Research-ready data: the C-Surv data model

Research-ready data (data curated to a defined standard) increase scientific opportunity and rigour by integrating the data environment. The development of research platforms has highlighted the value of research-ready data, particularly for multi-cohort analyses. Following stakeholder consultation, a standard data model (C-Surv) optimised for data discovery, was developed using data from 5 population and clinical cohort studies. The model uses a four-tier nested structure based on 18 data themes selected according to user behaviour or technology. Standard variable naming conventions are applied to uniquely identify variables within the context of longitudinal studies. The data model was used to develop a harmonised dataset for 11 cohorts. This dataset populated the Cohort Explorer data discovery tool for assessing the feasibility of an analysis prior to making a data access request. Data preparation times were compared between cohort specific data models and C-Surv.It was concluded that adopting a common data model as a data standard for the discovery and analysis of research cohort data offers multiple benefits.

Effect of a test-and-treat approach to vitamin D supplementation on risk of all cause acute respiratory tract infection and covid-19: phase 3 randomised controlled trial (CORONAVIT)

OBJECTIVE

To determine the effect of population level implementation of a test-and-treat approach to correction of suboptimal vitamin D status (25-hydroxyvitamin D (25(OH)D) <75 nmol/L) on risk of all cause acute respiratory tract infection and covid 19.

DESIGN

Phase 3 open label randomised controlled trial.

SETTING

United Kingdom.

PARTICIPANTS

6200 people aged ≥16 years who were not taking vitamin D supplements at baseline.

INTERVENTIONS

Offer of a postal finger prick test of blood 25(OH)D concentration with provision of a six month supply of lower dose vitamin D (800 IU/day, n=1550) or higher dose vitamin D (3200 IU/day, n=1550) to those with blood 25(OH)D concentration <75 nmol/L, compared with no offer of testing or supplementation (n=3100). Follow-up was for six months.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of participants with at least one swab test or doctor confirmed acute respiratory tract infection of any cause. A secondary outcome was the proportion of participants with swab test confirmed covid-19. Logistic regression was used to calculate odds ratios and associated 95% confidence intervals. The primary analysis was conducted by intention to treat.

RESULTS

Of 3100 participants offered a vitamin D test, 2958 (95.4%) accepted and 2674 (86.3%) had 25(OH)D concentrations <75 nmol/L and received vitamin D supplements (n=1328 lower dose, n=1346 higher dose). Compared with 136/2949 (4.6%) participants in the no offer group, at least one acute respiratory tract infection of any cause occurred in 87/1515 (5.7%) in the lower dose group (odds ratio 1.26, 95% confidence interval 0.96 to 1.66) and 76/1515 (5.0%) in the higher dose group (1.09, 0.82 to 1.46). Compared with 78/2949 (2.6%) participants in the no offer group, 55/1515 (3.6%) developed covid-19 in the lower dose group (1.39, 0.98 to 1.97) and 45/1515 (3.0%) in the higher dose group (1.13, 0.78 to 1.63).

CONCLUSIONS

Among people aged 16 years and older with a high baseline prevalence of suboptimal vitamin D status, implementation of a population level test-and-treat approach to vitamin D supplementation was not associated with a reduction in risk of all cause acute respiratory tract infection or covid-19.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04579640.

The Dementias Platform UK (DPUK) Data Portal

The Dementias Platform UK Data Portal is a data repository facilitating access to data for 3 370 929 individuals in 42 cohorts. The Data Portal is an end-to-end data management solution providing a secure, fully auditable, remote access environment for the analysis of cohort data. All projects utilising the data are by default collaborations with the cohort research teams generating the data. The Data Portal uses UK Secure eResearch Platform infrastructure to provide three core utilities: data discovery, access, and analysis. These are delivered using a 7 layered architecture comprising: data ingestion, data curation, platform interoperability, data discovery, access brokerage, data analysis and knowledge preservation. Automated, streamlined, and standardised procedures reduce the administrative burden for all stakeholders, particularly for requests involving multiple independent datasets, where a single request may be forwarded to multiple data controllers. Researchers are provided with their own secure 'lab' using VMware which is accessed using two factor authentication. Over the last 2 years, 160 project proposals involving 579 individual cohort data access requests were received. These were received from 268 applicants spanning 72 institutions (56 academic, 13 commercial, 3 government) in 16 countries with 84 requests involving multiple cohorts. Projects are varied including multi-modal, machine learning, and Mendelian randomisation analyses. Data access is usually free at point of use although a small number of cohorts require a data access fee.

The Secure Anonymised Information Linkage databank Dementia e-cohort (SAIL-DeC)

Introduction

The rising burden of dementia is a global concern, and there is a need to study its causes, natural history and outcomes. The Secure Anonymised Information Linkage (SAIL) Databank contains anonymised, routinely-collected healthcare data for the population of Wales, UK. It has potential to be a valuable resource for dementia research owing to its size, long follow-up time and prospective collection of data during clinical care.

Objectives

We aimed to apply reproducible methods to create the SAIL dementia e-cohort (SAIL-DeC). We created SAIL-DeC with a view to maximising its utility for a broad range of research questions whilst minimising duplication of effort for researchers.

Methods

SAIL contains individual-level, linked primary care, hospital admission, mortality and demographic data. Data are currently available until 2018 and future updates will extend participant follow-up time. We included participants who were born between 1st January 1900 and 1st January 1958 and for whom primary care data were available. We applied algorithms consisting of International Classification of Diseases (versions 9 and 10) and Read (version 2) codes to identify participants with and without all-cause dementia and dementia subtypes. We also created derived variables for comorbidities and risk factors.

