British Journal of Radiology (2006) 79, 116-122
© 2006 British Institute of Radiology
doi: 10.1259/bjr/27372198
An audit of imaging test utilization for the management of lymphoma in an oncology hospital: implications for resource planning?
A Schwartz, BSc
M K Gospodarowicz, MD
K Khalili, MD
M Pintilie, MSc
S Goddard, BSc
A Keller, MD
and
R W Tsang, MD
University of Toronto, Princess Margaret Hospital, University Health Network, 610 University Avenue, Toronto, Ontario, M5G 2M9 Canada
Correspondence: Dr Richard W Tsang
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Abstract
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The purpose of this study was to assist with resource planning by examining the pattern of physician utilization of imaging procedures for lymphoma patients in a dedicated oncology hospital. The proportion of imaging tests ordered for routine follow up with no specific clinical indication was quantified, with specific attention to CT scans. A 3-month audit was performed. The reasons for ordering all imaging procedures (X-rays, CT scans, ultrasound, nuclear scan and MRI) were determined through a retrospective chart review. 411 lymphoma patients had 686 assessments (sets of imaging tests) and 981 procedures (individual imaging tests). Most procedures were CT scans (52%) and chest radiographs (30%). The most common reasons for ordering imaging were assessing response (23%), and investigating new symptoms (19%). Routine follow up constituted 21% of the assessments (142/686), and of these, 82% were chest radiographs (116/142), while 24% (34/142) were CT scans. With analysis restricted to CT scans (296 assessments in 248 patients), the most common reason for ordering CT scans were response evaluation (40%), and suspicion of recurrence and/or new symptom (23%). Follow-up CT scans done with no clinical indication comprised 8% (25/296) of all CT assessments. Staging CT scans were under-represented at 6% of all assessments. Imaging with CT scans for follow up of asymptomatic patients is infrequent. However, scans done for staging new lymphoma patients were unexpectedly low in frequency, due to scans done elsewhere prior to referral. This analysis uncovered utilization patterns, helped resource planning and provided data to reduce unnecessary imaging procedures.
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Introduction
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Lymphoma clinicians rely heavily on imaging techniques to determine the stage of disease at initial presentation, to assess the response to treatment and to follow the disease over time [1]. CT scans remain the standard for evaluation of nodal disease [2], while MRI gives additional information for some extranodal sites. Gallium scans and/or 18FDG-PET scans are also useful tools in the staging and follow-up where they help to distinguish residual fibrotic mass from viable lymphoma [3, 4]. After treatment has been completed and providing a complete remission has been achieved, the goal of follow-up investigations is to identify recurrent disease before symptoms develop [5]. However, routine CT imaging for follow up has not been shown to be cost-effective, as investigation of symptoms is the most cited reason for finding recurrent disease [6–13]. Several studies documented that only 5–9% of relapses were imaging-detected before the development of symptoms [5, 11, 13].
At a dedicated oncology hospital, the policy for lymphoma patients has not been to perform routine CT imaging for follow up of asymptomatic patients beyond the attainment of complete remission of disease. Taking a chest radiograph has been left to the discretion of the attending physician. This is in agreement with published studies that suggested CT scan should be performed according to clinical indications, not strictly as routine actions [8, 10]. Edelman et al also proposed that "eliminating unnecessary testing would decrease the risk of further physical and psychological harm from the inevitable occurrence of false-positive tests" [9]. The subject of whether clinicians are optimally utilizing the available imaging modalities has been seldom studied [10]. This is particularly important in an environment of limited resources, as there is usually a waiting list to access certain imaging procedures such as CT and MRI scans. Concerns were expressed by the imaging department that the lymphoma group may be ordering an excessive number of scans unnecessarily for routine follow ups, hence making the resource less available for staging or other urgent reasons in a timely fashion. Therefore, in this study, the pattern of physician utilization of imaging investigations in the management of lymphoma was examined. The goal was to ascertain the indications for each imaging examination, for example: staging, evaluating response to treatment, suspected or confirmed recurrence, and routine follow-up monitoring. The aim was to determine the relative frequencies of the utilization of various imaging modalities, for follow-up monitoring versus for staging and response assessment. There was specific interest in determining if CT scans were often requested for routine follow-up in asymptomatic patients, to understand if this resource was overutilized, possibly at the expense of patients who may require the scans more urgently for assessment of disease.
