Japanese Journal of Clinical Oncology 32:493-496 (2002)
© 2002 Foundation for Promotion of Cancer Research
Editorial |
Quality Assurance Activities in Radiotherapy
Division of Radiation Oncology, National Cancer Center Hospital, Tokyo, Japan
Necessity and Measures of Quality Assurance in Radiotherapy
The radiotherapy performed today is not uniform in quality and the end results obtained differ widely depending on the diversity of quality. As clinical study trials including radiotherapy modality have become more prevalent, the need for quality assurance (QA) in this field has emerged. In Japan, clinical trials have mainly been conducted by medical oncologists. The complication rate that medical oncologists assumed to be due to radiotherapy has become conspicuous and the necessity for QA arose.
Measures and procedures for QA in the radiation oncology field can be classified as operational aspects, physics and technical aspects and clinical aspects, according to the World Health Organization (WHO) (1). Physics aspects, techniques and operational aspects are represented by site visits and mailed thermoluminescent dosimeter (TLD) programs for dosimetric intercomparisons and follow-up of calibration procedures. Other procedures are aimed at detecting and scoring deviations from criteria defined in the protocol and are specific for clinical aspects of protocols and patients. If such deviations are found, corrective actions have to be taken for the concerned or subsequent patients. There are two components of the clinical QA program: proactive measures (dummy run) and monitoring/review measures (individual case review) (2).
1. Site visits
Site visits are necessary as a QA program, in order to ascertain the medical and radiotherapeutic environment and to check the radiation physics performance of the megavoltage equipment of each participating institution. Various procedures are included, such as intercomparison of ionization chambers, mechanical checks of equipment (megavoltage accelerator and simulator) and calculation of treatment time and monitor setting for reference cases.
2. In vivo dosimetry
The radiation dose received should be checked and evaluated, especially in international multicenter trials. For this purpose, mailed in vivo dosimetry with TLDs has been shown to be a feasible method. The TLDs are sent to institutions with a request to use them on one or several patients during one fraction according to the protocol compared with the stated (prescribed) value.
3. Dummy run procedure
The proactive clinical measures are those implemented to ensure that the protocol requirements are clearly stated and followed. A dummy case, designed to incorporate one or more critical items, is circulated to the institutions wishing to participate, asking them to provide the choices of technique that would be used in that case, following the protocol recommendations. The reports from the institutions are analyzed and independently reviewed at the central office. This is a mainly protocol-oriented test to define both the incidence and range of deviations before or at the beginning of a trial.
4. Individual case review
The monitoring/review measures involve an ongoing data review and evaluation of institutions for treatment specific parameters. The aim is to identify the quality of performance of the member institution with respect to the accrual of ineligible patients, timeliness and quality of documentation submission and compliance with protocol treatment within a few months of the protocol activation. This procedure is focused on protocol-specific issues, such as comparison between simulator films and portal films and follow-up information. A team of physicians and physicists undertakes this procedure and possible deviations are immediately discussed with the institution’s representatives.
QA ACTIVITIES IN OTHER COUNTRIES
IAEA/WHO Activities
The International Atomic Energy Agency (IAEA) undertakes diverse activities connected with the peaceful use of atomic energy and radiation. The IAEA/WHO has been performing mailed TLD audits to verify radiotherapy beams in developing countries since 1969 (3). Many institutions in Japan have been reluctant to join this activity, because of the language issue and insufficient awareness or understanding for the activity. The WHO published a book about QA in radiation therapy in 1988 (1).
QA Activities in Europe
Established in 1962, the European Organization for Research and Treatment of Cancer (EORTC) has promoted high-quality laboratory research and clinical trials in Europe. The Radiotherapy Group was established in 1975 and is one among the 21 Clinical Research Groups that EORTC now has (4,5). As early as 1982, it started a specific Europe-wide program on QA and dose intercomparison (6). The physical QA and clinical QA programs involve several measures besides auditing: mailed dosimetry with TLDs (since 1987), the dummy run system (since 1987) and individual case reviews (since 1989) as an even more patient-oriented QA method. These programs have demonstrated a decrease in major deviations of photon and electron calibrations after two successive audits at each institution.