Results

From 4.4 million unique participants in SAIL, 1.2 million met the cohort inclusion criteria, resulting in 18.8 million person-years of follow-up. Of these, 129,650 (10%) developed all-cause dementia, with 77,978 (60%) having dementia subtype codes. Alzheimer's disease was the most common subtype diagnosis (62%). Among the dementia cases, the median duration of observation time was 14 years.

Conclusion

We have created a generalisable, national dementia e-cohort, aimed at facilitating epidemiological dementia research.

A United Kingdom Multicenter Study of Icodextrin in Continuous Ambulatory Peritoneal Dialysis

While glucose remains the only osmotic agent used universally for peritoneal dialysis, its various shortcomings for the long dwell equilibration continuous ambulatory peritoneal dialysis (CAPD) has led to a search for alternative agents. The large molecular weight group has been of interest, because these agents theoretically would lead to greater ultrafiltration and a better metabolic profile. Mostsubstances (dextrans, charged macromolecules) have been found unsuitable for reasons of insolubility, allergenicity, and peritoneal toxicity. Short-chain polypeptides have been studied in humans, but the experience is limited, and there is the potential for allergenicity with long-term use.

The only large molecular weight agent that has been studied in some detail but hitherto in one center only and in a limited number of patients is glucose polymer (generic name, icodextrin). Because of the promise shown by these initial studies, a randomized controlled multicenter investigation of icodextrin in CAPD (MIDAS Study Group) was undertaken to evaluate the long-term safety and efficacy by comparing daily overnight (8 12 hours) use of a slightly hypo-osmolar solution (282 mOsm/ kg) with 1.36% (346 mOsm/kg) and 3.86% (484 mOsm/kg) glucose exchanges. Over a 6-month period 209 patients from 11 centers in the United Kingdom were randomized, with 106 allocated to receive icodextrin (study group) and 103 to remain on glucose (control group). One hundred and thirty-eight patients completed the 6-month study (71 control, 67 study).

The mean net ultrafiltration overnight with icodextrin was 3.5 times greater than 1.36% at 8 hours and 5.5 times greater at 12 hours (p<0.0001), but no different from that of 3.86% glucose at 8 and 12 hours (although for the latter dwell the net mean ultrafiltration volume was greater by about 140 mL). Biochemical profiles were no different except for a small fall in serum sodium and chloride in the icodextrin group. The mean serum maltose rose to a steady-state level of 1.2 g/L within 2 weeks and remained stable. The mean carbohydrate absorbed for icodextrin (29±5 g) was lower than with 3.86% glucose (62±5 g). The use of icodextrin did not increase the incidence of peritonitis, nor did it alter its outcome, affect uptake of icodextrin from the peritoneum, alter serum osmolality or sodium levels. There were no adverse effects associated with the use of icodextrin, and the overall CAPD-related symptom score was significantly better for icodextrin than control subjects.

This study and subsequent extensive use and clinical experience has demonstrated that the daily use of an iso-osmolar icodextrin solution is generally well tolerated, effective, and could replace the overnight use of hyperosmotic glucose solution. Its use was of equal efficacy in peritonitis and in diabetic patients. The elevated levels of maltose did not appear to have any clinical side effects.

Peritonitis Occurrence in a Multicenter Study of Icodextrin and Glucose in Capd

Objective

To compare peritonitis occurrence and outcome in a large U.K. study Multicentre Investigation of Icodextrin in Ambulatory Dialysis (MIDAS).

Design

Prospective, randomized, controlled 6-month comparison of icodextrin with glucose for the long dwell in continuous ambulatory peritoneal dialysis (CAPD) patients.

Setting

Eleven CAPD units in U.K. teaching hospitals.

Patients

A total of 209 patients established on CAPD for at least 3 months (103 control, 106 icodextrin). Twentythree control (C) and 22 icodextrin (I) patients experienced peritonitis during the study.

Intervention

Patients who had peritonitis remained on treatment (unless CAPD was withdrawn, temporarily or permanently).

Main Outcome Measures

The main outcome measures were the rate of peritonitis and duration of CAPD treatment prestudy; the rate of peritonitis episodes and their outcome during study; the effect of peritonitis on laboratory variables, serum icodextrin metabolites, and ultrafiltration efficacy.

Results

Prestudy: Nine (39%) of C but 14 (64%) of I patients had suffered previous peritonitis episode(s), with overall rates of 0.58 and 0.78 episodes per patientyear, respectively.

During study

There were 31 C episodes and 35 I episodes, with overall rates of 0.76 and 0.93 per patientyear, respectively. The increase in the C and I groups was 31% and 19%, respectively. Serum osmolality and sodium levels were unaffected by peritonitis, and there was no increase in serum icodextrin metabolites during peritonitis. Overnight ultrafiltration volume during peritonitis (mean±SD) declined slightly from 218±354 mL to 185±299 mL (NS) in the control group, but increased in the icodextrin group from 570±146 mL to 723±218 mL (p < 0.01).

Conclusions

Using icodextrin for the long dwell in CAPD does not increase the rate of peritonitis, nor does it alter the outcome of peritonitis. Peritonitis does not affect uptake of icodextrin from the peritoneum.

