Trends in caesarean section rates in Europe from 2015 to 2019 using Robson's Ten Group Classification System: A Euro-Peristat study.

OBJECTIVE: To assess changes in caesarean section (CS) rates in Europe from 2015 to 2019 and utilise the Robson Ten Group Classification System (TGCS) to evaluate the contribution of different obstetric populations to overall CS rates and trends. DESIGN: Observational study utilising routine birth registry data. SETTING: A total of 28 European countries. POPULATION: Births at ≥22 weeks of gestation in 2015 and 2019. METHODS: Using a federated model, individual-level data from routine sources in each country were formatted to a common data model and transformed into anonymised, aggregated data. MAIN OUTCOME MEASURES: By country: overall CS rate. For TGCS groups (by country): CS rate, relative size, relative and absolute contribution to overall CS rate. RESULTS: Among the 28 European countries, both the CS rates (2015, 16.0%-55.9%; 2019, 16.0%-52.2%) and the trends varied (from -3.7% to +4.7%, with decreased rates in nine countries, maintained rates in seven countries (≤ ± 0.2) and with increasing rates in 12 countries). Using the TGCS (for 17 countries), in most countries labour induction increased (groups 2a and 4a), whereas multiple pregnancies (group 8) decreased. In countries with decreasing overall CS rates, CS tended to decrease across all TGCS groups, whereas in countries with increasing rates, CS tended to increase in most groups. In countries with the greatest increase in CS rates (>1%), the absolute contributions of groups 1 (nulliparous term cephalic singletons, spontaneous labour), 2a and 4a (induction of labour), 2b and 4b (prelabour CS) and 10 (preterm cephalic singletons) to the overall CS rate tended to increase. CONCLUSIONS: The TGCS shows varying CS trends and rates among countries of Europe. Comparisons between European countries, particularly those with differing trends, could provide insight into strategies to reduce CS without clinical indication.

Quantifying the burden of stillbirths before 28 weeks of completed gestational age in high-income countries: a population-based study of 19 European countries.

BACKGROUND: International comparisons of stillbirth allow assessment of variations in clinical practice to reduce mortality. Currently, such comparisons include only stillbirths from 28 or more completed weeks of gestational age, which underestimates the true burden of stillbirth. With increased registration of early stillbirths in high-income countries, we assessed the reliability of including stillbirths before 28 completed weeks in such comparisons. METHODS: In this population-based study, we used national cohort data from 19 European countries participating in the Euro-Peristat project on livebirths and stillbirths from 22 completed weeks of gestation in 2004, 2010, and 2015. We excluded countries without national data for stillbirths by gestational age in these periods, or where data available were not comparable between 2004 and 2015. We also excluded those countries with fewer than 10 000 births per year because the proportion of stillbirths at 22 weeks to less than 28 weeks of gestation is small. We calculated pooled stillbirth rates using a random-effects model and changes in rates between 2004 and 2015 using risk ratios (RR) by gestational age and country. FINDINGS: Stillbirths at 22 weeks to less than 28 weeks of gestation accounted for 32% of all stillbirths in 2015. The pooled stillbirth rate at 24 weeks to less than 28 weeks declined from 0·97 to 0·70 per 1000 births from 2004 to 2015, a reduction of 25% (RR 0·75, 95% CI 0·65-0·85). The pooled stillbirth rate at 22 weeks to less than 24 weeks of gestation in 2015 was 0·53 per 1000 births and did not significantly changed over time (RR 0·97, 95% CI 0·80-1·16) although changes varied widely between countries (RRs 0·62-2·09). Wide variation in the percentage of all births occurring at 22 weeks to less than 24 weeks of gestation suggest international differences in ascertainment. INTERPRETATION: Present definitions used for international comparisons exclude a third of stillbirths. International consistency of reporting stillbirths at 24 weeks to less than 28 weeks suggests these deaths should be included in routinely reported comparisons. This addition would have a major impact, acknowledging the burden of perinatal death to families, and making international assessments more informative for clinical practice and policy. Ascertainment of fetal deaths at 22 weeks to less than 24 weeks should be stabilised so that all stillbirths from 22 completed weeks of gestation onwards can be reliably compared. FUNDING: EU Union under the framework of the Health Programme and the Bridge Health Project.

