribution between −2·0 and +2·0 mm) and systematic errors [±0·5, ±0·75, ±1·0 and ±2·0 mm (+: open MLC error and −: close MLC error)]. The error-introduced MLC files were imported into the treatment planning system and new dose distributions were calculated. Furthermore, the dose–volume histogram files of all plans were exported to in-house software for equivalent uniform dose (EUD), tumour control probability and normal tissue complication probability calculations. The error-introduced plans were also delivered on LINAC, and the planar fluences were measured by IMRT MatriXX. Further, 3%/3 mm and 2%/2 mm γ-criteria were used for analysis.
In planning simulation study, the impact of random errors was negligible and ΔEUD was <0·5±0·7%, for both brain and HN. The impact of systematic errors was substantial, and on average, the maximum change in EUD for systematic errors (close 2 mm) was −10·7±3·1% for brain and −15·5±2·6% for HN.
It can be concluded that the acceptable systematic error was 0·4 mm for brain and 0·3 mm for HN. Furthermore, IMRT MatriXX device was able to detect the MLC errors ≥2 mm in HN and >3 mm errors in brain with 2%/2 mm γ-criteria.
The novel Volumetric Image Matching Environment for Radiotherapy (VIMER) was developed to allow users to view both computed tomography (CT) and cone-beam CT (CBCT) datasets within the same 3D model in virtual reality (VR) space. Stereoscopic visualisation of both datasets combined with custom slicing tools and complete freedom in motion enables alternative inspection and matching of the datasets for image-guided radiotherapy (IGRT).
Material and methods:
A qualitative study was conducted to explore the challenges and benefits of VIMER with respect to image registration. Following training and use of the software, an interview session was conducted with a sample group of six university staff members with clinical experience in image matching.
User discomfort and frustration stemmed from unfamiliarity with the drastically different input tools and matching interface. As the primary advantage, the users reported match inspection efficiency when presented with the 3D volumetric renderings of the planning and secondary CBCT datasets.
This study provided initial evidence for the achievable benefits and limitations to consider when implementing a 3D voxel-based dataset comparison VR tool including a need for extensive training and the minimal interruption to IGRT workflow. Key advantages include efficient 3D anatomical interpretation and the capability for volumetric matching.
The authors proposed a novel perimeter-based index (PBI) that was capable of evaluating the accuracy in the appraisal of auto-segmentation software. A quantitative value, that is time saved in editing the auto-segmented contours, was used to compare the effectiveness of two other commonly used indices in this study.
The relationship between the proposed index and the amount of the contouring time that could be saved was studied. The performances of two other commonly used similarity indices, namely Dice similarity coefficient (DSC) and the modified normalised average Hausdorff distance (MNAHD), were also evaluated. Ten nasopharyngeal cases and ten prostate cases that were previously treated with intensity-modulated radiation therapy technique were recruited as the validation cases in this study. Three observers were invited to contour four structures (bladder, rectum, brain stem and parotid gland) on computed tomography images of the validation cases without any aids. The time taken for contouring was recorded as the manual contouring time. By using an atlas-based auto-segmentation software, three sets of contours were generated for each validation case with different library sizes to produce different degrees of similarity level. The values of the three similarity indices of the auto-segmented contours were calculated. The observers were asked to edit the auto-segmented contours and the editing time was recorded.
The correlation between the editing time and the similarity indices was studied. The amount of time saved was calculated by subtracting the editing time from the manual contouring time. The performances of PBI, DSC and MNAHD were evaluated using Pearson correlation coefficient and receiver operating curve (ROC) analysis.
The PBI showed a positive linear relationship with the amount of contouring time saved. Pearson correlation coefficient ranged from 0·73 to 0·86 for the four structures. The PBI had a stronger correlation than the DSC in bladder and parotid gland, while there was no significant difference between the two indices in rectum and brain stem. The MNAHD had an inferior correlation than the proposed index. For the ROC analysis, the cut-off values for the PBI were 0·549, 0·401 and 0·301 for the three levels of contouring time saved, namely 50, 25 and 0%, respectively. The accuracy of PBI was over 77% and the Youden index was >0·6 for all three levels.
The proposed index showed a stronger relationship to the amount of contouring time saved. It was a simple tool that could be used to evaluate the performance of different segmentation algorithms.
There is abundant evidence of the comparative efficacy of single-fraction (SF) radiotherapy and multi-fraction (MF) radiotherapy when treating patients with bone metastases. Despite this, previous surveys have shown SF schedules to be underutilised.
To determine current patterns of practice in patients with bone metastasis and to investigate the factors that influence practice.