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Methods
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A 3-month audit of imaging procedures performed on lymphoma patients from January 1st to March 31st 2003 at a dedicated oncology hospital was performed. The Research and Ethics Board of the hospital approved the study. Patients were identified from the Imaging Department database and all were listed with a diagnosis of lymphoma. For this study, patients with a diagnosis of myeloma, leukaemia (acute and chronic) and benign haematological conditions were excluded. A record of all plain radiographs, CT scans, MRI, gallium, mammograms, bone scans, and ultrasound examinations were kept for the 3-month period. Patient demographics, disease extent, and treatment information were collected on each patient through a chart review. Details of histology, Ann Arbor stage, treatment, and response were abstracted. The oncologist responsible for each patient was recorded.
For the purpose of this study, a "procedure" was considered a single imaging examination. For example, CT thorax, CT abdomen/pelvis, gallium scan and ultrasound were each counted as separate procedures (total: four procedures). An "assessment" was defined as a set of imaging examinations all carried out over a 2 weeks period and requested for the same purpose. By definition, CT thorax, CT abdomen/pelvis, gallium scan and ultrasound, if all done for staging, were counted as one assessment. A "new" patient in this study was a patient referred with a new diagnosis of lymphoma. Imaging tests performed up to 6 months after completion of definitive therapy were counted as performed for a "new patient". An "old" patient was defined as one who had had imaging performed more than 6 months after completing initial therapy. A patient with a previous diagnosis of lymphoma, but referred for management of relapse beyond 6 months of completing initial therapy was considered an "old" patient. If a patient was under observation, for example in asymptomatic advanced stage follicular lymphoma, and the observation period lasted for more than 6 months from the time of referral, they would then be considered an "old" patient as well. The purpose of this distinction was to separate imaging utilization between patients referred with a new diagnosis of lymphoma for management (new), and those beyond the stage of initial treatment and attainment of complete remission (old).
The indication for ordering each assessment was determined based on the physician's clinical notes in the medical record. Reasons for ordering imaging assessments were categorized into: staging, response assessment, evaluation of residual disease, investigation of new symptoms, suspicion of recurrence, routine follow-up with no specific clinical indication, procedure related assessments such as biopsies, assessments mandated by study protocol, assessments performed for unrelated medical problems, assessments recommended by radiologists, surveillance for a secondary malignancy and assessments done for treatment complications. Questionable cases were reviewed by additional clinicians and a reason assigned by consensus.
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Results
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411 patients were included in the study. Patient characteristics are shown in Table 1
. The most common non-Hodgkin's lymphoma histologies were diffuse large B-cell lymphoma (22%), follicular lymphoma (20%), and others (23%). The initial diagnosis date is shown in Figure 1. 50% of the patients were diagnosed before 2000, and 24% in 2002, which had the greatest proportion of patients diagnosed in a single year.
The group of 411 patients generated a total of 686 imaging assessments and 981 procedures within the 3-month period. Of these assessments, 25% (171/686) were for "new" patients and 75% (515/686) were for "old" patients. Most patients had one assessment (72%, Figure 2), while the majority of assessments (70.1%) consisted of one procedure (Figure 3). The total number of procedures performed per patient within the 3-month period is shown in Figure 4. CT scans constituted 52% of imaging procedures performed on lymphoma patients, followed by chest radiographs (30%), while others account for <10% each (Figure 5).
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Figure 5. Imaging procedures performed during the 3-month study on lymphoma patients. This graph shows the percentage of procedures that each imaging examination comprises.
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The most common indications for assessments were response assessment (23%), investigation of new symptoms (19%), and routine follow-up (21%) (Figure 6). Staging constituted only 4% of assessments (Figure 6). Other indications for scans accounted for 18% of assessments, but could be broken down into procedure related (5%), study protocol (4%), unrelated medical problem (4%), recommended by radiologist (3%), surveillance for a secondary malignancy (1%) and investigation of treatment complications (1%). A comparison of the indications for assessments between "new" and "old" patients is shown in Figure 7. The largest differences between the new and old patients are in staging with a 14.2% difference, response assessment with a 25.6% difference and routine follow-up with a 26% difference.
