Journal of the American College of Radiology
Volume 9, Issue 1 , Pages 33-41, January 2012

Growth in the Use of PET for Six Cancer Types After Coverage by Medicare: Additive or Replacement?

  • Bruce E. Hillner, MD

      Affiliations

    • Department of Internal Medicine and the Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
    • Corresponding Author InformationCorresponding author and reprints: Bruce E. Hillner, Virginia Commonwealth University, Department of Internal Medicine and the Massey Cancer Center, Sanger Hall, 1101 East Marshall Street, Richmond, VA 23298
    • ,
  • Anna N. Tosteson, ScD

      Affiliations

    • The Dartmouth Institute for Health Policy and Clinical Practice, Dartmouth Medical School, Hanover, New Hampshire
    • ,
  • Yunjie Song, PhD

      Affiliations

    • The Dartmouth Institute for Health Policy and Clinical Practice, Dartmouth Medical School, Hanover, New Hampshire
    • ,
  • Tor D. Tosteson, ScD

      Affiliations

    • The Dartmouth Institute for Health Policy and Clinical Practice, Dartmouth Medical School, Hanover, New Hampshire
    • ,
  • Tracy Onega, PhD

      Affiliations

    • The Dartmouth Institute for Health Policy and Clinical Practice, Dartmouth Medical School, Hanover, New Hampshire
    • ,
  • David C. Goodman, MD

      Affiliations

    • Department of Internal Medicine and the Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
    • ,
  • Barry A. Siegel, MD

      Affiliations

    • Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, and Siteman Cancer Center, Washington University School of Medicine, St Louis, Missouri

Article Outline

Background

In July 2001, PET became a covered service for Medicare beneficiaries when used for the diagnosis, staging, and restaging of non–small-cell lung, esophageal, colorectal, and head and neck cancers as well as lymphoma and melanoma. Whether physicians use PET as a replacement for or in addition to CT, MRI, or bone scintigraphy (BS) is uncertain.

Methods

A 20% sample of Medicare fee-for-service beneficiaries aged > 64 years from 2004 through 2008 was used. Annually for each cancer type, a cohort of patients was created defined as having at least one admission with a primary cancer diagnosis or two nonhospital claims with a cancer diagnosis ≥7 days apart per calendar year. Each year, imaging claims and claim-days were counted by modality and cancer type. The sequence of PET use was examined as before, after, or instead of other imaging.

Results

About 125,000 beneficiaries (2.5% of the cohort) met the cancer definition each year. In 2008, the combined annual imaging days per person-year were 2.3 for CT, 0.49 for MRI, 0.70 for PET, and 0.13 for BS. The annual rates of imaging from 2004 to 2008 increased by 0.5% for CT, 3.2% for MRI, and 18.0% for PET (range, 14.6%-19.9% by cancer type) and decreased by 12.7% for BS. The growth in PET use was not associated with meaningful changes in body CT. In 2007 and 2008, body CT preceded PET within 30 days in about half of patients, whereas PET preceded CT in only 22%.

Conclusions

Several years after its introduction, PET continued to grow rapidly, with evidence that it is replacing BS. Growth of PET occurred without evidence of a decline in body CT. About half of PET use occurred shortly after body CT, suggesting an additive or final arbiter role.

Key Words:  PET , CT , MRI , bone scintigraphy , time trends , lung neoplasms , colorectal neoplasms , melanoma , lymphomas , head and neck neoplasms , esophageal neoplasms , elderly , practice patterns , Medicare

 

Back to Article Outline

Introduction 

Medical imaging serves an integral role at most decision points in cancer care, from diagnosis and initial staging to the termination of therapy for metastatic disease. Advanced imaging use evolved in a disorderly manner after the introduction of CT and, subsequently, MRI. In the absence of randomized trials, appropriateness criteria based on expert opinion using clinical vignettes have been the predominant source of practice guidelines [1, 2, 3].