Is induction of labor a reasonable option for breech presentation?

INTRODUCTION: Whereas spontaneous onset of labor and vaginal delivery for breech presentation is considered to be a safe and effective option in selected cases, the safety of induction of labor is not established yet. The objectives of this study were to describe the outcomes of pregnancy in women induced with a fetus in breech presentation and compare the outcomes with those undergoing planned cesarean delivery. MATERIAL AND METHODS: We performed a secondary analysis of the observational prospective multicenter PREMODA study, including all singleton breech deliveries after 37 weeks in 174 centers in France and Belgium. We excluded women with spontaneous onset of labor, scarred uterus or intrauterine fetal death. Our study population consisted of women with either induction of labor or planned cesarean delivery. The primary outcome was the composite criteria of neonatal mortality and serious morbidity used in the Term Breech Trial and in the PREMODA prospective cohort. RESULTS: Our study population consisted of 4138 women, 218 with induction of labor and 3920 with planned cesarean. Two-thirds (67.4%) of the women in the induction of labor group delivered vaginally. There was no significant difference between the groups for the primary outcome (48 [1.2%] in the planned cesarean group vs 3 [1.4%] in the induction of labor group, P = 0.75). Moreover, none of the criteria of the composite primary outcome was significantly more frequent in the induction of labor group. CONCLUSIONS: Induction of labor for breech presentation does not seem to increase neonatal mortality or severe neonatal morbidity compared with planned cesarean delivery.

Evaluation of the self-sampling for cervical cancer screening in Bolivia.

BACKGROUND: Incidence and mortality rates of cervical cancer in Bolivia are the highest in Latin America. Vaginal cell self-sampling can improve screening coverage. Information on common reasons for low screening coverage and preferences for future screening are essential to reduce cervical cancer incidence. We aimed to evaluate the knowledge about human papillomavirus (HPV) and cervical cancer of Bolivian women from urban, peri-urban and rural areas of Cochabamba and to determine their degree of acceptability and confidence towards vaginal HPV self-sampling. In addition, we assessed the impact of self-sampling on cervical cancer screening coverage in a selected peri-urban area. METHODS: We gathered information from women living in urban, peri-urban and rural areas of Cochabamba province in Bolivia using two different structured questionnaires. In Survey1, we collected information from 222 women about their knowledge on HPV and cervical cancer. In Survey 2, the acceptance and confidence towards vaginal HPV self-sampling compared to the physician-sampling was assessed in 221 women. A non-probabilistic stratified sampling by areas was carried out for the two questionnaires. In the third phase of the study, we determined the impact of HPV self-sampling collection on screening coverage in a peri-urban area of Cochabamba. RESULTS: Bolivian women knew little or nothing about cervical cancer and HPV infection in all areas. They all found self-sampling collection easier to perform (86.9 to 93.2%) and more comfortable (79.4 to 83.3%) compared to physician sampling. Sampling accuracy to detect cervical cancer was probably higher in their point of view when it was taken by physician (35.1 to 63.5%). However in rural areas women preferred self-sampling. Accordingly, the campaign of vaginal HPV self-sampling in this peri-urban area increased screening coverage, reaching in three months the annual rate average. CONCLUSIONS: The knowledge about cervical cancer and HPV infection is poor in Bolivia. Despite greater acceptance of the vaginal HPV self-sampling in all areas, women kept greater confidence in the screening performed by the gynecologist although HPV self-sampling improved coverage rate.

Contraception determinants in youths of Sierra Leone are largely behavioral.

