Clinical impact of dosimetry quality assurance programmes assessed by radiobiological modelling of data from the thermoluminescent dosimetry study of the European Organization for Research and Treatment of Cancer

Quality assurance in a phase III, multicenter, randomized trial of POstmastectomy radioThErapy in Node posiTive breast cancer with or without Internal mAmmary nodaL irradiation (POTENTIAL): a planning benchmark case

PURPOSE

To report the planning benchmark case results of the POTENTIAL trial-a multicenter, randomized, phase 3 trial-to evaluate the value of internal mammary nodal (IMN) irradiation for patients with high-risk breast cancer.

METHODS

All participating institutions were provided the outlines of one benchmark case, and they generated radiation therapy plans per protocol. The plans were evaluated by a quality assurance team, after which the institutions resubmitted their revised plans. The information on beams arrangement, skin flash, inhomogeneity corrections, and protocol compliance was assessed in the first and final submission.

RESULTS

The plans from 26 institutions were analyzed. Some major deviations were found in the first submission. The protocol compliance rates of dose coverage for the planning target volume of chest wall, supraclavicular fossa plus axilla, and IMN region (PTVim) were all significantly improved in the final submission, which were 96.2% vs. 69.2%, 100% vs. 76.9%, and 88.4% vs. 53.8%, respectively. For OARs, the compliance rates of heart Dmean, left anterior descending coronary artery V40Gy, ipsilateral lung V5Gy, and stomach V5Gy were significantly improved. In the first and final submission, the mean values of PTVim V100% were 79.9% vs. 92.7%; the mean values of heart Dmean were 11.5 Gy vs. 9.7 Gy for hypofractionated radiation therapy and 11.5 Gy vs. 11.0 Gy for conventional fractionated radiation therapy, respectively.

CONCLUSION

The major deviations were corrected and protocol compliance was significantly improved after revision, which highlighted the importance of planning benchmark case to guarantee the planning quality for multicenter trials.

Radiotherapy quality assurance in paediatric clinical trials: first report from six QUARTET-affiliated trials

BACKGROUND AND PURPOSE

SIOP Europe's QUARTET project launched in 2016; aiming to improve access to high-quality radiotherapy for children and adolescents treated within clinical trials across Europe. The aim of this report is to present the profile of institutions participating in six QUARTET-affiliated trials and a description of the initial individual case review (ICR) outcomes.

METHODS

This is a two-part analysis. Firstly, using facility questionnaires, beam output audit certificates, and advanced technique credentialing records to create a profile of approved institutions, and secondly, collating trial records for ICRs submitted prior to 31/10/2022. Trials included are: SIOPEN HR-NBL1, SIOPEN-LINES, SIOPEN- VERITAS, SIOP-BTG HRMB, EpSSG-FaR-RMS, and SIOPEN HR-NBL2.

RESULTS

By 31/10/2022, a total of 103 institutions had commenced QUARTET site approval procedures to participate in QUARTET-affiliated trials; 66 sites across 20 countries were approved. These participating institutions were often paediatric referral sites with intensity modulated radiotherapy or proton beam therapy, designated paediatric radiation oncologists, and paediatric adapted facilities and imaging protocols available. In total, 263 patient plans were submitted for ICR, 254 ICRs from 15 countries were completed. ICRs had a rejection rate of 39.8%, taking an average of 1.4 submissions until approval was achieved. Target delineation was the most frequent reason for rejection.

CONCLUSION

The QUARTET facility questionnaire is a valuable tool for mapping resources, personnel, and technology available to children and adolescents receiving radiotherapy. Prospective ICR is essential for paediatric oncology clinical trials and should be prioritised to reduce protocol violations.

Quality improvements in radiation oncology clinical trials

Clinical trials have become the primary mechanism to validate process improvements in oncology clinical practice. Over the past two decades there have been considerable process improvements in the practice of radiation oncology within the structure of a modern department using advanced technology for patient care. Treatment planning is accomplished with volume definition including fusion of multiple series of diagnostic images into volumetric planning studies to optimize the definition of tumor and define the relationship of tumor to normal tissue. Daily treatment is validated by multiple tools of image guidance. Computer planning has been optimized and supported by the increasing use of artificial intelligence in treatment planning. Informatics technology has improved, and departments have become geographically transparent integrated through informatics bridges creating an economy of scale for the planning and execution of advanced technology radiation therapy. This serves to provide consistency in department habits and improve quality of patient care. Improvements in normal tissue sparing have further improved tolerance of treatment and allowed radiation oncologists to increase both daily and total dose to target. Radiation oncologists need to define a priori dose volume constraints to normal tissue as well as define how image guidance will be applied to each radiation treatment. These process improvements have enhanced the utility of radiation therapy in patient care and have made radiation therapy an attractive option for care in multiple primary disease settings. In this chapter we review how these changes have been applied to clinical practice and incorporated into clinical trials. We will discuss how the changes in clinical practice have improved the quality of clinical trials in radiation therapy. We will also identify what gaps remain and need to be addressed to offer further improvements in radiation oncology clinical trials and patient care.

Quantification of the uncertainties within the radiotherapy dosimetry chain and their impact on tumour control

BACKGROUND AND PURPOSE

Dose delivered during radiotherapy has uncertainty arising from a number of sources including machine calibration, treatment planning and delivery and can impact outcomes. Any systematic uncertainties will impact all patients and can continue for extended periods. The impact on tumour control probability (TCP) of the uncertainties within the radiotherapy calibration process has been assessed.

MATERIALS AND METHODS

The linear-quadratic model was used to simulate the TCP from two prostate cancer and a head and neck (H&N) clinical trial. The uncertainty was separated into four components; 1) initial calibration, 2) systematic shift due to output drift, 3) drift during treatment and 4) daily fluctuations. Simulations were performed for each clinical case to model the variation in TCP present at the end of treatment arising from the different components.