Over the past decade, 4 trends arose related to cancer imaging. First, the costs of chemotherapies and targeted agents increased rapidly [4]. If cancer imaging could guide the effective use of these therapies, then increased imaging would be more easily defended. Second, the overall costs of medical imaging (not just for cancer) doubled between 2000 and 2006 [5, 6]. Third, CT and MRI scan volumes rose dramatically—by 9.5% per year for CT and 13.1% for MRI between 1998 and 2005—and shifted from predominantly hospital-based sites to freestanding outpatient sites [5, 7, 8]. Fourth, PET using 18F-fluorodeoxyglucose and integrated PET/CT (together referred to hereinafter as PET), a new technology based on a paradigm of characterizing metabolic processes rather than anatomy, was introduced for use in selected cancers. In July 2001 [9], CMS approved reimbursement for PET imaging for evaluating beneficiaries across the natural history—diagnosis, initial staging, and restaging—for 6 cancer types (non–small-cell lung, esophageal, colorectal, and head and neck cancers as well as lymphoma and melanoma).

It remains uncertain whether the growth in PET after the 2001 CMS coverage decision was associated with declines in other imaging. In this study, we assessed for 2004 through 2008 the temporal trends in PET use compared with the concurrent use of CT, MRI, and bone scintigraphy (BS) for these common cancer types. In addition, we assessed the temporal clustering and sequencing of PET use as “new” relative to “established” technologies (CT, MRI, and BS) to characterize its role as an additive or a replacement tool.

Back to Article Outline

Methods 

Design Overview 

To characterize changes in cancer imaging after the 2001 CMS coverage decision for PET, we evaluated Medicare fee-for-service (FFS) claims for cancer beneficiaries identified annually over the period from 2004 to 2008. We used these data to examine the rates and sequencing of advanced cancer imaging. The institutional review board at Dartmouth Medical School approved this study.

Settings and Participants 

For each of these 5 years, we assessed a 20% sample of FFS beneficiaries aged ≥ 65 years as of January 1, enrolled in both Medicare Part A and Part B, and not enrolled for any part of the year in a Medicare managed care program. The advantages of the 20% sample, compared with the more commonly used 5% sample, are the larger counts of relatively uncommon events (eg, cancers of the head and neck and esophagus and melanoma). For each year, we determined whether a beneficiary had a cancer type to be included in the analysis cohort for that year. We used the International Classification of Diseases, ninth rev (ICD-9), to categorize cancer types as follows: head and neck (codes 140-149, 160, and 161), esophagus (code 150), colorectal (codes 153 and 154), non–small-cell lung cancer (code 162), malignant melanoma (code 172), and lymphoma (codes 200-202). The inclusion of a patient in the annual cancer case cohort (denominator) required either (1) a hospital admission for which the principal discharge diagnosis was one of the ICD-9 codes above or (2) two nonhospital claims (primarily physician Part B for office-based visits, procedures, or imaging) occurring ≥7 days apart but in the 12 months of that year, with one of the primary cancer diagnosis ICD-9 codes listed above on both claims. The requirement for at least two claims involving physician contact ≥7 days apart is commonly used in other analyses of administrative data to reduce the likelihood of erroneously including a claim submitted, albeit incorrectly, with a “rule-out” diagnosis [10]. The date of admission or the first of two outpatient claims defined each subject's date of entry to the cohort in any given year. We explicitly did not include claims for hospice or home health care because our intent was to evaluate beneficiaries undergoing active cancer management.

These criteria were applied for defining the cohort in each of the years; that is, the inclusion of any individual patient in the cohort for any year was independent of that individual's inclusion in a prior or subsequent year's cohort. Our inclusion criteria were intended to identify a mixture of beneficiaries with newly diagnosed cancer, those having ongoing care or surveillance after treatment, and those with recurrent cancer.

Definitions of Imaging Type 

Table 1 [11] gives the Healthcare Common Procedure Coding System and Current Procedural Terminology® codes used to define PET, CT, MRI, and BS. More than 99% of PET and BS claims were for torso or whole-body imaging (skull base to thigh for PET). For any year, PET and PET/CT claims were combined. For CT and, to a lesser extent for MRI, multiple claims on the same date for separate body areas were common (eg, chest, abdominal, and pelvic CT) and counted as 1 imaging day. We counted both the CT and MRI claims per year as well as imaging days with CT, MRI, or the combination. Once a beneficiary met our inclusion criteria for a given year, all CT and MRI claims during the remainder of that year were included.

