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© 2001 American Society for Clinical Oncology Impact of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography on Patient Management: First Year’s Experience in a Clinical CenterFrom the Hamamatsu/Queen’s Positron Emission Tomography Imaging Center, Queen’s Medical Center, Honolulu, HI. Address reprint requests to Robert V. Tucker, DrPH, Queen’s Medical Center, Cyclotron Laboratory, 1301 Punchbowl St, Honolulu, HI 96813; email: trobertv{at}aol.com
PURPOSE: To measure the impact of whole-body fluorodeoxyglucose (FDG) positron emission tomography (PET) on patient management during its first year of use in a community hospital. MATERIALS AND METHODS: First-year FDG-PET impact was determined from 463 referring physicians’ evaluations of their patients’ PET imaging results using two surveys. Survey 1 was given to all physicians referring patients to PET to discover whether PET changed patient management or had decision-making value in the patient’s clinical algorithm. Survey 2 was given to one surgeon and one pulmonologist after therapy to determine how PET affected the surgical, chemotherapeutic, and/or radiotherapeutic treatment for the 53 cancer patients they referred. RESULTS: The 463 responses to survey 1 described 23 different PET indications. Lung (40%), head and neck (18%), and colorectal cancers (11%) were the three leading causes of referral. PET changed patient management/therapy in 45% of all patients referred and had inferential/decision-making value in another 44%. Overall, PET had some type of positive influence in 412 (89%) of the patients. Survey 2 provided a more detailed assessment of 53 referrals from two specialists. PET positively affected surgery in 31 patients (58%), prompted the addition of chemotherapy or radiation therapy in nine patients (17%), and eliminated chemotherapy or radiation therapy in four cases (8%). Overall, PET affected patient management/therapy in 70% of the cases and had some decision-making value in another 26%, for a combined PET impact on patient management of 96%. CONCLUSION: FDG-PET can be valuable for physicians in clinical practice. Its sensitivity and specificity in metabolic imaging, when combined with complementary anatomic imaging techniques, contribute significantly to the clinical treatment of cancer patients. In addition, the high accuracy of FDG-PET makes it a cost-effective radiologic procedure in the work-up of all suspected and/or recurrent cancer patients. Further research is needed to link this demonstrated impact on patient management to cost-effectiveness.
THE AMERICAN CANCER Society estimates that in United States (US) last year, approximately 552,200 Americans will die of cancer, with more than 1,500 dying each day.1 Cancer is the second leading cause of death in the US, exceeded only by heart disease. In the US, one of four deaths is from cancer. Nearly five million lives have been lost to cancer since 1990. In 2000, approximately 1,220,100 new cancer cases were diagnosed. Positron emission tomography (PET) provides a noninvasive method to study tumor pathophysiologic processes in vivo, with the added advantage that the information obtained can be displayed in a manner similar to conventional imaging,2 ie, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography. Whole-body fluorine-18 fluorodeoxyglucose (FDG) PET has been shown to be an effective tool in diagnosing cancer because of its high sensitivity and specificity in diagnostic staging of new or recurrent carcinomas.3-6 This high rate of sensitivity and specificity is due to the abnormal metabolism of cancer cells and their increased glucose utilization. PET uses a radionuclide, which decays with the emission of positively charged particles (positrons). FDG is a radionuclide-labeled analog of glucose that detects cancer cells by its increased uptake, which is similar to that of glucose. The emitted positrons travel a few millimeters in tissue before combining with negatively charged electrons, converting mass into energy, and releasing two high-energy (511 keV) photons (gamma rays), which are emitted at approximately 180 degrees to each other. The simultaneous detection of these photons by the PET scanner is then used to construct a three-dimensional image of these events.7 The purpose of this study was to measure the influence PET imaging on patient management in a community center rather than the traditional academic or research center, where most work on this subject has been performed. The resulting beneficial influence was revealed by two separate surveys. One broad survey was given to all referring physicians and surgeons, and one detailed assessment was given to two clinicians, a pulmonologist and an oncologic surgeon, after therapy to specifically evaluate PET’s impact on cancer care.