RESULTS

Overall uncertainty in delivered dose was +/-2.1% (95% confidence interval (CI)), consisting of uncertainty standard deviations of 0.7% in initial calibration, 0.8% due to subsequent calibration shift due to output drift, 0.1% due to drift during treatment, and 0.2% from daily variations. The overall uncertainty of TCP (95% CI) for a population of patients treated on different machines was +/-3%, +/-5%, and +/-3% for simulations based on the two prostate trials and H&N trial respectively.

CONCLUSION

The greatest variation in delivered target volume dose arose from calibration shift due to output drift. Careful monitoring of beam output following initial calibration remains vital and may have a significant impact on clinical outcomes.

EFOMP survey results on national radiotherapy dosimetry audits

PURPOSE

The Council Directive 2013/58/EURATOM entered into force in 2014, and its transposition into national legislations became applicable in 2018. The Council Directive 2013/58/EURATOM strengthened the importance of clinical audits, and stated that Member States should ensure dosimetry audit compliance in accordance with national procedures. Therefore, the purpose of this work was to picture the status of the implementation of dosimetry audits in European countries.

METHODS

A questionnaire was designed to describe dosimetry audit standards in radiotherapy across European countries. The questionnaire was sent to 33 EFOMP National Member Organizations (NMO).

RESULTS

Nineteen NMOs responded to the survey (14 EU members). For 58% of the participating countries national regulations required dosimetry audits in radiotherapy departments. In 37% of the participating countries there were implemented regulations for independent/secondary dose verification, and in 21% of the participating countries similar procedures for dose verification were already implemented although not regulated by law. In 42% of the participating countries there were implemented mechanisms to review updates and advances in the field of radiotherapy.

CONCLUSIONS

The transposition and further implementation of the Council Directive 2013/59/EURATOM was scarce, leading to heterogeneities in national policies about dosimetry audits.

Offline Quality Assurance for Intensity Modulated Radiation Therapy Treatment Plans for NRG-HN001 Head and Neck Clinical Trial Using Knowledge-Based Planning

PURPOSE

This study aimed to investigate whether a disease site-specific, multi-institutional knowledge based-planning (KBP) model can improve the quality of intensity modulated radiation therapy treatment planning for patients enrolled in the head and neck NRG-HN001clinical trial and to establish a threshold of improvements of treatment plans submitted to the clinical trial.

METHODS AND MATERIALS

Fifty treatment plans for patients enrolled in the NRG-HN001 clinical trial were used to build a KBP model; the model was then used to reoptimize 50 other plans. We compared the dosimetric parameters of the submitted and KBP reoptimized plans. We compared differences between KBP and submitted plans for single- and multi-institutional treatment plans.

RESULTS

Mean values for the dose received by 95% of the planning target volume (PTV_6996) and for the maximum dose (D0.03cc) of PTV_6996 were 0.5 Gy and 2.1 Gy higher in KBP plans than in the submitted plans, respectively. Mean values for D0.03cc to the brain stem, spinal cord, optic nerve_R, optic nerve_L, and chiasm were 2.5 Gy, 1.9 Gy, 6.4 Gy, 6.6 Gy, and 5.7 Gy lower in the KBP plans than in the submitted plans. Mean values for Dmean to parotid_R and parotid_L glands were 2.2 Gy and 3.8 Gy lower in KBP plans, respectively. In 33 out of 50 KBP plans, we observed improvements in sparing of at least 7 organs at risk (OARs) (brain stem, spinal cord, optic nerves (R & L), chiasm, and parotid glands [R & L]). A threshold of improvement of OARs sparing of 5% of the prescription dose was established for providing the quality assurance results back to the treating institution.

CONCLUSIONS

A disease site-specific, multi-institutional, clinical trial-based KBP model improved sparing of OARs in a large number of reoptimized plans submitted to the NRG-HN001 clinical trial, and the model is being used as an offline quality assurance tool.

Current Status of Radiopharmaceutical Therapy

In radiopharmaceutical therapy (RPT), a radionuclide is systemically or locally delivered with the goal of targeting and delivering radiation to cancer cells while minimizing radiation exposure to untargeted cells. Examples of current RPTs include thyroid ablation with the administration of ¹³¹I, treatment of liver cancer with ⁹⁰Y microspheres, the treatment of bony metastases with ²²³Ra, and the treatment of neuroendocrine tumors with ¹⁷⁷Lu-DOTATATE. New RPTs are being developed where radionuclides are incorporated into systemic targeted therapies. To assure that RPT is appropriately implemented, advances in targeting need to be matched with advances in quantitative imaging and dosimetry methods. Currently, radiopharmaceutical therapy is administered by intravenous or locoregional injection, and the treatment planning has typically been implemented like chemotherapy, where the activity administered is either fixed or based on a patient's body weight or body surface area. RPT pharmacokinetics are measurable by quantitative imaging and are known to vary across patients, both in tumors and normal tissues. Therefore, fixed or weight-based activity prescriptions are not currently optimized to deliver a cytotoxic dose to targets while remaining within the tolerance dose of organs at risk. Methods that provide dose estimates to individual patients rather than to reference geometries are needed to assess and adjust the injected RPT dose. Accurate doses to targets and organs at risk will benefit the individual patients and decrease uncertainties in clinical trials. Imaging can be used to measure activity distribution in vivo, and this information can be used to determine patient-specific treatment plans where the dose to the targets and organs at risk can be calculated. The development and adoption of imaging-based dosimetry methods is particularly beneficial in early clinical trials. In this work we discuss dosimetric accuracy needs in modern radiation oncology, uncertainties in the dosimetry in RPT, and best approaches for imaging and dosimetry of internal radionuclide therapy.