BACKGROUND: Sexual initiation occurs early in Sierra Leone. This study aims to analyze the determinants of condom and/or contraceptive use among a representative sample of young persons (10 to 24 years) in Sierra Leone. METHODS: This is a secondary analysis of data from a study conducted to monitor the implementation of a UNFPA package of interventions directed to improve SRH in young people of Sierra Leone. This assessment was conducted in 2016 at the end of the Ebola outbreak. In consequence, determinants linked to healthy lifestyle behaviors and UNFPA interventions were explored in addition to the usual determinants: socio demographic and sexual lifestyle. This study is a household quantitative survey with open ended questions used to illustrate and complete the analysis. RESULTS: A total of 1409 young people were interviewed: of these, 216 boys and 381 girls were sexually active. Those who were pregnant or wished for pregnancy were excluded, leaving 194 boys and 268 girls for the analysis of determinants. The proportion of young people using neither condom nor other contraception at their last sexual intercourse in the whole sample was 40.5% and there was no statistically significant difference between boys and girls (42.3 vs 39.2; P = 0.504). Determinants were assessed and, after multivariable analysis, results differed between boys and girls and showed the importance of behavioral aspects. Four determinants were common to boys and girls: literacy, distance, negotiation capacity and hand washing. However, the distance factor for girls was to the health facility and for boys it was to school. Three more determinants remained in the boy's model: sleeping under a bednet, number of sexual partners and knowledge of contraceptive methods. Opinions about condoms and contraception revealed important barriers; opposition to contraceptive use was the main reason for non-use for both boys and girls, while lack of access was an important reason for boys. CONCLUSION: There is a need to reach out to the 40% of young people who are sexually active and neither pregnant nor with pregnancy desire, and are not using condom or contraception.

Are all immigrant mothers really at risk of low birth weight and perinatal mortality? The crucial role of socio-economic status.

BACKGROUND: Increasing studies show that immigrants have different perinatal health outcomes compared to native women. Nevertheless, we lack a systematic examination of the combined effects of immigrant status and socioeconomic factors on perinatal outcomes. Our objectives were to analyse national Belgian data to determine 1) whether socioeconomic status (SES) modifies the association between maternal nationality and perinatal outcomes (low birth weight and perinatal mortality); 2) the effect of adopting the Belgian nationality on the association between maternal foreign nationality and perinatal outcomes. METHODS: This study is a population-based study using the data from linked birth and death certificates from the Belgian civil registration system. Data are related to all singleton births to mothers living in Belgium between 1998 and 2010. Perinatal mortality and low birth weight (LBW) were estimated by SES (maternal education and parental employment status) and by maternal nationality (at her own birth and at her child's birth). We used logistic regression to estimate the odds ratios for the associations between nationality and perinatal outcomes after adjusting for and stratifying by SES. RESULTS: The present study includes, for the first time, all births in Belgium; that is 1,363,621 singleton births between 1998 and 2010. Compared to Belgians, we observed an increased risk of perinatal mortality in all migrant groups (p < 0.0001), despite lower rates of LBW in some nationalities. Immigrant mothers with the Belgian nationality had similar rates of perinatal mortality to women of Belgian origin and maintained their protection against LBW (p < 0.0001). After adjustment, the excess risk of perinatal mortality among immigrant groups was mostly explained by maternal education; whereas for sub-Saharan African mothers, mortality was mainly affected by parental employment status. After stratification by SES, we have uncovered a significant protective effect of immigration against LBW and perinatal mortality for women with low SES but not for high SES. CONCLUSIONS: Our results show a protective effect of migration in relation to perinatal mortality and LBW among women of low SES. Hence, the study underlines the importance of taking into account socioeconomic status in order to understand more fully the relationship between migration and perinatal outcomes. Further studies are needed to analyse more finely the impact of socio-economic characteristics on perinatal outcomes.

Variations in rates of severe perineal tears and episiotomies in 20 European countries: a study based on routine national data in Euro-Peristat Project.