Table 1. Classification of imaging types and body area
Imaging Type and Body AreaHCPCS and CPT® [11] Codes
PET and PET/CT⁎G0210-G0234, G0252-G0254, G0330-G0336, 78608, 78810, 78811-78813(specifically PET), 78814-78816(specifically PET/CT)
CT
Head70450, 70460, 70470
Orbit, sella, posterior fossa, and neck70480-70492
Chest71250, 71260, 71270
Abdomen74150, 74160, 74170
Pelvis72192, 72193, 72194
Other72125-72133, 73200-73205, 73700-73705, 76497
MRI
Brain70551-70553
Spine72141-72158
Other70540-70543, 76498,74181-74183, 73218-73220, 73221-73223, 73718-73719, 73721-73723, 76400, 76093-76094, 71550-71552, 75552-75556, 72195-72197, 76498
BS78300, 78305, 78306, 78315, 78320

We excluded the procedure codes for imaging done concurrently with angiography, for therapy guidance, or after image processing/rendering. We counted only global and professional component claims to avoid double counting examinations with separate technical and professional component claims.

BS = bone scintigraphy; CPT® = Current Procedural Terminology®; HCPCS = Healthcare Common Procedure Coding System.

⁎ In July 2005, coding for PET changed with the introduction of specific CPT® codes based on type of PET imaging that replaced the HCPCS G codes.

Statistical Analysis 

The prevalence of cancer beneficiaries for each year was calculated as the number of patients in the cancer cohort for that year divided by the number of total beneficiaries in the Medicare FFS sample (tabulated from the Medicare Denominator File); this result was reported as the number per 1,000 beneficiaries. Cancer person-years, by individual cancer type or overall, were calculated as the time from first cancer claim to the sooner of the last claim day of the year or the date of death. The ratio of cancer person-years per cancer beneficiary varied by cancer type and paralleled expected survival rates: lowest for lung and esophageal cancers and highest for lymphoma.

The annual change from 2004 to 2008 in the rates of imaging by modality and cancer type was calculated on the basis of the ratio of 2008 rates to 2004 rates, assuming constant annual compounding.

Clustering and sequencing of other advanced imaging studies before and after PET and brain MRI were done for 2007 and 2008. For these years, only PET/CT was evaluated and constituted >90% of all PET imaging. If oncologists were predominantly using PET as an “additive” imaging test to body CT (eg, to confirm inconclusive CT findings or when the potentially greater sensitivity of PET/CT for detecting distant disease was necessary for treatment planning), then the use of PET/CT would be expected to occur after body CT and within a short time interval. Targeted diagnostic CT (eg, with contrast enhancement or multiphase) after PET/CT should occur occasionally to better characterize lesions seen on PET/CT. The same reasoning applies to brain MRI as additional imaging after head CT.

Although the full year was used for overall counts, for the clustering analysis, only the first PET/CT or brain MRI study occurring between February 1 and November 30 per year was flagged. For PET/CT, the number of body CT studies (chest, abdominal, and pelvic) in the preceding 14 or 30 days or the succeeding 14 or 30 days was counted as an indicator of the frequency and timing of CT in relation to PET. To test whether PET occurred primarily before or after other imaging, for those individuals with a first PET instance paired with another imaging test either before or after, we used a one-sample test for proportions with a null hypothesis of equality (0.5) for the before proportion.

In a similar manner, the use of brain MRI within 14 or 30 days after head CT was counted. We anticipated little clustering of PET/CT and brain MRI, with the exception of one efficient sequence wherein initial MRI suggests cerebral metastases and subsequent body PET/CT is used to identify a primary cancer site.

Back to Article Outline

Results 

The numbers of beneficiaries, cancer cases, and cancer person-years are shown in Table 2. From 2004 to 2008, the number of beneficiaries in the 20% FFS sample declined as more beneficiaries enrolled in Medicare Advantage plans. However, the demographics of the samples with respect to age (mean, 75.5 years), gender (58.5% women), and ethnicity (88.0% white, 7.5% black, and 4.5% other) all changed by ≤0.1% from 1 year to another.