The surveys addressed the effect of PET on the clinical care of patients seen at the Hamamatsu/Queen’s PET Imaging Center (Honolulu, HI) between October 1, 1998, and September 30, 1999. Survey 1 covered 517 patients (18 years of age or older). These patients underwent either whole-body or limited topographic scans of specific physiologic regions as indicated by the attending physician’s clinical diagnoses. Whole-body scanning was used for qualitative evaluation for potential metastatic disease. Regional studies were used for specific organ pathology or physiologic measurements necessary for the patient’s care, ie, viable myocardium. The results of each patient’s PET assessment were then given to each respective referring physician and/or surgeon after they had been evaluated by two experienced nuclear medicine physicians. Survey 1 was sent to each referring physician approximately 1 week after the evaluation, thereby allowing sufficient time for the PET results to have been used in that referring physician’s therapeutic decision for his or her patient. The purpose of survey 1 was to discover whether PET changed patient management (yes or no) and, if there was no change in management, whether PET had decision-making value in the patient’s clinical algorithm (yes or no). The second PET survey was given to two clinicians selected from the respondents to survey 1. These clinicians (one pulmonologist and one oncologic surgeon) were chosen for this appraisal because of their subspecialties and the frequency with which they used the PET procedure for tumors during the study period. These clinicians responded by returning surveys on how PET’s findings either changed patient management in terms of its effect on surgery, chemotherapy, and/or radiation therapy or had decision-making value, ie, by reaffirming the previously decided therapeutic course, for 53 of their patients evaluated by PET. All patients were scanned on a 32-ring Hamamatsu SHR-22000 tomograph (Hamamatsu City, Japan) at The Queen’s Medical Center, Honolulu, HI. This tomograph provides 63 contiguous image slices per frame and a 22.4-cm axial field-of-view. Transaxial spatial resolution is 3.5 mm full width at half maximum (FWHM) at the center of the field of view, and the z-axis resolution is 4.0 mm FWHM. Each ring has 672 bismuth germinate (BGO) crystal elements, for a total of 21,504 elements used for two-dimensional acquisition. All patients fasted for at least 4 to 6 hours before FDG-PET scanning. A dose of 370 to 550 MBq of FDG was administered intravenously as a bolus. After tracer injection, patients were kept well-hydrated; some received a diuretic to minimize image artifacts from urinary stasis in the renal-collecting system and bladder. Patients were then asked to lie comfortably to avoid muscular tracer accumulation for approximately 60 minutes before the emission scan. The computer used for image processing was a Hewlett Packard (Palo Alto, CA) Visualize Workstation, model C160. Proprietary software was developed by Hitachi, Ltd, Tokyo, Japan, and Medasys Digital Systems, Miami, FL. Scans were acquired in two dimensions and reconstructed using filtered back projection. All images for clinical evaluation were without attenuation correction, except for brain and cardiac studies.
Survey 1 A total of 463 (90%) surveys were analyzed out of the 517 returned; 54 surveys were excluded because they were either uninterpretable or had incomplete data. Twenty-three different PET referrals ( Table 1) were made to the Hamamatsu/Queen’s PET Imaging Center during this period. The leading three reasons for referral were lung (40%), head and neck (18%), and colorectal (11%) malignancies. These studies were performed mostly for staging or recurrence of disease.
PET’s value and influence on the referring physician’s patient management are described in Table 2. PET changed patient management in 208 cases (45%) and had some decision-making or inferential value for another 204 patients (44%). Overall, PET had some type of value or influence in 412 cases (89%).
