Radiotherapy during the COVID-19: a review about management and treatment strategies.

Background: The administration of radiotherapy should be encouraged despite the emergency of COVID-19; therefore, our aim is to analyze management and therapeutic interventions to be implemented in a Radiotherapy department to allow patients to continue their treatment and health professionals to continue their work safely. Materials and methods: A Pubmed search was performed, in which all articles specific to Radiotherapy and COVID-19 were included. Those articles that were too specific about the COVID-19, surgery and chemiotherapy, were excluded. Results: 315 articles were selected, of which 35 were about therapeutic strategies and 25 about management strategies. In the first category, 5 articles were about how radiotherapy could be a weapon to be used for COVID-19 positive patients with important lung problems. While 30 articles described priorities and new treatment plans for oncology patients who have to undergo radiotherapy during the pandemic. In the second category, almost all the articles explained how triage can be a preventive and monitoring way against COVID-19 in an operating unit with many patients and professionals, and other articles developed a telemedicine system, too, which allows patients to make scheduled visits without coming to the hospital and also for the staff, who can work remotely. In addition, 5 articles concerning psychological aspects of both patients and health care providers were included. Conclusion: This document can be used as a summary in the coming months/years, during the recovery phase from COVID-19 pandemic outbreak and as a starting point to be used in case of further pandemic break-out.

A review of the Best Practice in Radiation Oncology project from 2008 to 2018.

The European Society of Radiotherapy and Oncology (ESTRO)/International Atomic Energy Agency (IAEA) Best Practice in Radiation Oncology-a project to train RTT trainers has reached its ten year anniversary and will commence its fifth iteration in 2018. This project commenced as a novel way to address the issue of limited RTT education throughout Europe. In many countries the profession of RTT is not officially recognised and there is no formal education programme. RTT education is frequently a very short component of a broader programme such as diagnostic imaging, nursing or a technical discipline. To date, fifty-nine short courses have been delivered, two RTT-specific National societies have been developed, a South East European cooperation with biannual conferences has evolved and significant progress has been made on improving the radiotherapy-specific content of national educational programmes, which will continue with future iterations of this project.

ESTRO ACROP guidelines for positioning, immobilisation and position verification of head and neck patients for radiation therapists.

BACKGROUND AND PURPOSE: Over the last decade, the management of locally advanced head and neck cancers (HNCs) has seen a substantial increase in the use of chemoradiation. These guidelines have been developed to assist Radiation TherapisTs (RTTs) in positioning, immobilisation and position verification for head and neck cancer patients. MATERIALS AND METHODS: A critical review of the literature was undertaken by the writing committee.Based on the literature review, a survey was developed to ascertain the current positioning, immobilisation and position verification methods for head and neck radiation therapy across Europe. The survey was translated into Italian, German, Greek, Portuguese, Russian, Croatian, French and Spanish.Guidelines were subsequently developed by the writing committee. RESULTS: Results from the survey indicated that a wide variety of treatment practices and treatment verification protocols are in operation for head and neck cancer patients across Europe currently.The guidelines developed are based on the experience and expertise of the writing committee, remaining cognisant of the variations in imaging and immobilisation techniques used currently in Europe. CONCLUSIONS: These guidelines have been developed to provide RTTs with guidance on positioning, immobilisation and position verification of HNC patients. The guidelines will also provide RTTs with the means to critically reflect on their own daily clinical practice with this patient group.

Beyond geometrical overlap: a Dosimetrical Evaluation of automated volumes Adaptation (DEA) in head and neck replanning.

INTRODUCTION: Automated target volumes adaptation could be useful in H&N replanning, but its dosimetric impact has not been analyzed.Primary aim of this investigation is dose coverage assessment in fully automated and edited PTV adaptation settings, compared to manual benchmark. MATERIALS AND METHODS: Ten IMRT patients were selected and replanning CTs were acquired.A deformable registration with PTV adaptation was performed defining PTVA.PTV B was obtained through manual editing and a benchmark PTV C was manually segmented by a delineation team.The Dice Similarity Index (DSI) and the mean Hausdorff Distance (mHD) were calculated between PTV A and PTV C, and between PTV B and PTV C.One IMRT plan was realized for each PTV: the plans optimized on PTV A and PTV B were proposed on PTV C to evaluate their dosimetric reliability compared to the benchmark plan in terms of PTV V95% dose coverage. RESULTS: The comparisons between PTV A with PTV C and PTV B with PTV C showed that the better DSI (high) and mHD values (low) are, the smaller difference when compared to PTV C V95% is described.Evaluating plan A and B, PTV C V95% reduced by 6.1 ± 3.0% and by 4.1 ± 2.3% respectively when compared to plan C PTV C V95%.PTV B reaches acceptable dose coverage values (PTV V95% >95%) when DSI is >0.91 and a mHD < 0.17 mm and it has better results when compared to PTV A in 70%. DISCUSSION: The results show a correlation between the DSI-mHD and the PTV V95% variation, in the comparisons PTV A and PTV B vs PTV C.Furthermore, we observed that PTV V95% coverage is higher in PTV B than in PTV A: the use of automated propagation may not be definitive and requires manual correction.