An electronic audit was performed amongst 46 physicians, within 7 hospital trusts in the UK. The audit comprised of four hypothetical cases in which consultants and registrars chose which dose and fractionation they would recommend and their reasons for this recommendation.
SF radiotherapy was the most common radiotherapy schedule in hypothetical cases 1, 3 and 4. SF radiotherapy was recommended by 65% of respondents in case 1, 47% in case 2, 89% in case 3 and 46% in case 4. For case 2, 50% proposed MF radiotherapy. For case 4, 22% of respondents recommended Stereotactic Body Radiotherapy (SABR). The following deciding factors were cited as influencing choice of an SF schedule: prognosis, published evidence, performance status and spinal cord compression.
The most common radiotherapy schedule selected was SF. However, there were inter-institution differences regarding the use of SF radiotherapy. Furthermore, the survey had shown that a third of respondents recommended an MF regime, despite evidence supporting the efficacy of an SF schedule.
This study is a dosimetric and acute toxicity comparison of endometrial cancer patients treated with either Axxent (Xoft, Inc., San José, CA, USA) electronic and interstitial brachytherapy versus interstitial high dose rate brachytherapy (HDRBT).
Materials and Methods
Between 2015 and 2017, 94 patients with postoperative endometrial cancer were treated in our centre with the Axxent electronic brachytherapy (eBT) system. The V150 and V200 are evaluated prospectively for each plan. The mean age of patients was 65.9 years (age range 33–84 years), with different tumour staging. Of the 94 patients, 37 received exclusive adjuvant brachytherapy (25 Gy in five sessions); the remaining patients received external beam radiotherapy (EBRT) with a regimen of 23 sessions of 2 Gy each to the entire pelvis, followed by eBT (15 Gy in three sessions). Additionally, the absorbed doses received by the organs at risk (OAR), urinary bladder, rectum and sigmoid colon were compared with HDRBT plans, evaluating D2cc, V50% and V35%. Median follow-up was done for each of the 94 patients to assess the toxicity of the treatment: vaginal mucosa toxicity, rectal and urinary toxicity; and results are presented for acute toxicity, toxicity at 1 month after the end of treatment and follow-up after 12 months for a portion of patients according to the Radiation Therapy Oncology Group (RTOG) toxicity criteria.
The doses in OAR for eBT plans were lower than that for HDRBT plans, both Ir-192 and Co-60 plans, whose doses were similar. The dose in bladder with eBT was 63.8% of the prescribed dose for D2cc versus 70.1% for HDRBT Ir-192, for V50% was 7.2% versus 12.7% and for V35% was 15.2% versus 28.2%. In rectum the D2cc was 61.2% versus 68.4%, for V50% was 7.9% versus 14.3% and for V35% was 16.7% versus 32%. Results demonstrated lower doses to OAR in all eBT plans. Acute toxicity in eBT was very low in cases of mucositis, with only one case of toxicity greater than grade 1, rectal toxicity and urinary toxicity; results at 1 month are equally good, toxicity symptoms disappeared and no relapses have occurred to date.
The results of treatment with the Axxent eBT unit for 94 patients are very good, as no recurrence has been observed and the toxicity of the treatment is very low. The increase in V150 and V200 has not produced an increase in vaginal mucosa toxicity, and the doses in the OAR are lower than in the plans implemented for HDRBT with Ir-192 or Co-60. eBT is a good alternative to treat endometrial cancer in centres without conventional HDR availability. To date, there are limited published studies reporting on outcomes from patients treated with eBT.
Dose distribution index (DDI) is a treatment planning evaluation parameter, reflecting dosimetric information of target coverage that can help to spare organs at risk (OARs) and remaining volume at risk (RVR). The index has been used to evaluate and compare prostate volumetric modulated arc therapy (VMAT) plans using two different plan optimisers, namely photon optimisation (PO) and its predecessor, progressive resolution optimisation (PRO).
Materials and methods:
Twenty prostate VMAT treatment plans were created using the PO and PRO in this retrospective study. The 6 MV photon beams and a dose prescription of 78 Gy/39 fractions were used in plans with the same dose–volume criteria for plan optimisation. Dose–volume histograms (DVHs) of the planning target volume (PTV), as well as of OARs such as the rectum, bladder, left and right femur were determined in each plan. DDIs were calculated and compared for plans created by the PO and PRO based on DVHs of the PTV and all OARs.