Imaging requested for routine follow-up
Within the 3-month period, 140 patients had routine follow-up imaging with no specific clinical indication. These patients received 142 assessments and 152 procedures, which comprised 16% of all procedures. The types of imaging procedures are shown in Table 2. Chest radiographs accounted for the majority (82%) The follow-up chest radiographs constituted 116 assessments of 295 performed over the 3-month period (39% of chest radiograph assessments).
Utilization of CT scans
CT scans were performed on 248 patients. These patients received 296 assessments and 513 procedures (Table 3). 30% of these patients were "new" and 70% were "old". Over the 3-month period, the majority of patients (85%) received one CT assessment (Table 3), but each assessment may involve 1–3 CT procedures (Table 4).
The indications for CT scans included 40% for response assessment, 13% for suspicion of recurrence, 11% for residual disease, 10% for investigation of new symptoms, 8% for routine follow up, 6% for staging and 12% for other reasons (Figure 8). When comparing the indications for CT between "new" and "old" patients, the largest differences were 38% for response assessment, and 17% for staging, and a difference of 17% for suspicion of recurrence and 12% for routine follow up (Figure 9). All the routine follow up CT assessments (n = 25) were done for "old" patients, and accounted for 12.3% of the CT scan assessments done for "old" patients. Medical oncologists requested 92% (23/25) and radiation oncologists requested 8% (2/25) of the routine follow up CT scans. Of the follow-up CT scans, 72% (18/25) were in patients diagnosed in 2000–2003.
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Discussion
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At the time when this study was initiated, there were two main concerns at the hospital regarding the utilization of imaging resources by the lymphoma group. A first concern for clinicians was that scans ordered as staging investigations might overwhelm the imaging resource, as it is known that all new patients must be staged with imaging examinations [14], specifically CT scans of head and neck, thorax, abdomen and pelvis [1]. The results showed that staging accounts for only 4% of all the imaging assessments, and for an analysis restricted to CT scans it was 6% of assessments. The differences between the "new" patients and "old" patients showed an expected trend of "new" patients receiving more assessments for staging and evaluation of response. However, even for "new" patients the utilization of imaging for staging is low, and since all patients are staged with imaging, this implied that the majority had initial imaging performed prior to referral. The audit was conducted at a tertiary oncology hospital, with many patients seen by external specialists and hence were fully assessed with imaging procedures prior to their referral. This is especially true for patients with stage I–II disease referred for radiation therapy. The Radiation Oncology Department saw 88 new patients in the same 3-month period of this study. Of these patients, 40% (35/88) received radiation therapy. Only 26% (9/35) of those who received radiation therapy were staged with imaging procedures at the study hospital and included in the audit. This infers that 74% of new patients who received radiation therapy had staging scans performed elsewhere prior to their referral and were not even included in this study. "Old" patients had proportionately more assessments for residual disease, suspicion of recurrence and routine follow up. These trends are easily understood by the definition used for "new" patients, as those actively receiving their primary treatment, or those within 6 months of treatment completion when scans are performed to document response.
A second concern stems from the waiting time for accessing CT scans, which was up to 2–3 weeks from the time of the request at the time this study was conducted. It was important to determine if there was a disproportionately large number of patients being scanned for routine follow-up with no specific clinical indication, thereby making the resource less available to requests for more urgent reasons. It was anticipated that a reduction in routine follow-up scans would free up resources and therefore reduce the waiting time for scans. In this study, imaging assessments performed as part of routine follow-up with no discernable clinical indication accounted for 21% of the total assessments and 16% of the total procedures. Follow-up represents a large proportion of assessments when all imaging procedures are grouped together, but chest radiographs account for the majority of follow-up procedures (82%), and only 24% consisted of CT scan procedures. A chest radiograph is less costly and more widely available compared with a CT scan [8, 9, 11, 15, 16]. Indeed, for routine follow-up, chest radiographs were more frequently ordered by clinicians compared with CT scans in this study, but it is less sensitive compared with a thorax CT scan. Studies have found that CT scans are minimally effective for follow-up in identifying relapses [1, 10, 17] as relapses are most often detected by patients developing disease-related symptoms [6–9, 11–13, 18]. Therefore, this implies that the practice of ordering routine chest radiographs has questionable clinical benefit, although one study did suggest a role in following Hodgkin's disease in the first 3 years after treatment [12]. Perhaps the common practice of using chest radiographs as follow up is more due to its wide availability, low cost, and minimal X-ray exposure.