Urethra-Sparing Stereotactic Body Radiation Therapy for Prostate Cancer: Quality Assurance of a Randomized Phase 2 Trial

PURPOSE

To present the radiation therapy quality assurance results from a prospective multicenter phase 2 randomized trial of short versus protracted urethra-sparing stereotactic body radiation therapy (SBRT) for localized prostate cancer.

METHODS AND MATERIALS

Between 2012 and 2015, 165 patients with prostate cancer from 9 centers were randomized and treated with SBRT delivered either every other day (arm A, n = 82) or once a week (arm B, n = 83); 36.25 Gy in 5 fractions were prescribed to the prostate with (n = 92) or without (n = 73) inclusion of the seminal vesicles (SV), and the urethra planning-risk volume received 32.5 Gy. Patients were treated either with volumetric modulated arc therapy (VMAT; n = 112) or with intensity modulated radiation therapy (IMRT; n = 53). Deviations from protocol dose constraints, planning target volume (PTV) homogeneity index, PTV Dice similarity coefficient, and number of monitor units for each treatment plan were retrospectively analyzed. Dosimetric results of VMAT versus IMRT and treatment plans with versus without inclusion of SV were compared.

RESULTS

At least 1 major protocol deviation occurred in 51 patients (31%), whereas none was observed in 41. Protocol violations were more frequent in the IMRT group (P < .001). Furthermore, the use of VMAT yielded better dosimetric results than IMRT for urethra planning-risk volume D_98% (31.1 vs 30.8 Gy, P < .0001), PTV D_2% (37.9 vs 38.7 Gy, P < .0001), homogeneity index (0.09 vs 0.10, P < .0001), Dice similarity coefficient (0.83 vs 0.80, P < .0001), and bladder wall V_50% (24.5% vs 33.5%, P = .0001). To achieve its goals volumetric modulated arc therapy required fewer monitor units than IMRT (2275 vs 3378, P <.0001). The inclusion of SV in the PTV negatively affected the rectal wall V_90% (9.1% vs 10.4%, P = .0003) and V_80% (13.2% vs 15.7%, P = .0003).

CONCLUSIONS

Protocol deviations with potential impact on tumor control or toxicity occurred in 31% of patients in this prospective clinical trial. Protocol deviations were more frequent with IMRT. Prospective radiation therapy quality assurance protocols should be strongly recommended for SBRT trials to minimize potential protocol deviations.

Remote dosimetric auditing of clinical trials: The need for vendor specific models to convert images to dose

INTRODUCTION

A previous pilot study has demonstrated the feasibility of a novel image-based approach for remote dosimetric auditing of clinical trials. The approach uses a model to convert in-air acquired intensity modulated radiotherapy (IMRT) images to delivered dose inside a virtual phantom. The model was developed using images from an electronic portal imaging device (EPID) on a Varian linear accelerator. It was tuned using beam profiles and field size factors (FSFs) of a series of square fields measured in water tank. This work investigates the need for vendor specific conversion models for image-based auditing. The EPID measured profile and FSF data for Varian (vendor 1) and Elekta (vendor 2) systems are compared along with the performance of the existing Varian model (VM) and a new Elekta model (EM) for a series of audit IMRT fields measured on vendor 2 systems.

MATERIALS AND METHODS

The EPID measured beam profile and FSF data were studied for the two vendors to quantify and understand their relevant dosimetric differences. Then, an EM was developed converting EPID to dose in the virtual water phantom using a vendor 2 water tank data and images from corresponding EPID. The VM and EM were compared for predicting vendor 2 measured dose in water tank. Then, the performance of the new EM was compared to the VM for auditing of 54 IMRT fields from four vendor 2 facilities. Statistical significance of using vendor specific models was determined.

RESULTS

Observed dosimetry differences between the two vendors suggested developing an EM would be beneficial. The EM performed better than VM for vendor 2 square and IMRT fields. The IMRT audit gamma pass rates were (99.8 ± 0.5)%, (98.6 ± 2.3)% and (97.0 ± 3.0)% at respectively 3%/3 mm, 3%/2 mm and 2%/2 mm with improvements at most fields compared with using the VM. For the pilot audit, the difference between gamma results of the two vendors was reduced when using vendor specific models (VM: P < 0.0001, vendor specific models: P = 0.0025).

CONCLUSION

A new model was derived to convert images from vendor 2 EPIDs to dose for remote auditing vendor 2 deliveries. Using vendor specific models is recommended to remotely audit systems from different vendors, however, the improvements found were not major.

An on-site audit system for dosimetry credentialing of intensity-modulated radiotherapy in Japanese Clinical Oncology Group (JCOG) clinical trials

PURPOSE

This study was undertaken to analyze the results of intensity-modulated radiotherapy (IMRT) dosimetry credentialing using a phantom in the Japanese Clinical Oncology Group clinical trials.

METHODS

All measurements were performed on-site. The IMRT phantom consisted of a phantom shell and a module. Two types of structures, including a C-shaped planning target volume (PTV) around a column-shaped organ at risk (OAR), were included in the module. Each participating institution was asked to image, plan, and treat the phantom. A prescription dose of 2Gy should cover 95% of the PTV. The plan should limit the maximum doses to the PTV and OAR to less than 110% and 60%, respectively. The pass criteria were ±3% in terms of chamber dosimetry and a difference in profile position ⩽2mm in the high-dose gradient area of film dosimetry. The positional difference was defined as the largest distance between the measured and calculated positions at doses of 60% or 80%. These tolerances were based on the Japanese Society for Radiation Oncology IMRT guidelines.