The mean DDI values were 0·784 and 0·810 for prostate VMAT plans created by the PO and PRO, respectively. It was found that the DDI of the PRO plan was about 3·3% larger than the PO plan, which means that the dose distribution of the target coverage and sparing of OARs in the PRO plan was slightly better. Changing the weighting factors in different OARs would vary the DDI value by ∼7%. However, for plan comparison based on the same set of dose–volume criteria, the effect of weighting factor can be neglected because they were the same in the PO and PRO.
Based on the very similar DDI values calculated from the PO and PRO plans, with the DDI value in the PRO plan slightly larger than that of the PO, it may be concluded that the PRO can create a prostate VMAT plan with slightly better dose distribution regarding the target coverage and sparing of OARs. Moreover, we found that the DDI is a simple and comprehensive dose–volume parameter for plan evaluation considering the target, OARs and RVR.
To quantify the relationship between the planning target volume (PTV) dose homogeneity and organs at risk (OARs) sparing in correlation with anatomical parameters in prostate intensity-modulated radiotherapy (IMRT).
Materials and methods
Nine IMRT plans with various target dose constraints’ priorities were created for 15 prostate cancer patients. Selected PTV and OARs parameters were calculated for the patients. A trade-off was assessed between homogeneity index (HI) and OAR sparing. Several anatomical parameters were evaluated to investigate their effects on the OAR sparing and HI.
Inverse exponential relationships were found between the OAR sparing and HI (average R2 of 0·983 and 0·994 for bladder and rectum, respectively). Decreasing the priority led to more OARs sparing (normal tissue complication probability reduction: 97·6 and 74·5%; mean dose reduction: 16·3 and 11·3% for bladder and rectum, respectively) and worsening of the HI (0·095–0·322) but with no significant effect on tumour control probability. Furthermore, OARs volumes, distances between OARs and PTV and their joint volumes had stronger correlations with OARs’ mean doses.
Enforcement of target dose constraints was more effective on the improvement of HIs for the patients with initial high HI values at low dose constraints’ priorities. Reducing the priority had more effects on the OARs sparing compared to HI, especially for the patients with high OAR doses in high priority plans. This can be attributed to smaller distances or greater joint volumes between the OARs and PTV.
Radiotherapy clinical trials are at the forefront of modern-day prostate cancer patient management. Patients are reviewed during treatment by clinical oncologists or competent on-treatment review radiographers to minimise treatment toxicities. Clinical Research Radiographers (CRRs) routinely monitor and gather research data from patients participating in clinical trials.
The aim of this article is to evaluate the effectiveness of the CRR undertaking the on-treatment review of clinical trial patients.
An experienced CRR within the Northern Ireland Cancer Trials Network was supervised by a clinical oncologist to undertake the role of the on-treatment review of patients receiving radiotherapy for prostate cancer. The CRR explored published literature and compiled this written evaluation as part of their advanced practice learning.
The supervising clinical oncologist verified, following the planned period of supervised practice and academic study, that the CRR was competent to fulfil the role. Evidence of the beneficial synergistic impact of co-joining the roles was experienced at first hand during the undertaking of supervised practice.
Co-joining the roles and responsibilities of the CRR and the on-treatment review radiographer enhanced the quality of care offered to the patients participating in clinical trials.
This study reported the justification and selection of acceptable γ criteria with respect to low (6 MV) and high (15 MV) photon beams for intensity-modulated radiation therapy quality assurance (IMRT QA) using the Gafchromic external beam therapy 3 (EBT3) film.
Materials and methods
Five-field step-and-shoot IMRT was used to treat 16 brain IMRT patients using the dual-energy DHX-S linear accelerator (Varian Medical System, Palo Alto, CA, USA). Dose comparisons between computed values of the treatment planning system (TPS) and Gafchromic EBT3 film were evaluated based on γ analysis using the Film QA Pro software. The dose distribution was analysed with gamma area histograms (GAHs) generated using different γ criteria (3%/2 mm, 3%/3 mm and 5%/3 mm) for the 6 and 15 MV photon beams, to optimise the best distance-to-agreement (DTA) criteria with respect to the beam energy.
From the comparison between the dose distributions acquired from the TPS and EBT3 film, a DTA criterion of 3%/2 mm showed less dose differences (DDs) with passing rates up to 93% for the 6 MV photon beams, while for the 15 MV a relaxed DTA criterion of 5%/3 mm was consistent with the DD acceptability criteria with a 95% passing rate.
Our results suggested that high-energy photon beams required relaxed DTA criteria for the brain IMRT QA, while low-energy photon beams showed better results even with tight DTA criteria.