The extensive QA activity in Europe will be modified in the near future. The European Society for Therapeutic Radiology and Oncology (ESTRO), which is also involved in the physical and clinical aspects of QA, established the European Institute for Quality Assurance in Radiotherapy (EQART) (7). The aims and services of EQART are as follows: (1) to advance quality assurance and quality control procedures; (2) to support internal QC procedures where appropriate with advice, methodology or equipment; and (3) to advise/support on the implementation of QA procedures such as in vivo dosimetry. ESTRO has also recently set up a QA network (EQUAL) to check the dose delivered on axis in reference and non-reference conditions for external radiotherapy (8). The external audits covered by the network are based on measurements made; 102 centers have been checked, corresponding to 235 beams (28 Co-60 beams and 207 X-ray beams) with mailed TLDs during the 1998 EQUAL program. Of these, about 3% of the outputs in reference conditions showed deviations outside the tolerance level(>5%). The results of the EQUAL program show the importance of a QA network in radiotherapy. The EORTC RT Group will probably join the broader European project that will be launched by the ESTRO. Protocol-specific quality control procedures such as questionnaires, individual case reviews and dummy run procedures will continue to be performed, particularly for trials investigating the most modern techniques of radiation therapy delivery.
QA Activities in the USA
The Radiological Physics Center (RPC) has been funded continuously by the National Cancer Institute (NCI) since 1968 to provide quality auditing of dosimetry practices at institutions participating in NCI cooperative clinical trials, and is continuously advised and supported by the Radiation Therapy Committee of the American Association of Physicists in Medicine (AAPM) (9). Housed at the M. D. Anderson Cancer Center since its inception, the primary responsibility of the RPC is to assure the NCI and the cooperative clinical trial groups that all participating institutions have the equipment, personnel and procedures necessary to administer radiation in doses that are clinically comparable to those of other participating institutions. The monitoring tools used include on-site dosimetry reviews; remote auditing tools including TLD, anthropomorphic phantoms and reviews of benchmark and actual protocol patient treatments.
In 1969, there were three cooperative groups, each with one protocol involving radiation therapy. Thirty-five megavoltage therapy facilities participated and the RPC was the only group identified by the NCI to monitor QA. In 1974 when 20 multidisciplinary cooperative groups with more than 200 therapy institutions participated, the NCI established six Centers of Radiological Physics (CRPs) to monitor the extension of modern diagnosis and radiotherapy to community hospitals. The cooperative group activity changed so that by 1996 there were nine cooperative groups, four quality assurance offices (QAOs) remaining and more than 1050 participating radiotherapy facilities. There has been a marked improvement in radiation dosimetry over the past three decades in part by monitoring by RPC through its auditing tools. Between 1970 and 1980, the compliance rate of ±3% for beam calibration increased from approximately 70% to 90% and currently it has improved to near 98%, for both photon and electron beam calibrations. In 2001 there were eight cooperative groups, three other QAOs and nearly 1300 radiotherapy facilities monitored by the RPC. The Southwest Oncology Group (SWOG) and other representative clinical trial groups now have their independent QA committees and measures. In addition, the Proton Working Group and the 3-D QA Center were established to monitor high-technology studies. The Image Guided Radiotherapy QA Center in St. Louis, MO, and the Resource Center for Emerging Technologies (RCET) in Gainesville, FL, are funded to establish databases of image-guided radiotherapy treatments for cooperative groups and to make the data available for evaluation.
The Radiation Therapy Oncology Group (RTOG) was organized in 1967 under the auspices of the Committee for Radiation Therapy Studies, an advisory committee to the leadership of the National Cancer Institute (NCI). Together with RPC activities, the RTOG since 1978 and the Quality Assurance Review Center (QARC) since 1980 have been active in QA in clinical radiotherapy performance reviews. The current status and future research plans of the RTOG are summarized in Volume 51, Supplement 2 of the International Journal of Radiation Oncology, Biology and Physics, 2001 (10). The SWOG conducted a randomized study of applying low-dose involved field radiation after chemotherapy in advanced Hodgkin’s disease. This showed that 56% of relapsing patients had a major radiation protocol violation and 12.5% had a minor violation (11). As the violation diminished, the clinical trial results improved accordingly.
QA GUIDELINES FOR SOPHISTICATED RADIOTHERAPY MODALITIES
In recent years, the sophistication and complexity of clinical treatment planning and treatment planning systems have increased significantly, particularly with three-dimensional (3-D) treatment planning systems and the use of conformal treatment planning and delivery techniques. This has led to the need for a comprehensive set of QA guidelines that can be applied to sophisticated clinical treatment planning. EORTC conducted another survey in 1994 aimed at identifying the progress of treatment planning and therapy equipment. A tentative profile and guidelines for minimum recommendations for European radiotherapy departments involved in clinical research was published in 1996. Task Group 53 of the AAPM RT Committee published the TG Report-53 in 1998 (12). Developing and implementing a comprehensive QA program for modern radiotherapy treatment planning is primarily an issue of individual institutions and the responsibility of the clinical radiation physicists engaged. However, this Report recommends an organizational framework for the task of creating a QA program and addresses the issues of acceptance testing and commissioning QA of both the planning system and planning process.