Data Services for Cohort Studies: Increasing the impact of existing research studies and epidemiological readiness

IntroductionThe Dementias Platform UK (DPUK) Data Portal is a secure, accessible environment facilitating provision of rich data towards the largest Dementia, cognition and ageing community of cohort studies in the world. DPUK is also providing services for cohort studies and researchers to maximise the research potential of the programme’s community. Objectives and ApproachAs part of the engagement of DPUK cohorts with the Data Portal, cohorts will upload data onto the DPUK instance of UK Secure eResearch Platform infrastructure. The Data Portal allows access to a collaborative working space that allows cohorts to enrich their own data, perform their own analysis, and enhance the research potential of their data whilst making use of expertise at various DPUK sites, such as data linking, curation and multi-modal specialism. Cohort data divided into ontologies allows researchers to access data specific to their study needs and can be requested from multiple cohorts simultaneously. ResultsBy utilising the Data Portal researchers have access to cohort data that has been prepared for dementia epidemiology using the agreed ontologies, providing more rapid access to cohort data that otherwise may be large and complex. The knowledge and experience of DPUK staff and collaborators can also help to guide nascent cohorts and feasibility studies into producing research-ready datasets, enabling them to achieve greater impact with their data. A range of analytical tools are provided on the Data Portal making analysis of a cohort’s own data or multiple independent datasets more accessible. Alongside data curation, DPUK also facilitates data linkage to routine sources, beginning with a Wales-wide use case that will expand to the UK over the course of the project. Conclusion/ImplicationsData from international sources accessible using a central platform permits international collaboration, with ontologies allowing previously disparate data to be combined and analysed to build knowledge and research impact. DPUK projects create policy leading results and operational research standards, enhancing cohort impact and discovery of benefits for Dementia patients.

Dementias Platform UK (DPUK) Data Portal - World-leading infrastructure facilitating innovative multi-modal research

IntroductionModern team science requires effective sharing of data and skills. The DPUK Data Portal is a collection of tools, datasets and networks that allows for epidemiologists and specialist researchers alike to access, analyse and investigate cohort and different modalities of routine data across UK and international sources. Objectives and ApproachThe Portal is housed on an instance of UKSeRP (UK Secure eResearch Platform), that allows customisable infrastructure to be used for multi-modal research (thus far live in genetics, imaging and clinical data) for researchers across the world using remote access technology whilst allowing governance to remain with the data provider. A central team at Swansea University is responsible for data curation and processing, and runs an access procedure for researchers to apply to use data from multiple sources to be analysed in a central analysis environment. Other modalities are similarly hosted, with input from partner sites in Cardiff and Oxford. ResultsDPUK facilitates data access and research on 49 cohorts, 40 UK-based and 9 international. The centralised repository model including remote access and ability to store and make available different modalities of data, from phenotypic data, to genetic and imaging data, has allowed DPUK to begin to support research of varying topics, from those studying cognitive decline and Dementia as a disease, to those maturing analytical models. By providing access to data platforms specialising in genetics, imaging and routine clinical data, as well as to specialists in disease and biology to aid with its understanding, DPUK has realised a large-scale research exercise combining major data modalities on a central platform, and allow access to such rich data across the world under an umbrella of robust governance. Conclusion/ImplicationsGlobally, cohorts are pooling data, expertise and desire to enrich their own aims in partnership with a federated research community to enable in-depth scrutiny of the biological origins of dementia and the development and evaluation of novel approach to disease prevention and cure.

Dementias Platform UK (DPUK) Data Portal - supporting multi-modal data analysis, data linkage and real-world outcomes

DPUK relaunched the Data Portal in November 2017 to present openly available information on the data availability and technical capability of the Data Portal, which supports multi-modal research studies with various objectives from disease model validation to observation investigation.DPUK not only brings clinical data together from cohorts, but is now supporting multi-modal studies in genetics and imaging, as well as linkage opportunities to routine data using world-leading technical solutions to data sharing.The capacity, adaptability and sophistication of the UK Secure eResearch Platform which the Portal is housed on, allows for unprecedented levels of centralised access to rich cohort and routine data, which is consequentially leading to international collaboration and development ambition within epidemiology, bioinformatics, research methodology and technical research solutions.As of March 2018, DPUK is supporting 50 cohorts, 41 from the UK and 9 from across the rest of the world, alongside furthering links and access to routine data held in the UK and across the world. 20 research studies are underway, and the DPUK mission to enhance data science within dementia research is leading the conversation for developing a community of excellence in this field and across other research genres.

Hypoxic Challenge Testing for Fitness to Fly with Severe Asthma

INTRODUCTION

Commercial airline travel poses a recognized risk to patients with respiratory disease, including in those with asthma. Hypoxic challenge testing (HCT) is typically employed to mitigate this risk by dictating in-flight oxygen requirement.

METHODS

The role of HCT has not been formally studied in patients with severe asthma and we therefore evaluated HCT assessment in a cohort of patients with severe asthma (N = 37).

RESULTS

Over half (57%) of patients had a positive HCT. Baseline oxygen saturation (S(p)o(2)) was poorly predictive of a recommendation for supplementary oxygen in flight; two-thirds of those deemed to require oxygen had a baseline S(p)o(2) > 95%. A combination of any two of: P(a)o(2) ≤ 10.5 kPa, FEV(1) ≤ 60% predicted, and PEF ≤ 350 L · min(-1) predicted the need for in-flight oxygen with a sensitivity of 89% and a specificity of 69%. Furthermore, no patient with an S(p)o(2) > 95% and FEV(1) > 85% predicted had a positive HCT.

CONCLUSION

Overall, the findings indicate that HCT should be considered for all patients with severe asthma, regardless of resting oxygen saturation level.