INTRODUCTION: Rates of severe perineal tears and episiotomies are indicators of obstetrical quality of care, but their use for international comparisons is complicated by difficulties with accurate ascertainment of tears and uncertainties regarding the optimal rate of episiotomies. We compared rates of severe perineal tears and episiotomies in European countries and analysed the association between these two indicators. MATERIAL AND METHODS: We used aggregate data from national routine statistics available in the Euro-Peristat project. We compared rates of severe (third- and fourth-degree) tears and episiotomies in 2010 by mode of vaginal delivery (n = 20 countries), and investigated time trends between 2004 and 2010 (n = 9 countries). Statistical associations were assessed with Spearman's ranked correlations (rho). RESULTS: In 2010 in all vaginal deliveries, rates of severe tears ranged from 0.1% in Romania to 4.9% in Iceland, and rates of episiotomies from 3.7% in Denmark to 75.0% in Cyprus. A negative correlation between the rates of episiotomies and severe tears was observed in all deliveries (rho = -0.66; p = 0.001), instrumental deliveries (rho = -0.67; p = 0.002) and non-instrumental deliveries (rho = -0.72; p < 0.001). However there was no relation between time trends of these two indicators (rho = 0.43; p = 0.28). CONCLUSIONS: The large variations in severe tears and episiotomies and the negative association between these indicators in 2010 show the importance of improving the assessment and reporting of tears in each country, and evaluating the impact of low episiotomy rates on the perineum.

Socioeconomic inequalities in stillbirth rates in Europe: measuring the gap using routine data from the Euro-Peristat Project.

BACKGROUND: Previous studies have shown that socioeconomic position is inversely associated with stillbirth risk, but the impact on national rates in Europe is not known. We aimed to assess the magnitude of social inequalities in stillbirth rates in European countries using indicators generated from routine monitoring systems. METHODS: Aggregated data on the number of stillbirths and live births for the year 2010 were collected for three socioeconomic indicators (mothers' educational level, mothers' and fathers' occupational group) from 29 European countries participating in the Euro-Peristat project. Educational categories were coded using the International Standard Classification of Education (ISCED) and analysed as: primary/lower secondary, upper secondary and postsecondary. Parents' occupations were grouped using International Standard Classification of Occupations (ISCO-08) major groups and then coded into 4 categories: No occupation or student, Skilled/ unskilled workers, Technicians/clerical/service occupations and Managers/professionals. We calculated risk ratios (RR) for stillbirth by each occupational group as well as the percentage population attributable risks using the most advantaged category as the reference (post-secondary education and professional/managerial occupations). RESULTS: Data on stillbirth rates by mothers' education were available in 19 countries and by mothers' and fathers' occupations in 13 countries. In countries with these data, the median RR of stillbirth for women with primary and lower secondary education compared to women with postsecondary education was 1.9 (interquartile range (IQR): 1.5 to 2.4) and 1.4 (IQR: 1.2 to 1.6), respectively. For mothers' occupations, the median RR comparing outcomes among manual workers with managers and professionals was 1.6 (IQR: 1.0-2.1) whereas for fathers' occupations, the median RR was 1.4 (IQR: 1.2-1.8). When applied to the entire set of countries with data about mothers' education, 1606 out of 6337 stillbirths (25 %) would not have occurred if stillbirth rates for all women were the same as for women with post-secondary education in their country. CONCLUSIONS: Data on stillbirths and socioeconomic status from routine systems showed widespread and consistent socioeconomic inequalities in stillbirth rates in Europe. Further research is needed to better understand differences between countries in the magnitude of the socioeconomic gradient.

Potential avoidability of planned cesarean sections in a French national database.