Survey 2 The pulmonologist and oncologic surgeon were given their 53 cases (30 and 23, respectively) pulled from the initial 463 surveys. The purpose here was to provide a more detailed assessment of how PET changed management after initial therapy in their cancer patients. The main indication for PET referral in this analysis was lung cancer (43 cases [81%]). This more detailed assessment (Tables 3 and 4) documented PET’s impact on the patient’s therapy, ie, surgery canceled, permitted, or changed, chemotherapy added or eliminated, and radiation added or eliminated. It also gauged the value if the therapy was not affected by the PET results, ie, reassurance of course decision. Survey 2 showed an even more dramatic impact on patient management. PET affected patient therapy in 37 cases (70%) and had some decision-making value in 14 cases (26%). The combined value or impact PET had for 51 of the referred 53 patients was 96%. These influences affected surgery in 31 cases (58%), with PET causing the cancellation of surgery in 20 cases (33%). It prompted the addition of chemotherapy and/or radiation therapy in nine cases (15%) and eliminated chemotherapy and/or radiation therapy in another four patients (7%). In personal communication with both the pulmonologist and oncologic surgeon, the most significant impact of PET in their clinical practice was to change patient management.
Survey 1 and Survey 2 Two categories were identical in the first and second surveys and allowed a direct comparison ( Table 5): (1) yes, PET changed patient management (45% in survey 1 and 70% in survey 2), and (2) PET had no effect on patient management but had decision-making value, ie, it confirmed staging or diagnosis (44% of the cases in survey 1 and 26% in survey 2). Combining these two beneficial results for each independent group of patients (412 patients [89%] for survey 1 and 51 patients [96%] in survey 2), the study demonstrated that PET had beneficial value for the clinicians making the referral.
FDG-PET imaging has become more widely available for clinical use in the last 5 years; it is moving from academic and research institutions into community hospitals and imaging centers. The main clinical use of PET is to identify and stage multiple tumor types, including lung, breast, head and neck, and colorectal carcinomas.8-11 The majority of these studies show FDG-PET to be superior to conventional imaging, such as CT and MRI, for the diagnosis and staging of malignant tumors. This has been particularly notable in the evaluation of recurrent or metastatic disease, including both local/regional and distant tumor spread. FDG-PET is also used in cardiac assessments for viable myocardium and evaluating seizure disorders but at a lower frequency than identifying and staging tumors. We looked at 463 cases in which 23 different referrals for a FDG-PET scan were evaluated by physicians/surgeons in survey 1. The largest referral site was the lung, with 183 referrals (40%). It was found that PET affected patient management change in 208 patients (45%). These findings are approximately equivalent to those in the study by Fong et al,12 in which PET influenced management in 16 (40%) of 40 patients with colorectal cancer. Lai et al6 demonstrated that PET influenced management in colorectal cancer for 10 (29%) of 34 cases. Survey 2 showed that 33% of surgeries (20 of 53; 16 for lung cancer, two for colon cancer, one for liver cancer, and one for sarcoma) were canceled after PET, as compared with 28% reported by Valk et al13 (five of 18 for lung cancer), 29% reported by Boykin et al14 (four of 14 for colorectal cancer), 13% reported by Fong et al12 (five of 40 for colorectal cancer), and 11% reported by Valk et al (five of 45 for melanoma). In addition to changing patient management, our surveys demonstrated the decision-making value of PET in physicians’ critical therapeutic judgment of the patient’s clinical algorithm. PET’s diagnostic results had decision-making value for 204 patients (44%) in survey 1 and for 14 (26%) of the 53 patients seen by the two specialists in survey 2. Flamen’s et al15 research reflects this decision-making value in two groups of colorectal cancer patients. The first group comprised 60 patients in whom conventionally diagnosed imaging devices detected a locoregional or liver recurrence. In this group, Flamen et al showed that PET had diagnostic value in 12 (20%) of the 60 patients. The second group consisted of 13 patients with inconclusive conventionally diagnosed imaging results with elevated carcinoembryonic antigen (CEA) plasma levels. In these patients, PET had diagnostic value in eight (62%) of the 13 patients. The last important measure to be discussed is PET’s combined impact on both patient management and decision making. This effect was calculated by simply adding those patients in whom PET changed management and those patients in whom PET had diagnostic decision-making value. Survey 1 had a combined positive effect or impact on 412 patients (89%), and in survey 2, the combined value for the 51 patients was 96%. The rate with which FDG-PET results lead to alterations in clinical management