The majority of CT scans were performed for "old" patients. Most of these patients received one assessment (85%), but for two-thirds of patients this assessment constituted more then 1 CT procedure. The reason for ordering CT scans (Figure 8
) differed slightly from the reason for ordering all of the imaging procedures when considered together (Figure 6). CT scans were used more to evaluate the response to treatment, rather than to evaluate new problems or for routine follow up. Perhaps this reflected a high degree of success in the initial primary management of lymphomas. The data showed that although follow-up accounted for 21% of all imaging assessments, only 25 CT assessments were done for routine follow-up within the 3-month period (i.e. 8% of all CT assessments). Of these, 92% were ordered by medical oncologists and 8% by radiation oncologists. The reason for this discrepancy could be due to differences in the patient factors seen by the two specialties (a higher patient volume, with a higher risk of relapse in more advanced stage patients seen by medical oncologists) or, alternatively, patients seen by radiation oncology may be more likely to have follow up imaging performed elsewhere.
Many studies have suggested surveillance follow-up routines based on effectiveness, both in terms of the ability to detect relapse and cost [2, 5, 7–9, 11–13]. Not all of the recommended standards are in agreement, ranging from basic history, physical examination and serum lactic dehydrogenase (LDH) tests for follow up [8], which is similar to the practice at our hospital, to a combination of physical examination, blood work, chest radiograph and additional imaging tests such as CT and gallium scans left to the discretion of the investigator [11]. The United States National Comprehensive Cancer Network 2004 practice guidelines for Hodgkin's disease, which are based on consensus rather than published data, outline an even more intensive follow up routine that entails chest imaging (CT scan or radiograph), to be performed every 3–6 months during the first 3 years post-treatment and annually from the 4th year after treatment [19]. Abdominopelvic imaging was recommended every 6–12 months in the first 3 years post treatment, and annually in years 4 and 5. For patients treated with radiation therapy to the chest, mammographic screening was suggested 8–10 years post-therapy. The follow up guidelines for NHL were not detailed, except for follicular lymphoma where follow up imaging was regarded as necessary but ordered as clinically indicated, about every 6 months [20]. An international workshop that established standardized response criteria in NHL stated that "imaging studies may be added for relevant clinical indications, but specific tests cannot be currently recommended", yet acknowledges that the issue is still controversial and that good clinical judgement is the most important component of patient follow up [2]. In one study of Hodgkin's disease, among patients with recurrence of disease, imaging-detected cases did not have a better overall clinical outcome with salvage therapy compared with patients whose recurrence were detected by symptoms [12].
A limitation of this study is the retrospective nature of the review, as it is possible that a clinician had ordered an imaging procedure with a legitimate indication, but did not document this in the medical record either before or after the imaging procedure was performed. Such a situation will be misclassified under the category of "routine follow up with no specific clinical indication". Given this limitation, the 8% rate of utilization of CT scans for this reason is probably acceptable within a practice environment where there had been significant variation in the follow up recommendations as cited above. In addition, other institutions with different referral pattern and case-mix will invariably find a very different spectrum for the reasons behind imaging utilization. However, it is the feasibility of the methodology and the potential usefulness of the auditing procedure in assessing and assigning resource utilization in this study that should be emphasised. Increasingly, stakeholders of the healthcare delivery system such as government, health authorities and hospital boards demand accurate utilization data to assign resources, and the type of information requested is often along the same vein as that provided in this study.
In conclusion, in the lymphoma patients seen at a tertiary oncology hospital, imaging assessments requested for staging are under-represented. A substantial proportion of patients having had imaging tests completed elsewhere prior to referral explained this. Imaging requested for routine follow up of asymptomatic lymphoma patients is infrequent, apart from chest radiographs. This study reflects the utilization patterns of imaging within a disease group and would assist in planning the assignment of imaging resources based on case-mix. It also reassured the physicians and the institution that the majority of CT scans were ordered for valid indications. It is hoped that the study also raised the awareness of clinicians in the importance of continually adhering to proper indications for ordering imaging tests.
Received for publication April 26, 2005.
Revision received June 1, 2005.
Accepted for publication June 22, 2005.
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BJR review of the year - 2006
Br. J. Radiol.,
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80(951):
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Abstract
Introduction