OBJECTIVE: To study the frequency and determinants of potentially avoidable planned cesarean sections, with a classification based on their indications, maternal obstetric history, and information about the current pregnancy. DESIGN: Cross-sectional population-based study. SETTING: All maternity units in France (n = 535). POPULATION: A total of 14,681 women from the 2010 French National Perinatal Survey, a routine survey of a representative sample of births. METHODS: Planned cesareans were classified in two groups: potentially avoidable and unavoidable. The classification was based on the French national guidelines and used data from medical records. We used logistic regression analyses to compare characteristics of the mothers with potentially avoidable cesareans with those of women who had a trial of labor. Analyses were performed separately in primiparas and multiparas. MAIN OUTCOME MEASURE: Rate of potentially avoidable planned cesarean sections. RESULTS: The overall planned cesarean rate was 10.9%; 28% of these cesareans were found to be potentially avoidable. Breech presentation and history of one previous cesarean accounted for 83% of them. Determinants of potential avoidability were maternal age >35 years, intensive surveillance during pregnancy, and private status of the unit [adjusted odds ratio (OR) 1.9, 95% CI 1.2-3.2 among primiparas; adjusted OR 2.5, 95% CI 1.5-4.3 among multiparas]. Obesity was also a significant determinant but only among multiparas (adjusted OR 2.7, 95% CI 1.9-3.8). No association was found with maternal social characteristics. CONCLUSION: Our results suggest a high proportion of potentially avoidable cesareans and highlight the associated obstetric situations. They can help to target policies aimed at reducing cesarean rates.

European Board and College of Obstetrics and Gynaecology position statement on maternal mortality surveillance in Europe.

Maternal mortality data and review are important indicators of the effectiveness of maternity healthcare systems and an impetus for action. Recently, a rising incidence of maternal mortality in high income countries has been reported. Various publications have raised concern about data collection methods at country level, as this usually relies mainly on national vital statistics. It is therefore essential that the collected data are complete and accurate and conform to international definitions and disease classification. Accurate data and review can only be truly available when an Enhanced Obstetric Surveillance System is in place. EBCOG calls for action by national societies to work closely with their respective ministries of health to ensure that high quality surveillance systems are in place.

Stereotactic Body Radiotherapy (SBRT) to Localised Prostate Cancer in the Era of MRI-Guided Adaptive Radiotherapy: Doses Delivered in the HERMES Trial Comparing Two- and Five-Fraction Treatments.

HERMES is a phase II trial of MRI-guided daily-adaptive radiotherapy (MRIgART) randomising men with localised prostate cancer to either 2-fractions of SBRT with a boost to the tumour or 5-fraction SBRT. In the context of this highly innovative regime the dose delivered must be carefully considered. The first ten patients recruited to HERMES were analysed in order to establish the dose received by the targets and organs at risk (OARS) in the context of intrafraction motion. A regression analysis was performed to measure how the volume of air within the rectum might further impact rectal dose secondary to the electron return effect (ERE). One hundred percent of CTV target objectives were achieved on the MRI taken prior to beam-on-time. The post-delivery MRI showed that high-dose CTV coverage was achieved in 90% of sub-fractions (each fraction is delivered in two sub-fractions) in the 2-fraction cohort and in 88% of fractions the 5-fraction cohort. Rectal D1 cm3 was the most exceeded constraint; three patients exceeded the D1 cm3 < 20.8 Gy in the 2-fraction cohort and one patient exceeded the D1 cm3 < 36 Gy in the 5-fraction cohort. The volume of rectal gas within 1 cm of the prostate was directly proportional to the increase in rectal D1 cm3, with a strong (R = 0.69) and very strong (R = 0.90) correlation in the 2-fraction and 5-fraction cohort respectively. Dose delivery specified in HERMES is feasible, although for some patients delivered doses to both target and OARs may vary from those planned.

Magnetic resonance image-guided adaptive radiotherapy enables safe CTV-to-PTV margin reduction in prostate cancer: a cine MRI motion study.

Introduction: We aimed to establish if stereotactic body radiotherapy to the prostate can be delivered safely using reduced clinical target volume (CTV) to planning target volume (PTV) margins on the 1.5T MR-Linac (MRL) (Elekta, Stockholm, Sweden), in the absence of gating. Methods: Cine images taken in 3 orthogonal planes during the delivery of prostate SBRT with 36.25 Gray (Gy) in 5 fractions on the MRL were analysed. Using the data from 20 patients, the percentage of radiotherapy (RT) delivery time where the prostate position moved beyond 1, 2, 3, 4 and 5 mm in the left-right (LR), superior-inferior (SI), anterior-posterior (AP) and any direction was calculated. Results: The prostate moved less than 3 mm in any direction for 90% of the monitoring period in 95% of patients. On a per-fraction basis, 93% of fractions displayed motion in all directions within 3 mm for 90% of the fraction delivery time. Recurring motion patterns were observed showing that the prostate moved with shallow drift (most common), transient excursions and persistent excursions during treatment. Conclusion: A 3 mm CTV-PTV margin is safe to use for the treatment of 5 fraction prostate SBRT on the MRL, without gating. In the context of gating this work suggests that treatment time will not be extensively lengthened when an appropriate gating window is applied.