clearly depends on the specific therapeutic philosophy used by the evaluating surgeon and/or physician. This therapeutic philosophy depends on the confidence that the surgeon and/or physician has in his or her own ability to make a diagnosis. This ability to make a diagnosis is then dependent on the diagnostic tools available to the clinicians, their trust in the results received, and the weight given to any individual result as compared with the other diagnostic modalities requested for that patient. This study validates the effectiveness of PET’s ability to both change and influence patient management. It is hoped that this PET validation will have an impact on surgeons’ and physicians’ therapeutic philosophies and lead to better quality care for their patients, while providing a cost-effective approach.16 Although this study and its referenced articles all confirm the significant role for whole-body FDG-PET imaging in cancer diagnosis, several limitations need to be discussed. First is patient selection bias based on clinical need. All referenced articles are retrospective medical chart reviews of previously studied PET referrals. This study is also retrospective but used surveys contrasting how PET affected patient management in all physician referrals. However, all retrospective studies are susceptible to patient selection bias. This bias is based on the fact that the majority of the scans were performed because of clinical need. It is possible that most of the patients had locally advanced disease with a higher probability of local lymph node involvement or distant metastases. Therefore, the results may favor a test that is better at detecting distant metastases, ie, the PET. The second limitation is that the patients referred to Hamamatsu/Queen’s PET imaging center can come from different institutions where the standardization/quality of the CT scan may be different. However, these scans would be the actual scans used for clinical judgment without PET. Although, the interpretations of the PET scans were not blinded to the CT results, most of the discordant findings were not evident on the CT scans. Third, we were not able to obtain histologic tissue from every patient or every lesion diagnosed. It should be noted that some of the patients were sent for a PET scan to "test" the procedure before surgery. This may have given us a greater number of histologic evaluations earlier in the year and fewer later during the study period as confidence in the value of FDG-PET scanning increased. The fourth limitation is comparability of findings. Our study categorized PET changing patient management into either yes or no. If yes, did PET permit (contradicting conventional imaging results) surgery, change surgery, or cancel surgery, add or eliminate chemotherapy, and add or eliminate radiation therapy? If there was no change in management, did PET have positive or decision-making value (confirming diagnosis, disease stage, and/or reaffirming previously determined treatment plans) or no value or influence? Comparisons to the referenced articles in this study was difficult because of the different criteria and/or lack of definition for "change" or "no change but had value/influence" in management. Boykin et al,14 Valk et al,13 and Vitola et al17 refer to strictly "surgical changes" in management. Fong et al12 discuss both changes in surgical management and influences on therapy. Lai et al,6 Flamen et al,15 and Jadvar et al18 discuss how PET influenced or changed therapeutic and surgical patient management. The fifth limitation was the site being examined or type of referral. Among the seven studies that were referenced, five were strictly colorectal, one was strictly for melanoma, and one was for lung, colorectal, melanoma, and advanced head and neck tumors. Our study examined 25 referral types. Finally, we did not know how PET influenced the decision making for the other physicians involved (other than the referring clinician) in the treatment of patients in this study, and the number of PET referrals was relatively small, given that this was the first year of PET use in a clinical setting and given physician behavior toward use of an emerging and expensive diagnostic tool when reimbursement by third-party carriers is limited. These differences in management change and value in PET, as reflected in this study, show the increasing awareness of the value of FDG-PET scanning in clinical practice. FDG-PET’s diagnostic value contributes significantly to the clinical treatment of the patients referred for this procedure. It should be considered as a complementary imaging technique that increases the sensitivity and specificity of structural imaging studies. The high accuracy14 of FDG-PET also makes it a cost-effective radiologic procedure19-21 in the work-up of all suspected and recurrent carcinoma patients. Further research is needed to link this demonstrated impact on patient management to cost-effectiveness.16
Supported by Hawaii Medical Services Association and Queen’s Medical Center, Honolulu, HI. We thank Sara Wandell and Susan Block for their technical assistance in preparation of the manuscript.