Re-planning mid-treatment, with the adjustment of target volumes, has been performed as part of the normal workflow at our institution. We sought to quantify the benefit of this approach and identify factors to optimise plan adaptive strategies.
Materials and methods:
Patients with locally advanced oropharyngeal cancer treated to 70 Gy with concurrent chemoradiation (CCRT) on TomoTherapy® who underwent re-planning during the treatment were eligible. Survival and prognostic factors were evaluated with Kaplan–Meier and Cox proportional hazards, two-side p-value <0·05 significant.
Forty-two patients were identified with Stage III (n = 5), IVA (n = 34) and IVB (n = 3) [AJCC 7th] disease. Median re-planning dose was 40 Gy (14–60 Gy). Median change in mean total parotid dose was reduction of 1 Gy (range –7·5 Gy to +13·9 Gy). The volume of PTV70 and PTV60 receiving 99% of the prescribed (V99) dose was increased by 2·2% (–3·3 to +16·6%) and 1·9% (–11·5 to +12·6%) by re-planning. As a continuous variable, increasing per cent nodal regression was associated with the improved disease control in a multivariate model including stage, pack years smoking and human papilloma viral (HPV) status (HR: 0·85, 0·71–0·99, p = 0·05).
Adaptive planning generates a superior plan for the majority of patients, but there is modest overall parotid gland sparing.
The purpose of this study is the verification of intensity modulated radiation therapy (IMRT) head neck treatment planning with one-dimensional and two-dimensional (2D) dosimeters using imaging and radiation oncology core (IROC) Houston head & neck (H&N) phantom.
The image of the H&N phantom was obtained by computed tomography scan which was then transferred to Pinnacle@3 treatment planning system (TPS) for treatment planning. The contouring of the target volumes and critical organ were done manually and dose constraints were set for each organ according to IROC prescription. The plan was optimised by adoptive convolution algorithm to meet the IROC criteria and collapse cone convolution algorithm calculated the delivered doses for treatment. Varian Clinac 2110 was used to deliver the treatment plan to the phantom, the process of irradiation and measurement were repeated three times for reproducibility and reliability. The treatment plan was verified by measuring the doses from thermoluminescent dosimeters (TLDs) and GafChromic external beam therapy 2 films. The agreement between the planned and delivered doses were checked by calculating the percentage dose differences, analysing their isodose line profiles and 2D gamma maps.
The average percent dose difference of 1·8% was obtained between computed doses by TPS and measured doses from TLDs, however these differences were found to be higher for organ at risk. The film dose profile was well in agreement with the planned dose distribution with distance to agreement of 1·5 mm. The gamma analysis of the computed and recorded doses passed the criteria of 3%/3 mm with passing percentages of >96%, which shows successful authentication of delivered doses for IMRT.
IMRT pre-treatment validation can be done with IROC anthropomorphic phantoms, which is essential for the delivery of modulated radiotherapies. It was concluded that films and TLDs can be used as quality assurance tools for IMRT.
Weekly low-dose cisplatin is routinely used in concurrent chemoradiation (CCRT) in locally advanced head and neck cancer (LAHNC), despite 3-weekly cisplatin being the standard of care. We compared compliance, toxicity and efficacy in weekly versus 3-weekly cisplatin CCRT in LAHNC.
Materials and methods
In this retrospective study, weekly cisplatin 50 mg flat dose was compared with 3-weekly cisplatin 100 mg/m2, when given in CCRT in LAHNC with curative intent. The study outcome was compliance, toxicity, loco-regional control (LRC), disease-free survival (DFS) and overall survival (OS).
Eighty-four patients received CCRT from January 2013 to June 2017, 40 in weekly and 44 in 3-weekly arm. There was no difference between the arms not completing scheduled radiation therapy or chemotherapy. Patient receiving 200 mg/m2 cisplatin is higher in 3-weekly arm compared with weekly arm (75 versus 40·9%; p<0·0015). Compared with 3-weekly arm, more patient in weekly arm developed grade ≥3 mucositis (52·5 versus 15·9%, p=0·0004), day care intravenous hydration (82·5 versus 38·6% <0·0001) and in-patient admission (55·0 versus 18·2%; p=0·0004). The 2-year LRC, DFS and OS in weekly versus 3-weekly arm were: 70 versus 61·4% (p=0·406); 67·5 versus 56·8% (p=0·314); 67·5 versus 61·4% (p=0·558), respectively. The median time to LRR, DFs and OS was not reached.
Weekly cisplatin is comparable with 3-weekly cisplatin in terms of compliance, disease control and survival, but with increased grade 3 mucositis and higher admissions for supportive care.