RESULTS

Credentialing was performed on a total of 44 treatment machines in 32 institutions from 2009 to 2015. All differences between measured and planned doses at the measurement points of the PTV were within 3%. The means±standard deviations of the positional differences were 1.0±0.4mm and 0.9±0.3mm without and with the phantom shell, respectively.

CONCLUSIONS

The dose differences and positional differences met the desired criteria in all institutions.

The Essentials of Locoregional Control in the Treatment of Gastric Cancer

Gastric cancer is the fourth most frequent cancer in the world. For curative treatment and local control of gastric cancer, surgery is essential. The extent of the lymph node dissection is still under debate. Only one available trial showed significantly increased overall survival, whereas in all other randomised trials no significant difference could be found.

As surgery alone often is not sufficient in the curative treatment in gastric cancer, different (neo)adjuvant treatment strategies have extensively been studied. The recently published MAGIC trial showed downstaging, downsizing and an improved overall survival for patients treated with perioperative chemotherapy, compared to surgery alone (difference 13%, p = 0.009). The INT 0116 trial on the other hand, demonstrated the benefit of postoperative chemoradiotherapy compared to surgery alone for patients with a curative resection of gastric cancer. However, the quality of resections in this trial was poor, illustrating the importance of standardisation by quality control. This could be done by the Maruyama index, which quantifies the likelihood of unresected disease.

In the Netherlands, the CRITICS trial has recently been launched, which will be a quality controlled trial comparing postoperative chemoradiotherapy and chemotherapy on survival and/or locoregional control in patients who receive neoadjuvant chemotherapy followed by a D1+ gastric resection.

Quality assurance for clinical trials

Cooperative groups, of which the Radiation Therapy Oncology Group is one example, conduct national clinical trials that often involve the use of radiation therapy. In preparation for such a trial, the cooperative group prepares a protocol to define the goals of the trial, the rationale for its design, and the details of the treatment procedure to be followed. The Radiological Physics Center (RPC) is one of several quality assurance (QA) offices that is charged with assuring that participating institutions deliver doses that are clinically consistent and comparable. The RPC does this by conducting a variety of independent audits and credentialing processes. The RPC has compiled data showing that credentialing can help institutions comply with the requirements of a cooperative group clinical protocol. Phantom irradiations have been demonstrated to exercise an institution's procedures for planning and delivering advanced external beam techniques (1-3). Similarly, RPC data indicate that a rapid review of patient treatment records or planning procedures can improve compliance with clinical trials (4). The experiences of the RPC are presented as examples of the contributions that a national clinical trials QA center can make to cooperative group trials. These experiences illustrate the critical need for comprehensive QA to assure that clinical trials are successful and cost-effective. The RPC is supported by grants CA 10953 and CA 81647 from the National Cancer Institute, NIH, DHHS.

Does quality of radiation therapy predict outcomes of multicenter cooperative group trials? A literature review

Central review of radiation therapy (RT) delivery within multicenter clinical trials was initiated in the early 1970s in the United States. Early quality assurance publications often focused on metrics related to process, logistics, and timing. Our objective was to review the available evidence supporting correlation of RT quality with clinical outcomes within cooperative group trials. A MEDLINE search was performed to identify multicenter studies that described central subjective assessment of RT protocol compliance (quality). Data abstracted included method of central review, definition of deviations, and clinical outcomes. Seventeen multicenter studies (1980-2012) were identified, plus one Patterns of Care Study. Disease sites were hematologic, head and neck, lung, breast, and pancreas. Between 0 and 97% of treatment plans received an overall grade of acceptable. In 7 trials, failure rates were significantly higher after inadequate versus adequate RT. Five of 9 and 2 of 5 trials reported significantly worse overall and progression-free survival after poor-quality RT, respectively. One reported a significant correlation, and 2 reported nonsignificant trends toward increased toxicity with noncompliant RT. Although more data are required, protocol-compliant RT may decrease failure rates and increase overall survival and likely contributes to the ability of collected data to answer the central trial question.

Radiotherapy protocol deviations and clinical outcomes: a meta-analysis of cooperative group clinical trials

BACKGROUND

Noncompliance with radiotherapy (RT) protocol guidelines has been linked to inferior clinical outcomes. We performed a meta-analysis of cooperative group trials to examine the association between RT quality assurance (QA) deviations and disease control and overall survival (OS).

METHODS

We searched MEDLINE and the Cochrane Central Register of Controlled Trials for multi-institutional trials that reported clinical outcomes in relation to RT QA results. Hazard ratios (HRs) describing the association between RT protocol noncompliance and patient outcomes were extracted directly from the original studies or calculated from survival curves. Inverse variance meta-analyses were performed to assess the association between RT QA deviations and OS. A second meta-analysis tested the association between RT QA deviations and secondary outcomes, including local or locoregional control, event-free survival, and relapse. Random-effects models were used in cases of statistically significant (P < .10) effect heterogeneity. The Egger test was used to detect publication bias. All statistical tests were two-sided.

RESULTS

Eight studies (four pediatric, four adult) met all inclusion criteria and were incorporated into this analysis. The frequency of RT QA deviations ranged from 8% to 71% (median = 32%). In a random-effects model, RT deviations were associated with a statistically significant decrease in OS (HR of death = 1.74, 95% confidence interval [CI] = 1.28 to 2.35; P < .001). A similar effect was seen for secondary outcomes (HR of treatment failure = 1.79, 95% CI = 1.15 to 2.78; P = .009). No evidence of publication bias was detected.

CONCLUSION

In clinical trials, RT protocol deviations are associated with increased risks of treatment failure and overall mortality.