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Delbeke D, Vitola JV, Sandler MP, et al: Staging recurrent metastatic colorectal carcinoma with PET. J Nucl Med 38: 1196-1201, 1997
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Lai DT, Fulham M, Stephen MS, et al: The role of whole-body positron emission tomography with [18F]fluorodeoxyglucose in identifying operable colorectal cancer metastases to the liver. Arch Surg 131: 703-707, 1996 7. Buonocore E: Comparison of PET with conventional imaging techniques, in Hubner KF, Collmann J, Buonocore E, et al (eds): Clinical Positron Emission Tomography. St Louis MO, Mosby Year Book, 1992, pp 17-27
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Moon DH, Maddahi J, Silverman DH, et al: Accuracy of whole-body fluorine-18-FDG PET for the detection of recurrent or metastatic breast carcinoma. J Nucl Med 39: 431-435, 1998
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Abdel-Nabi H, Koerr RJ, Lamonica DM, et al: Staging of primary colorectal carcinoma with flourine-18 fluorodeoxyglucose whole-body PET: Correlation with histopathologic and CT findings. Radiology 206: 755-760, 1998 10. Gupta NC, Graeber GM, Roger JS, et al: Comparative efficacy of positron emission tomography with FDG-PET and computed tomographic scanning in preoperative staging of non-small cell lung cancer. Ann Surg 229: 286-291, 1999[Medline] 11. Stokkel MPM, ten Broek FW, van Rijk PP: The role of FDG PET in the clinical management of head and neck cancer. Oral Oncol 34: 466-471, 1998[Medline] 12. Fong Y, Saldinger PF, Akhurst T, et al: Utility of 18F-FEG positron emission tomography scanning on selection of patients for resection of hepatic colorectal metastases. Am J Surg 178: 282-287, 1999[Medline] 13. Valk PE, Pounds TR, Tesar RD, et al: Cost-effectiveness of PET imaging in clinical oncology. Nucl Med Biol 23: 737-743, 1996[Medline] 14. Boykin KN, Zibari GB, Lilien DL, et al: The use of FDG-positron emission tomography for the evaluation of colorectal metastases of the liver. Am Surg 65: 1183-1185, 1999[Medline]
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Flamen P, Stroobants S, Van Cutsem E, et al: Additional value of whole-body positron emission tomography with fluorine-18-2-fluoro-2-deoxy-D-glucose in recurrent colorectal cancer. J Clin Oncol 17: 894-901, 1999 16. Robert G, Milne R: A Delphi study to establish national cost-effectiveness research priorities for positron emission tomography. Eur J Radiol 30: 54-60, 1999[Medline] 17. Vitola JV, Delbeke K, Sandler MP, et al: Positron emission tomography to stage suspected metastatic colorectal carcinoma to the liver. Am J Surg 171: 21-26, 1996[Medline] 18. Jadvar H, Johnson DL, Segall GM: The effect of fluorine-18 fluorodeoxyglucose positron emission tomography on the management of cutaneous malignant melanoma. Clin Nucl Med 25: 48-51, 2000[Medline]
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Gambhir SS, Hoh CK, Phelps ME, et al: Decision tree sensitivity analysis for cost-effectiveness of FDG-PET in the staging and management of non-small-cell lung carcinoma. J Nucl Med 37: 1428-1436, 1996
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Hoh CK, Glaspy J, Rosen P, et al: Whole body FDG-PET imaging for staging of the Hodgkin’s disease and lymphoma. J Nucl Med 38: 343-348, 1997
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Scott WJ, Shepherd J, Gambhir SS: Cost-effectiveness of FDG-PET for staging non-small cell lung cancer: A decision analysis. Ann Thorac Surg 66: 1876-1883, 1998 Submitted May 5, 2000; accepted February 6, 2001.
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Copyright © 2001 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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ABSTRACT
INTRODUCTION