Automatic segmentation software in locally advanced rectal cancer: READY (REsearch program in Auto Delineation sYstem)-RECTAL 02: prospective study.

To validate autocontouring software (AS) in a clinical practice including a two steps delineation quality assurance (QA) procedure.The existing delineation agreement among experts for rectal cancer and the overlap and time criteria that have to be verified to allow the use of AS were defined.Median Dice Similarity Coefficient (MDSC), Mean slicewise Hausdorff Distances (MSHD) and Total-Time saving (TT) were analyzed.Two expert Radiation Oncologists reviewed CT-scans of 44 patients and agreed the reference-CTV: the first 14 consecutive cases were used to populate the software Atlas and 30 were used as Test.Each expert performed a manual (group A) and an automatic delineation (group B) of 15 Test patients.The delineations were compared with the reference contours.The overlap between the manual and automatic delineations with MDSC and MSHD and the TT were analyzed.Three acceptance criteria were set: MDSC ≥ 0.75, MSHD ≤1mm and TT sparing ≥ 50%.At least 2 criteria had to be met, one of which had to be TT saving, to validate the system.The MDSC was 0.75, MSHD 2.00 mm and the TT saving 55.5% between group A and group B. MDSC among experts was 0.84.Autosegmentation systems in rectal cancer partially met acceptability criteria with the present version.

Four years with FALCON - an ESTRO educational project: achievements and perspectives.

Variability in anatomical contouring is one of the important uncertainties in radiotherapy. FALCON (Fellowship in Anatomic deLineation and CONtouring) is an educational ESTRO (European SocieTy for Radiation and Oncology) project devoted to improve interactive teaching, the homogeneity in contouring and to compare individual contours with endorsed guidelines or expert opinions. This report summarizes the experience from the first 4 years using FALCON for educational activities within ESTRO School and presents the perspectives for the future.

Automatic delineation for replanning in nasopharynx radiotherapy: what is the agreement among experts to be considered as benchmark?

BACKGROUND AND PURPOSE: Anatomic changes during head and neck radiotherapy require replanning. The primary aim of this study is the definition of the agreement among experts in the head and neck automatic delineation frame to use as benchmark. The secondary goal is to assess the reliability of automatic delineation for nasopharynx radiotherapy and time saving. MATERIAL AND METHODS: A computed tomography (CT) scan was acquired in 10 nasopharynx patients along intensity-modulated radiotherapy (IMRT) treatment for replanning. Deformable registration with replanning autocontouring of the structures was performed using VelocityAI 2.3© software defining Structure Set A. The optimization of these contours was obtained through revision by a skilled operator, drawing Structure Set B. An ex novo Structure Set C was segmented on the replanning CT-scan by an expert delineation team. The mean Dice's Similarity Index (mDSI) was calculated between Structure Set A and B, A and C, and between B and C for each volume. All segmentation times for organs at risk (OARs) and clinical target volume (CTV) were recorded and compared. RESULTS: We validated the replanning autocontoured Structure Sets for 10 patients. For volumetric analysis we observed mDSI values of 0.87 for the OARs, 0.70 for nodes, 0.90 for CTV in the Structure Set A-B comparison and respectively of 0.74, 0.63 and 0.78 for the Structure Set A-C one, and 0.78, 0.78 and 0.85 for Structure Set B-C, which represents the existing expert based benchmark. We calculated a mean saved time in Structure Set B of 30 minutes. CONCLUSIONS: Autocontouring procedures offer considerable segmentation time saving with acceptable reliability of the contours, even if an independent check procedure for their optimization is still required to increase their adherence to referential benchmark gold standard among experts, which stands at a 0.80 DSI value.

Is two-dimensional field definition sufficient for pelvic node coverage in rectal cancer compared to technical three-dimensional definition?