Serotonin markers show altered transcription levels in an experimental pig model of mitral regurgitation

Serotonin (5-hydroxytryptamine, 5-HT) signalling is implicated in the pathogenesis of myxomatous mitral valve disease (MMVD) through 5-HT1B receptor (R), 5-HT2AR and 5-HT2BR-induced myxomatous pathology. Based on increased tryptophan hydroxylase-1 (TPH-1) and decreased serotonin re-uptake transporter (SERT) in MMVD-affected valves, increased valvular 5-HT synthesis and decreased clearance have been suggested. It remains unknown how haemodynamic changes associated with mitral regurgitation (MR) affect 5-HT markers in the mitral valve, myocardium and circulation. Twenty-eight pigs underwent surgically induced MR or sham-operation, resulting in three MR groups: control (CON, n = 12), mild MR (mMR, n = 10) and severe MR (sMR, n = 6). The gene expression levels of 5-HT1BR, 5-HT2AR, 5-HT2BR, SERT and TPH-1 were analysed using quantitative PCR (qPCR) in the mitral valve (MV), anterior papillary muscle (AP) and left ventricle (LV). MV 5-HT2BR was also analysed with immunohistochemistry (IHC) in relation to histological lesions and valvular myofibroblasts. All 5-HTR mRNAs were up-regulated in MV compared to AP and LV (P <0.01). In contrast, SERT and TPH-1 were up-regulated in AP and LV compared to MV (P <0.05). In MV, mRNA levels were increased for 5-HT2BR (P = 0.02) and decreased for SERT (P = 0.03) in sMR vs. CON. There were no group differences in 5-HT2BR staining (IHC) but co-localisation was found with α-SMA-positive cells in 91% of all valves and with 33% of histological lesions. In LV, 5-HT1BR mRNA levels were increased in sMR vs. CON (P = 0.01). In conclusion, these data suggest that MR may affect mRNA expression of valvular 5-HT2BR and SERT, and left ventricular 5-HT1BR in some pigs.

Depersonalised doctors: a cross-sectional study of 564 doctors, 760 consultations and 1876 patient reports in UK general practice

OBJECTIVES

The objectives of this study were to assess burnout in a sample of general practitioners (GPs), to determine factors associated with depersonalisation and to investigate its impact on doctors' consultations with patients.

DESIGN

Cross-sectional, postal survey of GPs using the Maslach Burnout Inventory (MBI). Patient survey and tape-recording of consultations for a subsample of respondents stratified by their MBI scores, gender and duration of General Medical Council registration.

SETTING

UK general practice.

PARTICIPANTS

GPs within NHS Essex.

PRIMARY AND SECONDARY OUTCOME MEASURES

Scores on MBI subscales (depersonalisation, emotional exhaustion, personal accomplishment); scores on Doctors' Interpersonal Skills Questionnaire and patient-centredness scores attributed to tape-recorded consultations by independent observers.

RESULTS

In the postal survey, 564/789 (71%) GPs completed the MBI. High levels of emotional exhaustion (261/564 doctors, 46%) and depersonalisation (237 doctors, 42%) and low levels of personal accomplishment (190 doctors, 34%) were reported. Depersonalisation scores were related to characteristics of the doctor and the practice. Male doctors reported significantly higher (p<0.001) depersonalisation than female doctors. Doctors registered with the General Medical Council under 20 years had significantly higher (p=0.005) depersonalisation scores than those registered for longer. Doctors in group practices had significantly higher (p=0.001) depersonalisation scores than single-handed practitioners. Thirty-eight doctors agreed to complete the patient survey (n=1876 patients) and audio-record consultations (n=760 consultations). Depersonalised doctors were significantly more likely (p=0.03) to consult with patients who reported seeing their 'usual doctor'. There were no significant associations between doctors' depersonalisation and their patient-rated interpersonal skills or observed patient-centredness.

CONCLUSIONS

This is the largest number of doctors completing the MBI with the highest levels of depersonalisation reported. Despite experiencing substantial depersonalisation, doctors' feelings of burnout were not detected by patients or independent observers. Such levels of burnout are, however, worrying and imply a need for action by doctors themselves, their medical colleagues, professional bodies, healthcare organisations and the Department of Health.

Cross-sectional imaging in non-melanoma skin cancer of the head and neck

AIM

To investigate in head and neck non-melanoma skin cancers (NMSCs) the accuracy of cross-sectional imaging for detection of local tumour extent, recurrent tumour and prediction of patient outcome.

METHODS

This retrospective study included 33 NMSC patients (22 men, 11 women, median age 69 years) with 8 primary and 25 suspected recurrent tumours. The findings of magnetic resonance imaging (MRI) and computed tomography (CT) were compared with histopathology, and accuracy of MRI or CT in detecting local recurrence was determined. Extent of disease on imaging was compared with patient outcome assessed by clinical follow-up to a mean of 26.4 months.

RESULTS

Lesions were identified in 29 patients, whose mean disease-free survival (DFS) was 25.5 months. In 4 of these cases, where imaging showed no invasion of deep structures, DFS was 56 months. In the other 25 cases DFS was 20.6 months, irrespective of treatment but varying with site of involvement. Of 19 patients treated with surgery, imaging of 16 showed deep invasion, which was confirmed at histology in 15 (93.7% accuracy), and 3 had superficial tumours on imaging all confirmed by histology (100% accuracy). Imaging accuracy for identifying recurrent tumour was 96% (24 of 25 patients).

CONCLUSION

In NMSC, cross-sectional imaging accurately identifies tumour extent and local recurrence. The extent of disease and invasion of deeper structures predicts patient outcome.