Table 2. Study population, cancer cases, and person-years per 1,000 Medicare beneficiaries
200420052006200720082004-2008200420052006200720082004-2008
nnnnnChangePerson-YearsPerson-YearsPerson-YearsPerson-YearsPerson-YearsChange
20% fee-for-service sample (millions)⁎5.415.375.215.105.02
6-cancer total† beneficiaries in year (thousands)126.7127.1125.8124.9123.7 80.380.881.081.080.9
Cancer beneficiaries per 1,000 overall Medicare beneficiaries (% of 6-cancer total)
Combined total23.4(100%)23.6(100%)24.1(100%)24.5(100%)24.6(100%)5.1%14.8(100%)15.0(100%)15.5(100%)15.8(100%)16.1(100%)8.6%
Lung7.32(31.3%)7.42(31.4%)7.58(31.4%)7.76(31.6%)7.86(31.9%)7.3%3.98(26.8%)4.08(27.2%)4.25(27.4%)4.43(28.0%)4.54(28.2%)14.1%
Colon7.40(31.6%)7.22(30.6%)7.20(29.9%)7.13(29.1%)6.98(28.3%)−5.6%4.88(32.9%)4.78(31.9%)4.81(29.1%)4.77(30.2%)4.75(29.4%)−2.8%
Lymphoma4.60(19.6%)4.78(20.2%)5.04(20.9%)5.17(21.1%)5.24(21.3%)13.9%3.34(22.5%)3.46(23.1%)3.69(23.8%)3.81(24.1%)3.87(24.0%)16.0%
Head and neck1.86(7.9%)1.89(8.0%)1.89(7.8%)1.91(7.8%)1.95(7.9%)4.7%1.26(8.5%)1.28(8.5%)1.29(8.3%)1.30(8.2%)1.34(8.3%)6.5%
Malignant melanoma1.62(6.9%)1.69(7.2%)1.74(7.2%)1.83(7.5%)1.92(7.8%)18.2%1.03(6.9%)1.06(7.1%)1.11(7.2%)1.17(7.4%)1.22(7.6%)18.8%
Esophagus0.62(2.7%)0.64(2.7%)0.67(2.8%)0.66(0.27%)0.68(2.8%)8.9%0.32(2.3%)0.36(2.4%)0.38(2.4%)0.38(2.4%)0.39(2.4%)11.3%

Age, gender, and ethnicity all changed by <0.1 (or 0.1%) per year (see text).

⁎ Twenty percent fee-for-service Medicare sample.

† A beneficiary with cancer of a specific type per year was defined as having either (1) any admission with a primary diagnosis of one of the cancer types listed or (2) at least two nonhospital claims ≥7 days apart, each with a primary diagnosis of one of the cancers listed within the 12 months of that year. For each cancer type, person-years per cancer type were determined by the time from the first to the last claim in any year that a beneficiary met the above criteria for a cancer case.

Overall, the number of cases meeting our case definition per 1,000 beneficiaries increased for 5 of the 6 cancer types. The number of cancer cases per 1,000 beneficiaries increased by 5.1% from 2004 to 2008. Increases in lymphoma (13.9%) and melanoma (18.2%) more than offset the decline in colorectal cancers (−5.6%).

The increases from 2004 to 2008 in person-years exceeded those for cancer cases for all 6 cancers. This is consistent with either improved survivorship or more claims (visits or testing). The combined total person-years for the 6 cancer types increased by 8.6%. In 2008, beneficiaries with lymphoma were slightly fewer than those with lung or colorectal cancer (3.87 vs 4.54 and 4.75 per 1,000, respectively).

Imaging Method and Cancer Type 

Comparisons of imaging frequency over 5 years by cancer type provide some insight into differences in site and frequency of metastases as well as how much oncologists are adjusting their imaging between solid tumor types. Figure 1 shows the time trends of CT, MRI, PET, and BS per person-year by cancer type. In this figure, imaging days are used. Given the large sample sizes, 95% confidence intervals were narrow and are not shown in the graphical presentation for clarity.

The use of CT was consistent from year to year within a cancer type but substantially differed among cancer types. Beneficiaries with esophageal and lung cancer had about 3-fold more CT days per person-year than those with melanoma. Year-to-year changes in CT imaging by cancer were minimal, with the exception of lymphoma, for which imaging days per person-year declined by 0.25(3% per year).

MRI was used in lung cancer beneficiaries 2-fold to 3-fold more often than in any of the other cancer types. This likely is due to greater frequency of brain metastases in lung cancer as part of its natural history. Each lung cancer beneficiary had about 1 MRI a day per person-year. The absolute increase in MRI for any of the cancer types was quite small (<0.1 days per year).