Redesigning radiotherapy quality assurance: opportunities to develop an efficient, evidence-based system to support clinical trials--report of the National Cancer Institute Work Group on Radiotherapy Quality Assurance

PURPOSE

In the context of national calls for reorganizing cancer clinical trials, the National Cancer Institute sponsored a 2-day workshop to examine challenges and opportunities for optimizing radiotherapy quality assurance (QA) in clinical trial design.

METHODS AND MATERIALS

Participants reviewed the current processes of clinical trial QA and noted the QA challenges presented by advanced technologies. The lessons learned from the radiotherapy QA programs of recent trials were discussed in detail. Four potential opportunities for optimizing radiotherapy QA were explored, including the use of normal tissue toxicity and tumor control metrics, biomarkers of radiation toxicity, new radiotherapy modalities such as proton beam therapy, and the international harmonization of clinical trial QA.

RESULTS

Four recommendations were made: (1) to develop a tiered (and more efficient) system for radiotherapy QA and tailor the intensity of QA to the clinical trial objectives (tiers include general credentialing, trial-specific credentialing, and individual case review); (2) to establish a case QA repository; (3) to develop an evidence base for clinical trial QA and introduce innovative prospective trial designs to evaluate radiotherapy QA in clinical trials; and (4) to explore the feasibility of consolidating clinical trial QA in the United States.

CONCLUSION

Radiotherapy QA can affect clinical trial accrual, cost, outcomes, and generalizability. To achieve maximum benefit, QA programs must become more efficient and evidence-based.

Radiotherapy quality assurance review for a multi-center randomized trial of locally advanced esophageal cancer: the Japan Clinical Oncology Group (JCOG) trial 0303

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the radiotherapy (RT) quality assurance (QA) for JCOG 0303.

METHODS AND MATERIALS

JCOG 0303 was a multi-center phase II/III trial that compared two types of chemotherapy administered concomitantly with RT for locally advanced esophageal cancer. RT requirements included a total dose of 60 Gy in 30 fractions and CTV with a 2-cm margin cranio-caudally to the primary tumor. The QA assessment was given as per protocol (PP), deviation acceptable (DA), violation unacceptable (VU), and incomplete/not evaluable following predefined criteria for quality parameters.

RESULTS

A total of 142 cases were accrued. After excluding 36 incomplete/not evaluable, 106 (75%) were fully evaluable for RT quality review. Of these 106, there were 4 VU (4%) and overall RT compliance (PP + DA) was 96%. Comparing the incidence of VU based on the numbers enrolled by institution, the highest quarter of enrollment (≥7 cases) had no VU, while all VU (4; 11%) were from institutions enrolling <7 patients.

CONCLUSIONS

The results of the RTQA assessment for JCOG 0303 were sufficient to provide reliable results. Additional improvements will be needed for institutions with low accrual rates.

Implications of comparative effectiveness research for radiation oncology

PURPOSE

The essence of comparative effectiveness research (CER) is to understand what health interventions work, for which patients, and under what conditions. The objective of this article is to introduce the relative strengths and weaknesses of several forms of evidence to illustrate the potential for CER evidence generation within radiation oncology.

METHODS

We introduce the underlying concepts of effectiveness and efficacy. We describe the design of traditional explanatory randomized trials (RCTs). We introduce the rationale, strengths, and weaknesses of several alternative study designs for comparative effectiveness, including pragmatic clinical trials, adaptive trials, and observational (nonrandomized) studies.

RESULTS

Explanatory RCTs are designed to assess the efficacy of an intervention while achieving a high degree of internal validity. Pragmatic clinical trials (PCTs) are prospective studies performed in typical, real-world clinical practice settings. The emphasis of PCTs is to maintain a degree of internal validity while also maximizing external validity. Adaptive trials can be modified at interim stages using existing or evolving evidence in the course of a trial, which may allow trials to maintain clinical relevance by studying current treatments. Observational data are becoming increasingly important, given substantial funding for clinical registries and greater availability of electronic medical records and claims databases, but need to address well-known limitations such as selection bias.

CONCLUSION

With the rapid proliferation of new and evolving radiotherapy technologies, it is incumbent upon our field to invest in building the evidence base for radiotherapy CER and to actively participate in current initiatives for generating comparative evidence.

IAEA's role in the global management of cancer-focus on upgrading radiotherapy services

The International Atomic Energy Agency (IAEA) is an intergovernmental organization composed by 138 Member States within the United Nations. It has a mandate to seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world. Within the IAEA structure, the Division of Human Health contributes to the enhancement of the capabilities in Member States to address needs related to prevention, diagnosis and treatment of health problems through the development and application of nuclear and radiation techniques within a framework of quality assurance. In view of the increasing cancer incidence rates in developing countries the activities in improving management of cancer have become increasingly important. This review will outline the IAEA's role in cancer management focusing on activities related to improving radiotherapy worldwide.

Opening the black box of cancer surgery quality: WebSMR and the Alberta experience

A web-based synoptic operative report, the WebSMR (Surgical Medical Record), was developed to define and improve the quality of cancer surgery. Surgeons accurately record the essential steps of an operation including important decision-making in an analyzable format. Outcomes can be reviewed with provincial aggregates for quality improvement and maintenance of certification. Future synoptic pathology and follow-up templates will open the "black box" of surgical processes to define quality indicators for the improvement of cancer outcomes.

Profile of European radiotherapy departments contributing to the EORTC Radiation Oncology Group (ROG) in the 21st century

PURPOSE

Since 1982, the Radiation Oncology Group of the EORTC (EORTC ROG) has pursued an extensive Quality Assurance (QA) program involving all centres actively participating in its clinical research. The first step is the evaluation of the structure and of the human, technical and organisational resources of the centres, to assess their ability to comply with the current requirements for high-tech radiotherapy (RT).