Microtubule assembly in cultured myoblasts and myotubes following nocodazole induced microtubule depolymerisation

When myoblasts fuse into myotubes, the organisation of the cytoskeleton changes dramatically. For example, microtubules emanate in a radial array form the centrosome in myoblasts, but form linear arrays not linked to a centrosome in myotubes. It is not clear how these linear arrays are formed and nucleated. They could arise in a number of ways: by nucleation and release from centrosomal like structures, cytoplasmic assembly, breakage/severing or nucleation from non-centrosomal sites. To test which of the above mechanisms or combination of mechanisms are responsible we investigated the re-formation of microtubules after depolymerisation by nocodazole, using antibodies against pericentrin, gamma-tubulin, EB1, and tyrosinated alpha-tubulin. In myoblasts, we found that when microtubules were allowed to recover after complete depolymerisation with nocodazole, microtubule recovery began within 1 min and was complete after 5 min. Microtubules grew out from the centrosome, which was positively stained for gamma-tubulin or pericentrin. In untreated myotubes, microtubules were arranged in linear arrays, with EB1 at their ends. The pericentriolar protein, pericentrin was arranged in a band around the nucleus as well as discrete spots in the cytoplasm. In contrast, the microtubule nucleating protein gamma-tubulin was not found in a band around the nucleus, but was found in several punctuate spots throughout the cytoplasm. Further, when microtubules were allowed to recover, after complete depolymerisation with nocodazole, recovery was not as rapid as that seen in myoblasts, and we found that regrowth began with the formation of short microtubule fragments throughout the cytoplasm. Gamma-tubulin was associated with these fragments. These results suggest that in myotubes, nucleation of microtubules can be non-centrosomal.

The American Brachytherapy Society recommendations for high-dose-rate brachytherapy for carcinoma of the cervix

PURPOSE

This report presents guidelines for using high-dose-rate (HDR) brachytherapy in the management of patients with cervical cancer, taking into consideration the current availability of resources in most institutions.

METHODS

Members of the American Brachytherapy Society (ABS) with expertise in HDR brachytherapy for cervical cancer performed a literature review, supplemented their clinical experience to formulate guidelines for HDR brachytherapy of cervical cancer.

RESULTS

The ABS strongly recommends that definitive irradiation for cervical carcinoma must include brachytherapy as a component. Each institution should follow a consistent treatment policy when performing HDR brachytherapy, including complete documentation of treatment parameters and correlation with clinical outcome, such as pelvic control, survival, and complications. The goals are to treat Point A to at least a total low-dose-rate (LDR) equivalent of 80-85 Gy for early stage disease and 85-90 Gy for advanced stage. The pelvic sidewall dose recommendations are 50-55 Gy for early lesions and 55-65 Gy for advanced ones. The relative doses given by external beam radiation therapy (EBRT) vs. brachytherapy depend upon the initial volume of disease, the ability to displace the bladder and rectum, the degree of tumor regression during pelvic irradiation, and institutional preference. As with LDR brachytherapy, every attempt should be made to keep the bladder and rectal doses below 80 Gy and 75 Gy LDR equivalent doses, respectively. Interstitial brachytherapy should be considered for patients with disease that cannot be optimally encompassed by intracavitary brachytherapy. While recognizing that many efficacious HDR fractionation schedules exist, some suggested dose and fractionation schemes for combining the EBRT with HDR brachytherapy for each stage of disease are presented. These recommendations are intended only as guidelines, and the suggested fractionation schemes have not been thoroughly tested. The responsibility for the medical decisions ultimately rests with the treating radiation oncologist.

CONCLUSION

Guidelines are established for HDR brachytherapy for cervical cancer. Practitioners and cooperative groups are encouraged to use these guidelines to formulate their treatment and dose-reporting policies. These guidelines will be modified, as image-based treatment becomes more widely available.

American brachytherapy society recommendations for clinical implementation of NIST-1999 standards for (103)palladium brachytherapy. The clinical research committee of the American Brachytherapy Society

PURPOSE

Recent important developments in palladium-103 ((103)Pd) dosimetry mandate a reevaluation of (103)Pd brachytherapy prescribing practices.

METHODS AND MATERIALS

The clinical research committee of the American Brachytherapy Society (ABS) convened a consensus session of brachytherapists and physicists to develop recommendations regarding future dose prescribing guidelines for National Institute of Standards and Technology (NIST-1999) calibrated (103)Pd sources.

RESULTS

The ABS recommends that clinicians attempt to reproduce the implant doses delivered and reported in the literature through the past decade.

CONCLUSIONS

The following should be immediately implemented for (103)Pd dosimetry: 1) All practicing physicians, physicists, dosimetrists, and suppliers implement NIST-1999 air-kerma strength standard for (103)Pd brachytherapy. 2) All treatment planning systems and dose calculation algorithms must be updated to reflect new dose rate constants. The AAPM-recommended validated value for Theraseed model 200 is 0.665 cGy h(-1) U(-1). The dose rate constant for the Mentor MED3633 seed is currently reported as 0.68 cGy h(-1) U(-1). This latter value and the values for seeds from other manufacturers are awaiting independent confirmation. 3) Physicians who previously prescribed 115 Gy for (103)Pd monotherapy prostate implants should now prescribe 125 Gy. When using (103)Pd as a boost following 45 Gy of external beam irradiation, 100 Gy should be prescribed instead of the previous 90 Gy. It is critical that all three changes be implemented concurrently, because they are interdependent.

Combined low-dose-rate brachytherapy and external beam radiation for cervical cancer: experience over ten years

Cervical cancer was treated with a combination of external beam and intracavitary radiation during a 10-year period at Wayne State University. Data were collected for 216 patients treated radically with external beam radiation (EBRT) and low-dose-rate brachytherapy for cervical cancer between 1980 and 1991 at Wayne State University. Patient distribution by stage was IB, 20.8%; IIA, 7.4%; IIB, 26.9%; IIIA, 1.8%; IIIB, 40.7%; and IVA, 2.3 %. Survival curves were constructed using Kaplan-Meier methods and differences between groups were tested for significance using the log-rank test. Multivariate analysis was done using the Cox proportional hazards model. With a median follow-up of 114 months, actuarial disease-free survival for all patients was 60% at 5 years and 55% at 10 years. Actuarial 5-year survival for Stage IB was 79%; for Stage II, 59%; and for Stage III, 53%. There were 14/216 (6%) of patients with severe late complications. On univariate analysis, race was found to be statistically significant, with Caucasian patients having better survival than African American (P = 0.03). The survival for patients treated in shorter overall times was significantly higher (P<0.001), especially with treatment completion in under 58 days. The stepwise Cox multivariate analysis provided the following significant results: race (African American vs. Caucasian; P = 0.04, RR = 1.6), Stage (II vs. I, P = 0.004, RR = 2.6), Stage (III vs. I; P = 0.004, RR = 2.5), and overall treatment time (P = 0.006, RR = 1.62). Rates of local control, survival, and complications among women treated with combined external beam and intracavitary radiation for cervix cancer were similar to those of prior retrospective studies.