Interim Toxicity Analysis From the Randomized HERMES Trial of 2- and 5-Fraction Magnetic Resonance Imaging-Guided Adaptive Prostate Radiation Therapy.

PURPOSE: Ultrahypofractionated radiation therapy (UHRT) is an effective treatment for localized prostate cancer with an acceptable toxicity profile; boosting the visible intraprostatic tumor has been shown to improve biochemical disease-free survival with no significant effect on genitourinary (GU) and gastrointestinal (GI) toxicity. METHODS AND MATERIALS: HERMES is a single-center noncomparative randomized phase 2 trial in men with intermediate or lower high risk prostate cancer. Patients were allocated (1:1) to 36.25 Gy in 5 fractions over 2 weeks or 24 Gy in 2 fractions over 8 days with an integrated boost to the magnetic resonance imaging (MRI) visible tumor of 27 Gy in 2 fractions. A minimization algorithm with a random element with risk group as a balancing factor was used for participant randomization. Treatment was delivered on the Unity MR-Linac (Elekta AB) with daily online adaption. The primary endpoint was acute GU Common Terminology Criteria for Adverse Events version 5.0 toxicity with the aim of excluding a doubling of the rate of acute grade 2+ GU toxicity seen in PACE. Analysis was by treatment received and included all participants who received at least 1 fraction of study treatment. This interim analysis was prespecified (stage 1 of a 2-stage Simon design) for when 10 participants in each treatment group had completed the acute toxicity monitoring period (12 weeks after radiation therapy). RESULTS: Acute grade 2 GU toxicity was reported in 1 (10%) patient in the 5-fraction group and 2 (20%) patients in the 2-fraction group. No grade 3+ GU toxicities were reported. CONCLUSIONS: At this interim analysis, the rate of GU toxicity in the 2-fraction and 5-fraction treatment groups was found to be below the prespecified threshold (5/10 grade 2+) and continuation of the study to complete recruitment of 23 participants per group was recommended.

Measurement and Incorporation of Laryngeal Motion Using cine-MRI on an MR-Linear Accelerator to Generate Radiation Therapy Plans for Early-stage Squamous Cell Cancers of the Glottis.

Purpose: Swallow-related motion of the larynx is most significant in the cranio-caudal directions and of` short duration. Conventional target definition for radical radiation therapy includes coverage of the whole larynx. This study longitudinally examined respiration- and swallow-related laryngeal motions using cine-magnetic resonance imaging. We further analyzed the dosimetry to organs at risk by comparing 3D-conformal radiation therapy (3D-CRT), volumetric modulated arc therapy (VMAT), and intensity modulated radiation therapy (IMRT) techniques. Methods: Fifteen patients with T1-2 N0 glottic squamous cell carcinomas were prospectively recruited for up to 3 cine-MRI scans on the Elekta Unity MR-Linear accelerator, at the beginning, middle, and end of a course of radical radiation therapy. Swallow frequency and motion of the hyoid bone, cricoid and thyroid cartilages, and vocal cords were recorded during swallow and rest. Adapted treatment volumes consisted of gross tumor volume + 0.5-1 cm to a clinical target volume with an additional internal target volume (ITV) for personalized resting-motion. Swallow-related motion was deemed infrequent and was not accounted for in the ITV. We compared radiation therapy plans for 3D-CRT (whole larynx), VMAT (whole larynx), and VMAT and IMRT (ITV for resting motion). Results: Resting- and swallow-related motions were most prominent in the cranio-caudal plane. There were no significant changes in the magnitude of motion over the course of radiation therapy. There was a trend of a progressive reduction in the frequency of swallow. Treatment of partial larynx volumes with intensity modulated methods significantly reduced the dose to carotid arteries, compared with treatment of whole larynx volumes. Robustness analysis demonstrated that when accounting for intrafraction swallow, the total dose delivered to the ITV/planning target volume was maintained at above 95%. Conclusions: Swallow-related motions are infrequent and accounting for resting motion in an ITV is sufficient. VMAT/IMRT techniques that treat more conformal targets can significantly spare critical organs at risk such as the carotid arteries and thyroid gland, potentially reducing the risk of carotid artery stenosis-related complications and other long-term complications.