MATERIALS AND METHODS

A facility questionnaire (FQ) was developed in 1989 and adapted over the years to match the evolution of RT techniques. We report on the contents of the current FQ that was completed online by 98 active EORTC ROG member institutions from 19 countries, between December 2005 and October 2007.

RESULTS

Similar to the data collected previously, large variations in equipment, staffing and workload between centres remain. Currently only 15 centres still use a Cobalt unit. All centres perform 3D Conformal RT, 79% of them can perform IMRT and 54% are able to deliver stereotactic RT. An external reference dosimetry audit (ERDA) was performed in 88% of the centres for photons and in 73% for electrons, but it was recent (<2 years) in only 74% and 60%, respectively.

CONCLUSION

The use of the FQ helps maintain the minimum quality requirements within the EORTC ROG network: recommendations are made on the basis of the analysis of its results. The present analysis shows that modern RT techniques are widely implemented in the clinic but also that ERDA should be performed more frequently. Repeated assessment using the FQ is warranted to document the future evolution of the EORTC ROG institutions.

EORTC 22972-26991/MRC BR10 trial: fractionated stereotactic boost following conventional radiotherapy of high grade gliomas. Clinical and quality-assurance results of the stereotactic boost arm

BACKGROUND AND PURPOSE

The EORTC trial No. 22972 investigated the role of an additional fractionated stereotactic boost (fSRT) to conventional radiotherapy for patients with high grade gliomas. A quality-assurance (QA) programme was run in conjunction with the study and was the first within the EORTC addressing the quality of a supposedly highly accurate treatment technique such as stereotactic radiotherapy. A second aim was to investigate a possible relation between the clinical results of the stereotactic boost arm and the results of the QA.

MATERIALS AND METHODS

The trial was closed in 2001 due to low accrual. In total, 25 patients were randomized: 14 into the experimental arm and 11 into the control arm. Six centres randomized patients, 8 centres had completed the dummy run (DR) for the stereotactic boost part. All participating centres (9) were asked to complete a quality-assurance questionnaire. The DR consisted of treatment planning according to the guidelines of the protocol on 3 different tumour volumes drawn on CT images of a humanized phantom. The SRT technique to be used was evaluated by the questionnaire. Clinical data from patients recruited to the boost arm from 6 participating centres were analysed.

RESULTS

There was a full compliance to the protocol requirements for 5 centres. Major and minor deviations in conformality were observed for 2 and 3 centres, respectively. Of the 8 centres which completed the DR, one centre did not comply with the requirements of stereotactic radiotherapy concerning accuracy, dosimetry and planning. Median follow-up and median overall survival were 39.2 and 21.4 months, respectively. Acute and late toxicities of the stereotactic boost were low. One radiation necrosis was seen for a patient who has not received the SRT boost. Three reported serious adverse events were all seizures and probably therapy-related.

CONCLUSIONS

Overall compliance was good but not ideal from the point of view of this highly precise radiation technique. Survival in the subgroup of patients with small volume disease was encouraging, but the study does not provide sufficient information about the potential value of fSRT boost in patients with malignant glioma.Toxicity due to an additional stereotactic boost of 20 Gy in 4 fractions was low and may be considered as a safe treatment option for patients with small tumours.

Randomized controlled trials in health technology assessment: overkill or overdue?

Evidence-based medicine has become a cornerstone in the development of radiation oncology and the randomized controlled phase III trial remains the gold standard for assessing differential benefits in clinical outcome between therapies. Health technologies aimed at improving treatment quality should primarily be tested using process measures or operational characteristics, the reason being that the sensitivity and specificity of clinical outcome is low for detecting quality improvements. The ongoing discussion of the relative merits of intensity modulated photon versus proton radiotherapy is used to illustrate these concepts. Concerns over clinical and individual equipoise as well as the potential limitations of health economics considerations in this setting are also discussed. Working in a technology and science based medical discipline, radiation oncology researchers need to further develop methodology for critical assessment of health technologies as a complement to randomized controlled trials.

Preventing or reducing late side effects of radiation therapy: radiobiology meets molecular pathology

Radiation therapy has curative or palliative potential in roughly half of all incident solid tumours, and offers organ and function preservation in most cases. Unfortunately, early and late toxicity limits the deliverable intensity of radiotherapy, and might affect the long-term health-related quality of life of the patient. Recent progress in molecular pathology and normal-tissue radiobiology has improved the mechanistic understanding of late normal-tissue effects and shifted the focus from initial-damage induction to damage recognition and tissue remodelling. This stimulates research into new pharmacological strategies for preventing or reducing the side effects of radiation therapy.

Molecular markers predicting radiotherapy response: report and recommendations from an International Atomic Energy Agency technical meeting

PURPOSE

There is increasing interest in radiogenomics and the characterization of molecular profiles that predict normal tissue and tumor radioresponse. A meeting in Amsterdam was organized by the International Atomic Energy Agency to discuss this topic on an international basis.

METHODS AND MATERIALS

This report is not completely exhaustive, but highlights some of the ongoing studies and new initiatives being carried out worldwide in the banking of tumor and normal tissue samples underpinning the development of molecular marker profiles for predicting patient response to radiotherapy. It is generally considered that these profiles will more accurately define individual or group radiosensitivities compared with the nondefinitive findings from the previous era of cellular-based techniques. However, so far there are only a few robust reports of molecular markers predicting normal tissue or tumor response.

RESULTS

Many centers in different countries have initiated tissue and tumor banks to store samples from clinical trials for future molecular profiling analysis, to identify profiles that predict for radiotherapy response. The European Society for Therapeutic Radiology and Oncology GENEtic pathways for the Prediction of the effects of Irradiation (GENEPI) project, to store, document, and analyze sample characteristics vs. response, is the most comprehensive in this regard.