Neutron and photon clonogenic survival curves of two chemotherapy resistant human intermediate-grade non-Hodgkin lymphoma cell lines

BACKGROUND

The potential role of neutron therapy in the management of intermediate-grade non-Hodgkin lymphoma (IGNHL) has not been examined because of the belief that the anticipated radiobiological effectiveness (RBE) would be uniformly very low.

PURPOSE

To determine the fast neutron RBE for two chemotherapy-resistant IGNHL cell lines.

METHODS AND MATERIALS

Conventional soft agar clonogenic survival curves following irradiation by 60Co and fast neutron were established for two IGNHL cell lines. These cell lines, WSU-DLCL2 and SK-DHL2B, were found in previous studies to be able to repair sublethal damage, and were also resistant to L-Pam and doxorubicin chemotherapy.

RESULTS

When the surviving fraction after 2 Gy photon was chosen as the biological endpoint, the RBE for WSU-DLCL2 and SK-DHL2B measured 3.34 and 3.06. Similarly, when 10% survival was considered, the RBE for these two cell lines measured 2.54 and 2.59. The RBE, as measured by the ratios alpha neutron/alpha photon, for WSU-DLCL2, SK-DHL2B cell lines are 6.67 and 5.65, respectively. These results indicate that the RBE for these IGNHL cell lines is higher than the average RBE for cell lines of other histological types.

CONCLUSION

Fast neutron irradiation may be of potential value in treating selected cases of IGNHL.

Radiobiological characterization of two human chemotherapy-resistant intermediate grade non-Hodgkin's lymphoma cell lines

Intermediate grade non-Hodgkin's lymphoma (IGNHL) is generally considered a radiosensitive tumor that can be controlled with moderate radiation doses. Cell-survival curves of cell lines derived from IGNHL have been typically described to exhibit small or no shoulder, implying inability to accumulate or repair sublethal radiation damage. We characterize in this report the clonogenic radiation survival curves of two human IGNHL cell lines, WSU-DLCL2 and SK-DHL2B, established from patients who expired after having exhibited chemotherapy resistance of their tumors. The cells were irradiated with 60Co radiation at a dose rate of 85-100 cGy/min and cell survival data were analyzed according to the linear quadratic model. The alpha/beta values for WSU-DLCL2 and SK-DHL2B cells are 2 and 8.6, respectively. The corresponding SF2 are 0.42 and 0.35, respectively. Both cell lines are able to repair radiation-induced sublethal damage. These data indicate that these cells are only moderately radiosensitive.

The American brachytherapy society survey of brachytherapy practice for carcinoma of the cervix in the United States

PURPOSE

The purpose of this study was to survey the brachytherapy practice for cervical cancer in the United States.

METHODS

The Clinical Research Committee of the American Brachytherapy Society (ABS) performed a retrospective survey of individual physicians of the ABS and American Society of Therapeutic Radiologists and Oncologists regarding the details of the brachytherapy techniques they personally used in the treatment of cervical cancer patients for the year 1995. The replies (some of which may have been an estimate only) were tabulated. The scope of this survey did not allow us to verify the data by chart audits.

RESULTS

A total of about 3500 questionnaires were mailed out; 521 responses were received. Of these responders, 206 (40%) did not perform any brachytherapy for carcinoma of the cervix in 1995. Of the other 315 responders reporting a total of 4892 patients treated in 1995, 88% used low dose rate (LDR) while 24% used high dose rate (HDR). There was a wide variation in the doses used. For LDR treatments, the median total external beam radiation therapy (EBRT) dose was 45 and 50 Gy and the LDR dose was 42 and 45 Gy for early and advanced cancers, respectively. For HDR treatments, the median EBRT dose was 48 and 50 Gy and the median HDR dose was 29 and 30 Gy for early and advanced cancers, respectively. The median dose per fraction was 6 Gy for a median of five fractions. Interstitial brachytherapy was used as a component of the treatment in 6% of the patients by 21% of responders. Very few responders treated with pulsed or medium dose rates.

CONCLUSION

This retrospective survey showed the current brachytherapy practice pattern in the treatment of cervical cancer in the United States and can serve as a basis for future prospective national brachytherapy data registry. There was wide variation in the practice pattern, emphasizing the urgent need for consensus on these issues.

Multifractionated high-dose-rate brachytherapy with concomitant daily teletherapy for cervical cancer

BACKGROUND

High-dose-rate (HDR) brachytherapy has been the preferred treatment for cervical cancer at Wayne State University since 1987. The outcome of the first 105 patients treated is analyzed.

PURPOSE

To determine clinical efficacy of the HDR modality.