The Radiation Therapist profession through the lens of new technology: A practice development paper based on the ESTRO Radiation Therapist Workshops.

Technological advances in radiation therapy impact on the role and scope of practice of the radiation therapist. The European Society of Radiotherapy and Oncology (ESTRO) recently held two workshops on this topic and this position paper reflects the outcome of this workshop, which included radiation therapists from all global regions. Workflows, quality assurance, research, IGRT and ART as well as clinical decision making are the areas of radiation therapist practice that will be highly influenced by advancing technology in the near future. This position paper captures the opportunities that this will bring to the radiation therapist profession, to the practice of radiation therapy and ultimately to patient care.

Carpe Diem: Making the Most of Plan-of-the-Day for Cervical Cancer Radiation Therapy.

PURPOSE: Radiation therapy is the key treatment for locally advanced cervical cancer. Organ motion presents a challenge to accurate targeting of external beam radiation therapy. The plan-of-the-day (PotD) adaptive approach is therefore an attractive option. We present our experience and the procedural steps required to implement PotD for cervix cancer. METHODS AND MATERIALS: We reviewed relevant studies on organ motion and adaptive radiation therapy identified through a literature search and cross referencing. These included 10 dosimetric and 3 quality of life studies directly assessing the PotD approach to radiation therapy in cervix cancer. RESULTS: Studies show improvements in target coverage and reduction of dose received by normal tissues and suggest improved toxicity. Clinical implementation of PotD has been slow because of a number of difficulties and uncertainties, which we discuss with the aim of helping teams to implement PotD at their center. CONCLUSIONS: The PotD approach improves dosimetry and may improve toxicity. We describe a framework to assist with practical implementation.

Prostate stereotactic body radiotherapy: quantifying intra-fraction motion and calculating margins using the new BIR geometric uncertainties in daily online IGRT recommendations.

OBJECTIVES: To measure the magnitude of intra-fraction prostate motion (IFPM) during stereotactic radiotherapy (SBRT) delivered without intra-fraction tracking.To assess if current margins adequately cover IFPM.To derive margins using new guidelines. METHODS: IFPM was determined in 20 patients receiving 36.25 Gy in 5 fractions using 97 pairs of pre- and post-treatment cone beam CT (CBCT) scans. Correlation of time between CBCT acquisitions and motion was determined. The magnitude of IFPM was compared to current margins (6 mm isotropic, 3 mm posterior). Margins were calculated using IFPM alone and updated guidelines. RESULTS: The averaged 3D root mean square IFPM was 2.5 mm (4.2 mm). Independent prostate motion was predominantly posterior (70%) and inferior (63%). There was weak correlation between posterior (ρ = 0.38) and inferior (ρ = 0.36) IFPM and time. IFPM greater than current margins occurred in 8 of 97 fractions, six in the posterior direction. Margins were ≤3.5 mm using IFPM alone and ≤3.3 mm Left 3.5 mm Right, 7.0 mm inferior, 3.7 mm superior, 4.4 mm anterior and 3.3 mm posterior using new guidelines, compensating for motion in 92% of fractions. CONCLUSIONS: Our current SBRT margins account for 92% of IFPM, predominantly posterior and inferior. Although updated guidelines suggest an increase in margins inferiorly, any increase must be balanced against the possibility of increased toxicity, particularly if biochemical control and side-effects are favourable with current practice. ADVANCES IN KNOWLEDGE: The difference between current clinical margins and those determined using updated guidance is demonstrated. The implications must be considered against clinical outcomes.