QA ACTIVITIES IN JAPAN
There have been very few radiation physicists and very few organizations conducting QA activities in Japan. With regard to the physical aspects of QA, only the standardized calibration of institutional dosimeters has been performed systematically. In 1976, the Japan Radiological Society established a Research Group for Standardized Calibration of Dosimeters. Its aims were to adjust the dosimeters of each institution in Japan to a primary standard or secondary standard dosimeter by bringing dosimeter probes to local centers. Thus the delivered dose can be traced in the calibration chain to the standard reference dosimeter. Four hundred institutions participated in this activity annually and it obviously raised the delivery dose to a standardized level in Japan. However, participation is voluntary for technicians in each institution. Site visit auditing for dosimetry and its intercomparison have also been done only sporadically at the time of grant funding. Since 2001, the Ministry of Health, Labor and Welfare has been promoting research with a grant for ‘The improvement of prognosis of cancer patients through radiotherapy QA and technical innovations,’ the principal investigator being H. Ikeda, Head of the Radiotherapy Division, National Cancer Center Hospital. He and his colleagues intend to conduct both physical QA and clinical QA through site visits and various other QA measures. For physical and technical QA they conduct dosimetry site visits and mailing of glass-rod dosimeters. For clinical QA they recently commenced aiding in QA in specific clinical trials including radiotherapy, in close cooperation with the Radiotherapy Committee of the Japan Clinical Oncology Group (JCOG) (13). Since body stereotactic radiotherapy was approved by the Ministry of Health, Labor and Welfare as ‘High Technology Medicine’ in 2000, some members involved in the QA study of MHLW issued a declaration statement for institutions and vendors regarding the conduct of intensity-modulated radiotherapy (IMRT) in Japan in 2002. They were worried about the paucity of QA and recommend that institutions keep the equipment, personnel, procedures and data updated and of satisfactory precision.
Patterns of Care Study (PCS) was the first in Japan to conduct an auditing method in clinical radiation oncology and probably the first in the overall clinical oncology field. Professor T. Inoue and his colleagues throughout Japan conducted chart reviews and succeeded in demonstrating the characteristics of institutions according to the structure (14,15). Using the double cluster sampling method for institutions and for patients, the PCS collects detailed information on the process and outcome of patients with cancer where radiation therapy plays an important role. They analyzed the structure of radiation oncology from the first-stage sampling based on the stratification of the institutions. Using this sampling, they calculated a national average which represents the national practice regarding the process and outcome for cancer patients from the collected resources. The PCS can monitor the changes in national practice for specific disease sites every 4–5 years and give feedback on the structural problem to the oncology community. The PCS can also monitor the distribution of positive results from clinical trials, and provide information such as the prediction of the number of eligible patients in clinical trials nationwide and the quality of practice of participating institutions. Further, Professor Inoue and his colleagues intend to undertake a comparison of patterns of care in the USA and Japan.
Submissions of papers to Western journals are increasing and papers are all from A1 institutions. In B2 institutions where the annual patient accrual is below 120, the PCS revealed clearly the character of the institution as managed with few staff, insufficient application of beam energy to diseases and sites and little accumulation of clinical data. Since April 2002, the social insurance system in Japan has decided to pay only 70% of the standard treatment fee for an institution that treats fewer than 100 patients annually. The PCS is an important survey nationwide, and should be driven by national resources as a complementary study for prospective controlled studies for evidence-based medicine. This auditing method is acceptable in other fields of clinical oncology.
CONCLUSION
The radiotherapy performed today is not uniform in quality and the end results obtained differ widely depending on the diversity of quality. An overall QA program has an impact not only on the treatment received by patients enrolled in clinical trials, but also on the quality of treatment administered to all patients treated at an institution. Western countries have a more than 30-year history of QA activities. In Japan there are very few organizations that conduct QA activities in radiation oncology. However, the QA study group of MHLW will promote this area, in close collaboration with the Radiotherapy Quality Assurance Center (RTQAC), a subsidiary of the Radiotherapy Committee, JCOG. The PCS is another measure of QA and is also acceptable in other fields of clinical oncology.
REFERENCES
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