METHODS

We reviewed 105 patients and evaluated the 88 patients treated for cervical carcinoma with HDR and external beam radiotherapy (EBRT) from August 1987 to December 1992. Patients received initial external radiation to the pelvis (total dose of 19.8 to 39.6 Gy in 11 to 22 fractions), followed by outpatient HDR brachytherapy (3 fractions/week, 386 cGy/fraction to Point A, total of 8 to 12 fractions) and concurrent daily EBRT (1.8 to 2.0 Gy) to lateral parametria. During the HDR period of treatment, step wedge transmission blocks were used to shield central pelvic tissue while treating peripheral pelvic tissues with EBRT. Patient distributions were as follows: 25, IB/IIA; 35, IIB/IIIA; and 28, IIIB/IVA. There were 56 African American and 32 Caucasian patients with mean age of 55 (range 19-89). The median follow-up was 33 months (range 20 to 76 months). Kaplan-Meier analysis was performed.

RESULTS

Three-year survival rates were 88%, IB/IIA; 69%, IIB/IIIA; 56%, IIIB/IVA; and 72% overall. Local control was achieved in 71/88 (80%) of patients. Failure site was cervix or within the pelvis in 12 patients, distant metastasis only 17 patients, and combined local and distant in 5 patients. Of the failures, 82% (28/34) died within 2 years. There were 3 grade III/complications (3.4%).

CONCLUSION

Results compare favorably with previous LDR experience.

Hyperfractionated conformal radiotherapy in locally advanced prostate cancer: results of a dose escalation study

PURPOSE

This study was initiated to assess the incidence of chronic complications and histologic and biochemical control following hyperfractionated conformal radiotherapy in patients with locally advanced prostate cancer.

METHODS AND MATERIALS

Between October 1991 and October 1994, 49 patients with locally advanced prostate cancer were entered on the first two dose levels of a prospective dose-escalation study using hyperfractionated three dimensional conformal radiotherapy. The first 25 patients received a minimum tumor dose of 78 Gy to the prostate and seminal vesicles in 6 weeks at 1.3 Gy, b.i.d. No increase in chronic toxicity compared with conventional radiotherapy was noted; therefore, an additional 24 patients were treated to a minimum tumor dose of 82.8 Gy to the prostate and seminal vesicles in 7 weeks at 1.15 Gy, b.i.d. Toxicity was scored according to the Radiation Therapy Oncology Group morbidity grading scale. Efficacy was assessed through scheduled postradiation prostate specific antigen values and ultrasound-guided biopsies. The median follow-up for the entire group was 20 months.

RESULTS

The hyperfractionated external radiation was well tolerated with minimal acute morbidity. At 30 months, the actuarial probability of Grade 2 gastrointestinal toxicity was 17%. At 30 months, the actuarial probability of Grade 2 genitourinary toxicity was 16%. There was no statistically significant difference between the two dose levels. No Grade 3 or 4 gastrointestinal or genitourinary toxicity was noted. At 12 months, 84% of patients had a prostate specific antigen < or = 4; and 53% < or = 1 ng/ml. At 12 months, 71% of patients had post radiation biopsies that were either negative (55% or showed a marked therapeutic effect (16%).

CONCLUSION

The use of hyperfractionated conformal radiotherapy facilitated dose escalation with no increase in chronic toxicity compared to standard doses. The initial tumor response based on prostate specific antigen measurements and postradiation biopsies is highly encouraging. Based on these results, an increase in dose to 87.4 Gy has been planned according to the schema of this ongoing dose escalation study.

Comparison of hyperfractionated conformal photon with conformal mixed neutron/photon irradiation in locally advanced prostate cancer

In an attempt to improve the probability of complication-free local control for patients with locally advanced prostate cancer, a series of dose-finding studies have been conducted at Wayne State University using conformal neutron and hyperfractionated photon irradiation. In total, 96 patients with locally advanced prostate cancer (T3/T4 N0/N1 M0, and/or Gleason score > or = 8) were treated in two prospective studies. Forty-seven patients received conformal neutron/photon (15 NGy + 18 PhGy) and 49 patients were treated in a dose-escalation study using conformal photons (25 patients/78 Gy and 24 patients/83 Gy minimum dose). The median follow-up for both studies was 20 months (range 6-36 months). There was no significant difference in the rate of chronic gastrointestinal (GI) or gastrourinary (GU) morbidity between the two groups. However, the neutron treated patients had a significantly higher rate of moderate (14%) and severe (12%) hip stiffness. The rates of prostate-specific antigen (PSA) decline and 12-month negative biopsy were comparable. In conclusion, the therapeutic gain of neo-adjuvant hormonal therapy in combination with photon hyperfractionation to 83 Gy appears identical to that seen with the mixed neutron-photon dose of 15 NGy + 18 PhGy. Further efforts at improving the therapeutic ratio of radiotherapy for patients with locally advanced prostate cancer should be undertaken.

Concurrent outbreaks of pertussis and Mycoplasma pneumoniae infection: clinical and epidemiological characteristics of illnesses manifested by cough

Concurrent outbreaks of illnesses that were manifested by cough and that were suspected to be due to Bordetella pertussis and Mycoplasma pneumoniae infection were investigated in a midwestern town in Illinois. Three studies were conducted: questionnaires on the clinical and epidemiological characteristics of illness were administered to patients; serological tests were performed to confirm the presence of each pathogen and to develop case definitions for each illness; and case definitions were applied to responses to a mail-in questionnaire for estimating the magnitude of both outbreaks. In 135 cases of suspected pertussis and 42 cases of suspected mycoplasmal infection, subjects had a cough for > or = 14 days (the pertussis outbreak case definition). Among 20 laboratory-confirmed cases, a cough for > or = 14 days had a specificity of 20% for pertussis, and a cough for > or = 28 days plus whoop and/or vomiting had a specificity of 90% for pertussis. Six hundred-seventeen pertussis cases per 100,000 population and 1,179 cases of M. pneumoniae infection per 100,000 population occurred. In this setting, the standard outbreak case definition for pertussis lacked adequate specificity to distinguish pertussis from mycoplasmal infection. The magnitude of each outbreak was greater than the number of reported cases suggested.