CONCLUSIONS

The next 5-10 years are likely to see the results of these and other correlative studies, and promising associations of profiles with response should be validated in larger definitive trials.

The quality assurance programme of the Radiotherapy Group of the European Organisation for Research and Treatment of Cancer: past, present and future

As early as in 1982, the European Organisation for Research and Treatment of Cancer Radiotherapy Group established a quality assurance programme. In the course of 20 years, quality assurance procedures have become a vast and important part of the activities of the group. Today, the membership committee uses standard procedures based on minimal requirements to evaluate current members and new membership applications. Moreover, for every new trial, specific quality assurance procedures are an integral part of the preparation of the protocol and executed under the responsibility of the study coordinator. With the growing complexity of the radiotherapy techniques used in the framework of the more recent trials, quality assurance procedures have also become more complex including trial specific phantom based measurements. Future ways to evaluate all steps of the radiotherapy process using a common platform connecting all users with the internet are currently under development.

Quality assurance of surgery in gastric and rectal cancer

Multimodality and quality controlled treatment result in improved treatment outcome in patients with solid tumours. Quality assurance focuses on identifying and reducing variations in treatment strategy. Treatment outcome is subsequently improved through the introduction of programs that reduce treatment variations to an acceptable level and implement standardised treatment. In chemotherapy and radiotherapy, such programmes have been introduced successfully. In surgery however, there has been little attention for quality assurance so far. Surgery is the mainstay in the treatment of patients with gastric and rectal cancer. In gastric cancer, the extent of surgery is continuously being debated. In Japan, extended lymph node dissection is favoured whereas in the West this type of surgery is not routinely performed with two large European trials concluding that there is no survival benefit from regional lymph node clearance. Post-operative chemoradiation is part of the standard treatment in the United States, although its role in combination with adequate surgery has not been established yet. These global differences in treatment policy clearly relate to the extent and quality of surgical treatment. As for gastric cancer, surgical treatment of rectal cancer patients determines patient's prognosis to a large extent. With the introduction of total mesorectal excision, local control and survival have improved substantially. Most rectal cancer patients receive adjuvant treatment, either pre- or post-operatively. The efficacy of many adjuvant treatment regimens has been investigated in combination with conventional suboptimal surgery. Traditional indications of adjuvant treatment might have to be re-examined, considering the substantial changes in surgical practise. Quality assurance programs enable the introduction of standardised and quality controlled surgery. Promising adjuvant regimens should be investigated in combination with optimal surgery.

Clinical trials update of the European Organization for Research and Treatment of Cancer Breast Cancer Group

The present clinical trial update consists of a review of two of eight current studies (the 10981-22023 AMAROS trial and the 10994 p53 trial) of the European Organization for Research and Treatment of Cancer Breast Cancer Group, as well as a preview of the MIND-ACT trial. The AMAROS trial is designed to prove equivalent local/regional control for patients with proven axillary lymph node metastasis by sentinel node biopsy if treated with axillary radiotherapy instead of axillary lymph node dissection, with reduced morbidity. The p53 trial started to assess the potential predictive value of p53 using a functional assay in yeast in patients with locally advanced/inflammatory or large operable breast cancer prospectively randomised to a taxane regimen versus a nontaxane regimen.

High-tech in radiation oncology: should there be a ceiling?

PURPOSE

To analyze some of the limitations to improvement of the outcome of radiotherapy (RT) expected from the introduction of sophisticated treatment planning and delivery technology.

METHODS AND MATERIALS

Several recent examples from the literature were analyzed in some detail. Mathematical modeling techniques were used to assess the likely clinical impact of new technologies or biologic principles. The findings of recent randomized controlled trials of RT for prostate, breast, and rectal cancer were analyzed from the perspective of cost-effectiveness and therapeutic gain.

RESULTS

The main findings of the analyses may be summarized as follows. Dosimetric precision should aim for a <2% patient-to-patient variability in the delivered dose. Imprecision in clinical target volume definition remains an obstacle for high-precision RT. Functional imaging and novel biologic assays may facilitate a move from a clinical target volume to the real target volume. Improved target volume coverage is mainly important if RT has high effectiveness. Radiation oncology is increasingly becoming evidence based. However, there is still a long way to go. Hypofractionation in adjuvant RT for breast cancer may represent a favorable balance between cost and benefit. Treatment complications are potentially associated with both suffering and high cost. The identification of high-risk patients would improve the cost-effectiveness of high-tech RT aimed at avoiding complications. Conformal RT may allow the introduction of hypofractionation, which, again, could potentially save resources. With improvement in surgery and more screening-detected cancer cases, the number needed to treat increases, and this will directly affect the cost-effectiveness of high-tech RT unless efficient patient selection can be developed.

CONCLUSION

Sustained technological refinement is only likely to be cost-effective if the clinical and biologic understanding of patient-to-patient variability in the risk of specific types of failure and the optimal multimodality approach to handle these risks is developed at the same time. Mathematical modeling together with methods from health technology assessment and health economics are useful complements to standard methods from evidence-based medicine. Progress in functional imaging and in basic and clinical cancer biology is likely to provide the tools required for individualized risk-adapted RT.

Quality assurance of axillary radiotherapy in the EORTC AMAROS trial 10981/22023: the dummy run

PURPOSE

To assess and if needed improve the compliance of participating institutions to the radiotherapy guidelines of the EORTC AMAROS trial 10981/22023 comparing axillary radiotherapy to axillary surgery in sentinel node positive patients with early stage breast cancer.

MATERIALS AND METHODS

A transverse contour and a frontal view radiograph of the axillary region of a 'dummy' patient were sent to all institutions intending to participate in the trial with the request to produce a radiotherapy treatment plan according to the protocol guidelines. Additional information on dose prescription, the treatment technique and field matching with breast fields and internal mammary lymph node fields was requested in a questionnaire.