The use of PET for all cancer types approximately doubled, from 0.38 to 0.70 imaging days per cancer person-year, an annualized increase of 18.0% per year (ranging from 14.6% per year for esophageal cancer to 19.9% per year for head and neck cancers). As shown in Figure 1C, the absolute use per person-year continued to vary by cancer type. For example, by 2008, PET imaging days were 1.23 per person-year in patients with esophageal cancer compared with 0.44 imaging days in patients with colorectal cancer.

Bone scintigraphy declined markedly for all cancer types and at similar rates. Overall, for the 6 cancers combined, BS use declined 12.7% per year, or 38.0% over the 5 years. The use of BS declined by almost half for lung cancer.

Trends by Imaging Type and Body Site 

At the cohort level, Figure 1 shows the aggregated CT imaging days for all body sites. Figure 2 breaks out the rates per person-year for chest, abdomen, and pelvis. The figure shows that for each of these body sites, CT imaging increased by 3% to 4% per year from 2004 to 2007 and then showed a consistent decline in 2008 of about 6%.

Figure 3 shows the annual rates of brain MRI, head CT, and facial, orbital, and neck CT for 2004 to 2008; both CT and MRI of the head increased, with brain MRI increasing at a slightly faster rate. As observed for body CT, brain imaging declined slightly in 2008.

Time Clustering and Sequencing 

To address the additive vs replacement questions, we switched our analyses to the individual patient level. Figure 4 shows the clustering and sequence pairing of imaging for 2007 and 2008. For these comparisons, only PET/CT (not PET only) were evaluated. For all cancer types, body CT scans preceded PET/CT within 30 days in 47.4% of patients, ranging from 31.4% for melanoma to 58.1% for esophageal cancer. The converse sequence (undergoing body CT within 30 days after PET/CT) occurred in 22.8% of patients and varied minimally across the 6 cancers types. The differences in sequencing for each individual and combined cancer types were all highly statistically significant (P < .001).

Clustering of brain imaging was much less frequent, primarily occurring within 14 days, and predominantly was brain MRI after head CT. Head CT preceded brain MRI within 14 days in 15.2% of all patients (range, 11.0%-16.4% by cancer type; data not shown). A second use of brain imaging was most common in beneficiaries with lung cancer and least common in head and neck cancer.

Back to Article Outline

Discussion 

Over the past 2 decades, rapid growth in imaging volume and a shift to more expensive tests has been observed in Medicare beneficiaries and younger, privately insured patients [5, 6, 7, 8, 12, 13, 14]. This concern received national attention in a 2005 Medicare Payment Advisory Commission report [15]. Factors influencing the growth and likely overutilization of imaging [16] include wider availability, patient demand, self-referral among nonradiologists, competition among specialists, defensive medicine, and nondefinitive interpretations by radiologists. Although greater use of imaging may have value in patient management, there are also possible disadvantages, including financial cost and population radiation exposure. Technological advances in imaging can lead to overestimation of disease burden and of the effectiveness of interventions [17]. This phenomenon is well described for new cancer staging tests, which can cause a spurious stage migration that seemingly improves outcomes for all stages of disease (Will Rogers phenomenon) [18, 19]. Approaches to slow the growth of imaging include radiology benefit management programs requiring prior authorization, computerized physician order entry with decision support, restrictions on self-referrals, and reductions in Medicare technical component payments [5, 16, 20, 21, 22].

In our study, we were specifically interested in the trends of cancer imaging and the diffusion of PET into practice because this technology represents a new paradigm: functional vs structural imaging [23]. Few other reports have specifically focused on medical imaging in cancer patients. Dinan et al [24] recently reported an evaluation of a 5% sample of Medicare beneficiaries from 1999 to 2008 for breast, colorectal, lung, and prostate cancers, as well as leukemia and lymphoma, and tracked 2 years of different types of imaging. Direct comparisons between our findings and those of Dinan et al are limited, as their cohorts began before the July 2001 Medicare coverage expansion for use of PET in diagnosis, staging, and restaging of non–small-cell lung cancer, colorectal cancer, and lymphoma and before the 2002 coverage for breast cancer; these cohorts also included cancers for which the use of PET was not covered (leukemia and prostate cancer) [25]. Nevertheless, we each found that CT and MRI use differed widely by cancer type and minimally differed year to year within a cancer type and that imaging use was greatest in lung cancer.