Preliminary results of a hyperfractionated dose escalation study for locally advanced adenocarcinoma of the prostate

The objective of this study was to build on our experience with 3-D conformal radiotherapy (CRT) by using a hyperfractionated dose escalation scheme to maximize the therapeutic ratio between improved local control and reduced morbidity in patients with locally advanced prostate cancer. Twenty patients with locally advanced (T3, T4) adenocarcinoma of the prostate were treated with a hyperfractionated radiotherapy schedule. All fields were designed with a conformal therapy based beam's eye view, 3-D planning system. The pelvic lymph nodes received 1.8 Gy/day to a total dose of 45 Gy in 5 weeks. Using partial transmission blocks, the prostate and periprostatic tissues received 1.3 Gy twice daily (minimum interval of 6 h) to a total dose of 78 Gy in 6 weeks. The dose was chosen by calculating the biologically effective dose (BED) which would produce the same effect in late reacting tissue but an increase for the tumor as our standard dose of 69 Gy delivered in 1.8-2.0 Gy fractions. The alpha/beta chosen for late damage was 3 Gy and 10 Gy was used for the tumor. All 20 patients completed the planned course of treatment. Although an increase in the tumor BED would be expected to result in increased acute effects, no significant worsening of acute side-effects was observed compared with standard treatment. All patients had only mild (Grade 1) rectal or bladder toxicity during treatment. One patient had an exacerbation of diverticulitis during treatment requiring hospitalization for antibiotics but completed treatment on schedule.(ABSTRACT TRUNCATED AT 250 WORDS)

Initial experience with a practical hyperfractionated accelerated radiotherapy regimen

This paper presents early results of a trial of a three-fractions-per-day (TID) regimen that is more convenient to schedule than the Continuous Hyperfractionated Accelerated Radiotherapy (CHART) protocol currently being tested in Europe. The treatment schedule used in the CHART regimen has been modified from 36 fractions of 1.5 Gy TID in 12 days to 72 fractions of 1.1 Gy in 24 treatment days, with all fractions delivered during normal working hours. With no weekend treatments, the entire course of radiotherapy is completed in less than 5 weeks. The doses used were determined using the L-Q model, with correction for incomplete repair between fractions and for accelerated repopulation of cancer cells. Comparison with historical controls shows statistically significant improvements both in CR rates for the primary tumor and in acute toxicity, as measured by reduced treatment interruptions. L-Q model calculations predict that, compared to the highest dose achieved in previous studies without exceeding tolerance, we are able to obtain a 12% increase in bioeffect dose to the primary tumor due to accelerating the treatment. An analysis of the potential tumoricidal effectiveness of this new treatment regimen shows that it should be better than several other accelerated fractionation schedules being tested for all values of Tpot. For short Tpot times, the advantage may be as much as one log cell kill, corresponding to a 10-15% potential improvement in local control.

Neonatal calves develop airflow limitation due to chronic hypobaric hypoxia

Neonates and infants presenting with pulmonary hypertension and chronic hypoxia often exhibit airway obstruction. To investigate this association, we utilized a system in which neonatal calves are exposed to chronic hypobaric hypoxia and develop severe pulmonary hypertension. For the present study, one of each pair of six age-matched pairs of neonatal calves was continuously exposed to hypobaric hypoxia at 4,500 m (CH); the other remained at 1,500 m. At 2 wk of age, mean pulmonary arterial pressure (MPAP), dynamic lung compliance (Cdyn), resistance (RL), and static respiratory system compliance (Crs) were measured at 4,500 m in both CH and control calves exposed acutely to hypoxia (C). These measurements were repeated after cumulative administrations of nebulized methacholine (MCh). Tissues were removed for histological examination and assessment of bronchial ring contractility to MCh and KCl. After 2 wk of hypobaric hypoxia, MPAP (C 35 +/- 1.7 vs. CH 120 +/- 7 mmHg, P less than 0.001) and RL (C 2.64 +/- 0.16 vs CH 4.99 +/- 0.47 cmH2O.l-1s, P less than 0.001) increased. Cdyn (C 0.100 +/- 0.01 vs. CH 0.082 +/- 0.007 l/cmH2O) and Crs (CH 0.46 +/- 0.003 vs. C 0.59 +/- 0.009 l/cmH2O) were not significantly different. Compared with airways of C calves, airways of CH animals did not exhibit in vivo or in vitro MCh hyperresponsiveness; however, in vitro contractility to KCl of airways from CH animals was significantly increased. Histologically, airways from the CH calves showed increases in airway fibrous tissue and smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiation exposure to patients receiving routine scoliosis radiography measured at depth in an anthropomorphic phantom

Concern about the amount of radiation received during scoliosis evaluation and treatment led us to measure radiation exposure in an anthropomorphic phantom to determine the increased risk of breast cancer in young women with scoliosis. Assuming that 22 radiographic examinations were performed over the course of scoliosis treatment, the increased relative risk of breast cancer was determined to be 0.22% in these patients.

Separating output factor into collimator factor and phantom scatter factor for megavoltage photon calculations

Output factor has been used in megavoltage dosage calculations because collimator factor and backscatter factor are considered individually indeterminable. Output factor reflects the normalized product of backscatter factor and collimator factor for the most common treatment geometry. A method has been found for independently measuring collimator factors for megavoltage photons. Using a build-up cap of high density tissue equivalent material, we have measured the relative collimator factors for various units with photon energies up to 15 MV. Utilizing measured values for output factor and collimator factor relative backscatter factors have been determined.