RESULTS

Eighteen institutions have performed the dummy run. At first assessment, the dose was not specified according to the protocol in seven cases, while two institutions did not comply with the dose prescription of 50 Gy in 25 fractions. Dose heterogeneity was over 20% in 10 institutions, caused by the use of a two-field technique in eight cases. Ten institutions did not apply special techniques to obtain non-overlapping match planes. In 10 cases, one or more field borders or blocks were positioned incorrectly. Following recommendations from the quality assurance committee given to the participating institutions on an individual basis, 10 institutions adapted their technique. Thereafter, 16 institutions could be accepted for trial participation.

CONCLUSIONS

A number of potential protocol deviations were found at first assessment. Since recommendations led to a large number of adaptations by the participants, a considerable improvement in protocol compliance and inter-institutional consistency was achieved.

Quality assurance in clinical trials

From the literature that was initially searched by electronic databases using the keywords quality, quality control and quality assurance in combination with clinical trials, surgery, pathology, radiotherapy, chemotherapy and data management, a comprehensive review is given on what quality assurance means, the various methods used for quality assurance in different aspects of clinical trials and the impact of this quality assurance on outcome and every day practice.

The Quality Assurance programme of the Radiotherapy Group of the European Organization for Research and Treatment of Cancer (EORTC): a critical appraisal of 20 years of continuous efforts

In 1982, the European Organization for Research and Treatment of Cancer (EORTC) Radiotherapy Group established the Quality Assurance (QA) programme. During the past 20 years, QA procedures have become a major part of the activities of the group. The methodology and steps of the QA programme over the past 20 years are briefly described. Problems and conclusions arising from the results of the long-lasting QA programme in the EORTC radiotherapy group are discussed and emphasised. The EORTC radiotherapy group continues to lead QA in the European radiotherapy community. Future challenges and perspectives are proposed.

Quality assurance in radiotherapy

In 1999, the European Organisation for Research and Treatment of Cancer (EORTC), being a European pioneer in the field of cancer research as well as in quality assurance (QA), launched an Emmanuel van der Schueren fellowship for QA in radiotherapy. In this paper, the work that has been done during the first E. van der Schueren fellowship is reported, focusing on four phase III EORTC clinical trials: 22921 for rectal cancer, 22961 and 22991 for prostate cancer and 22922 for breast cancer. A historical review of the QA programme of the EORTC Radiotherapy group during the past 20 years is included.

Current calibration, treatment, and treatment planning techniques among institutions participating in the Children's Oncology Group

PURPOSE

To report current technology implementation, radiation therapy physics and treatment planning practices, and results of treatment planning exercises among 261 institutions belonging to the Children's Oncology Group (COG).

METHODS AND MATERIALS

The Radiation Therapy Committee of the newly formed COG mandated that each institution demonstrate basic physics and treatment planning abilities by satisfactorily completing a questionnaire and four treatment planning exercises designed by the Quality Assurance Review Center. The planning cases are (1) a maxillary sinus target volume (for two-dimensional planning), (2) a Hodgkin's disease mantle field (for irregular-field and off-axis dose calculations), (3) a central axis blocked case, and (4) a craniospinal irradiation case. The questionnaire and treatment plans were submitted (as of 1/30/02) by 243 institutions and completed satisfactorily by 233. Data from this questionnaire and analyses of the treatment plans with monitor unit calculations are presented.

RESULTS

Of the 243 clinics responding, 54% use multileaf collimators routinely, 94% use asymmetric jaws routinely, and 13% use dynamic wedges. Nearly all institutions calibrate their linear accelerators following American Association of Physicists in Medicine protocols, currently 16% with TG-51 and 81% with TG-21 protocol. Treatment planning systems are relied on very heavily for all calculations, including monitor units. Techniques and results of each of the treatment planning exercises are presented.

CONCLUSIONS

Together, these data provide a unique compilation of current (2001) radiation therapy practices in institutions treating pediatric patients. Overall, the COG facilities have the equipment and the personnel to perform high-quality radiation therapy. With ongoing quality assurance review, radiation therapy compliance with COG protocols should be high.

The importance of quality assurance in surgical oncology

AIMS

The aims were to review the existing methods of quality assurance in surgical oncology and to determine a relationship between surgery-related factors and the variety in outcomes in the treatment of solid cancers.

METHODS

The literature was reviewed by searching Medline and Cancerlit databases.

RESULTS

Wide variations were found in virtually all tumour types. Clear evidence was found that an improvement in the quality of the surgical procedure could have major implications for the prognosis and quality of life of cancer patients.

CONCLUSIONS

These findings emphasize the need for strict quality control procedures in surgical oncology and might imply a considerable change in cancer treatment strategies, because the routine use of adjuvant therapies could be questioned.

Quality assurance of the EORTC trial 22911. A phase III study of post-operative external radiotherapy in pathological stage T3N0 prostatic carcinoma: the dummy run

INTRODUCTION

A dry run of a clinical trial (EORTC 22911) is presented in which 12 centres have participated. These are the centres which have contributed the largest number of patients to the trial.

MATERIAL AND METHODS

Each participating centre received data from a suitable patient. Investigators were asked to plan and 'treat' the patient according to the protocol guidelines and return the data for evaluation of compliance.

RESULTS

The results show that compliance to the protocol guidelines was generally good. There were a few minor deviations in the dose and fractionation schedule, in the volume reduction for the booster dose and in the dose prescription point. None of these deviations will affect the outcome of the study. The most important observation is the large inter-centre variation in target volumes.

CONCLUSIONS

The results of this study underlines the need for a strict definition of the target volume and the adoption of the ICRU 50 recommendations in future protocols.