BACKGROUND AND AIM: To assess the effectiveness of the potential advantages with 3-dimensional-based treatment planning versus 2-dimensional pelvic bone-based treatment planning in patients with rectal cancer, controlled for clinical stage. METHODS AND MATERIALS: Areas at risk from computed tomography in 30 patients were delineated: mesorectum, presacral, internal iliac, obturator and external iliac nodes. Two planning target volumes per patient were created: PTV_T3 (M + PSN + ON + IIN) and PTV_T4 (M + PSN + ON + IIN + EIN). Two- and 3-dimensional treatment plans for each planning target volume were calculated. Three analyses were performed: 1) mean volume receiving doses >95% and >105%; according to the percentage of prescribed dose to cover at least 95% of the planning target volume, the treatment plan was defined as optimal dose >95%, acceptable dose between 95% and 90%, inferior dose <90%; 2) comparison of the percentage of volume covered by the dose for 2- vs 3-dimensional; 3) determination of the doses at which the lack of volume coverage started to decrease significantly. RESULTS: For PTV_T3, the following was seen: 1) 2D vs 3D comparison showed optimal PTV_T3 coverage in 76.7% and 96.7%, respectively; 2) 2D vs 3D TP coverage difference was significant between 29%-95% of the total dose; 3) the lack of volume coverage started at 30% for 2D and 89% for 3D. For PTV_T4, the following was seen: 1) 2D vs 3D comparison showed an optimal PTV_T4 coverage in 33.3% and 86.7%, respectively; 2) 2D vs 3D TP coverage difference was significant between 7%-97% of the total dose; 3) the lack of volume coverage started at 7% for 2D and 87% for 3D. CONCLUSIONS: The 3D treatment planning was superior to 2D treatment planning in covering areas at risk for pelvic recurrence in patients treated for rectal cancer. The areas with suboptimal coverage may lead to an increased risk of recurrence and should be correlated with the patterns of recurrence.

Clinical validation of atlas-based auto-segmentation of pelvic volumes and normal tissue in rectal tumors using auto-segmentation computed system.

PURPOSE: To evaluate in two different settings - clinical practice and education/training - the reliability, time efficiency and the ideal sequence of an atlas-based auto-segmentation system in pelvic delineation of locally advanced rectal cancer. METHODS: Fourteen consecutive patients were selected between October and December 2011. The images of four were used as an atlas and 10 used for validation. Two independent operators participated: a Delineator to contour and a Reviewer to perform an independent check (IC). The CTV, pelvic subsites and organs at risk were contoured in four different sequences. These included A: manual; B: auto-segmentation; C: auto-segmentation + manual revision; and D: manual + auto-segmentation + manual revision. Contouring was performed by the Delineator using the same planning CT. All of them underwent an IC by a Reviewer. The time required for all the contours were recorded and overlapping evaluation was assessed using a Dice coefficient. RESULTS: In the clinical practice setting there have been 13 minutes time saved between sequences A versus sequences B (from 38 to 25 minutes, p = 0.002), a mean Dice coefficient in favor of sequences A for CTV and all subsites (p = 0.0195). In the educational/training setting there have been 35.2 minutes time saved between sequences C and D 8 (from 73.1 min to 37.9 min, p = 0.002). CONCLUSION: The preliminary data suggest that the use of an atlas-based auto-contouring system may help improve efficiencies in contouring in the clinical practice setting and could have a tutorial role in the educational/training setting.

IGRT in rectal cancer.

To date, no great interest has been shown in the clinical implementation of recent Image-guided radiation therapy (IGRT) modalities in rectal cancer since only a few studies have been published on this issue. This may be explained by the fact that with current treatment modalities locoregional recurrences are already very low (around 10%). However, there is still room for improvement in treatment of high risk patients (cT3 CRM+, cT4, N+). In these patients better results may be obtained improving radiation technique from 2D to 3D, which showed to be more reliable in terms of target coverage. Also, when higher doses are delivered, Intensity Modulated Radiation Therapy (IMRT) may be used to spare small bowel. But before employing 3D irradiation or IMRT, a proper definition of our clinical target volume (CTV) and planning target volume (PTV) is needed. The CTV should encompass the tumour site, the mesorectum and the lateral nodes, recognized as the most likely sites of local recurrence, with different incidence according to tumour stage. Recent studies discussed the correct delineation of these target volumes in respect of tumour site and stage. From the preliminary results of a study conducted in Rome University 2D planning seemed insufficient to cover the different target volumes especially in T4 patients compared to 3D planning. Also an appropriate PTV margin is necessary in order to manage set-up errors and organ motion. Particularly in these patients, the knowledge of mesorectal movement is required to avoid target missing. Large mesorectal displacements were observed in a study carried out in Leuven University in collaboration with Rome University. A systematic review of the literature together with the data from these first experiences led to the awareness that IGRT could help us to follow the target volume and organs at risk during the treatment, allowing adjustments to improve accuracy in dose delivery, especially when dose escalation studies are planned in the treatment of rectal cancer.