Evaluation of non-vendor magnetic resonance imaging sequences for use in bladder cancer magnetic resonance image guided radiotherapy.

Hybrid systems that combine Magnetic Resonance Imaging (MRI) and linear accelerators are available clinically to guide and adapt radiotherapy. Vendor-approved MRI sequences are provided, however alternative sequences may offer advantages. The aim of this study was to develop a systematic approach for non-vendor sequence evaluation, to determine safety, accuracy and overall clinical application of two potential sequences for bladder cancer MRI guided radiotherapy. Non-vendor sequences underwent and passed clinical image qualitative review, phantom quality assurance, and radiotherapy planning assessments. Volunteer workflow tests showed the potential for one sequence to reduce workflow time by 27% compared to the standard vendor sequence.

Evaluation of therapeutic radiographer contouring for magnetic resonance image guided online adaptive prostate radiotherapy.

BACKGROUND AND PURPOSE: The implementation of MRI-guided online adaptive radiotherapy has facilitated the extension of therapeutic radiographers' roles to include contouring, thus releasing the clinician from attending daily treatment. Following undergoing a specifically designed training programme, an online interobserver variability study was performed. MATERIALS AND METHODS: 117 images from six patients treated on a MR Linac were contoured online by either radiographer or clinician and the same images contoured offline by the alternate profession. Dice similarity coefficient (DSC), mean distance to agreement (MDA), Hausdorff distance (HD) and volume metrics were used to analyse contours. Additionally, the online radiographer contours and optimised plans (n = 59) were analysed using the offline clinician defined contours. After clinical implementation of radiographer contouring, target volume comparison and dose analysis was performed on 20 contours from five patients. RESULTS: Comparison of the radiographers' and clinicians' contours resulted in a median (range) DSC of 0.92 (0.86 - 0.99), median (range) MDA of 0.98 mm (0.2-1.7) and median (range) HD of 6.3 mm (2.5-11.5) for all 117 fractions. There was no significant difference in volume size between the two groups. Of the 59 plans created with radiographer online contours and overlaid with clinicians' offline contours, 39 met mandatory dose constraints and 12 were acceptable because 95 % of the high dose PTV was covered by 95 % dose, or the high dose PTV was within 3 % of online plan. A clinician blindly reviewed the eight remaining fractions and, using trial quality assurance metrics, deemed all to be acceptable. Following clinical implementation of radiographer contouring, the median (range) DSC of CTV was 0.93 (0.88-1.0), median (range) MDA was 0.8 mm (0.04-1.18) and HD was 5.15 mm (2.09-8.54) respectively. Of the 20 plans created using radiographer online contours overlaid with clinicians' offline contours, 18 met the dosimetric success criteria, the remaining 2 were deemed acceptable by a clinician. CONCLUSION: Radiographer and clinician prostate and seminal vesicle contours on MRI for an online adaptive workflow are comparable and produce clinically acceptable plans. Radiographer contouring for prostate treatment on a MR-linac can be effectively introduced with appropriate training and evaluation. A DSC threshold for target structures could be implemented to streamline future training.

Interobserver variation of clinical oncologists compared to therapeutic radiographers (RTT) prostate contours on T2 weighted MRI.

The implementation of MRI-guided online adaptive radiotherapy has enabled extension of therapeutic radiographers' roles to include contouring. An offline interobserver variability study compared five radiographers' and five clinicians' contours on 10 MRIs acquired on a MR-Linac from 10 patients. All contours were compared to a "gold standard" created from an average of clinicians' contours. The median (range) DSC of radiographers' and clinicians' contours compared to the "gold standard" was 0.91 (0.86-0.96), and 0.93 (0.88-0.97) respectively illustrating non-inferiority of the radiographers' contours to the clinicians. There was no significant difference in HD, MDA or volume size between the groups.