We intentionally focused on specific cancers with PET coverage by Medicare, and our cohorts began several years after CMS approval to avoid the distortions of comparisons starting from zero use. We evaluated imaging utilization across the continuum of disease (diagnosis or initial staging through suspected recurrences), by body areas (chest, abdomen, and pelvis or brain, head, and neck) of CT and MRI [5, 20]. In contrast to most studies of imaging trends, our unit of analysis was the cancer beneficiary (expressed in cancer person-years), not the overall universe of Medicare beneficiaries. Our use of person-years (instead of persons) as our denominator is an acknowledgment that we were not observing our cohort over a full year and redefined it anew each year; this reduces the estimated rates but did not otherwise affect the analyses.

Our primary finding is that PET use, even 7 years after its Medicare approval, continued to increase at substantial, stable rates for all cancer types. This growth in PET per beneficiary occurred without evidence of a decline in body CT imaging, with the exception of a slight decline among patients with lymphoma. Our analysis of individual-level clustering and sequencing suggests that about half of PET/CT is as an additional test to CT, and about half is temporally unrelated to CT. This additive use of PET likely reflects a mix of clinical intents: resolving inconclusive CT findings (ie, serving as the final arbiter) before therapy is initiated, changed, or stopped and addressing clinical questions not answered by preceding CT, including being a more sensitive detector of metastatic disease. The frequency of PET/CT preceding CT was higher than anticipated but likely reflected the finding on PET/CT of abnormal 18F-fluorodeoxyglucose uptake in body sites not clinically suspected, thus prompting targeted use of CT in a similar arbiter role (eg, contrast-enhanced CT to confirm hepatic metastases suggested by the results of PET/CT in which the CT component was performed without contrast enhancement).

In the initial staging of non–small-cell lung cancer, evidence from randomized trials performed in multiple countries showed that PET is superior to conventional staging and plays a final arbiter role in guiding management; these trials addressed both the use of PET as an addition to conventional staging methods (in older studies) [26, 27, 28, 29] and PET/CT in lieu of conventional staging [30].

However, it is more difficult to infer how much PET is used as a replacement tool because the rates of body CT did not change meaningfully during these years. MRI use in lieu of CT for evaluating potential brain and spinal metastases shows the same trend: modest growth in MRI without declines in CT. However, the sequencing assessment suggests that MRI and CT may be used for different situations because only about 15% of brain MRI examinations were preceded by head CT, a pattern shift seen in the early management of stroke [31, 32].

The marked decline across all cancer types in conventional whole-body BS use is consistent with other international series [33, 34, 35, 36, 37]. Although prostate and breast cancers are the most common cancer-type indication for BS, the observed decline in BS for the 6 different cancers in our cohorts suggests that clinicians are increasingly using a mix of CT, MRI, and PET as alternatives for detection of osseous metastatic disease.

From a disease management and comparative effectiveness perspective, PET imaging of cancer reprises a pattern seen in cardiac and neurologic imaging: the new “better” technique is initially used in addition to older tests or for confirmation with relatively little substitution [14]. The value of the new imaging methods depends on the subsequent management consequences, primarily reflecting a complex combination of treatment decisions: yes or no; continue, switch, or stop; or transition to palliative care [14]. Although there seems to be a distinct slowing of discretionary noninvasive imaging since 2005 in the Medicare FFS population [38], there is little evidence for switching. The slight declines in body CT and MRI in 2008 may reflect the overall impact of the 2005 Deficit Reduction Act, which sharply reduced private office technical component payments. It is difficult to assess retrospectively if a failure to switch (from body CT to PET/CT) reflects a quality of care issue or a potential role of financial incentives because of oncologist ownership of onsite CT scanners [38, 39].

Current guidelines, the rarity of randomized trials, and a general lack of rigor in assessing imaging technologies [40, 41] are parts of the problem. For the 6 cancer types evaluated, current National Comprehensive Cancer Network guidelines infrequently make definitive statements that PET is preferred or how it should be sequenced relative to CT imaging. In the initial staging of non–small-cell lung and esophageal cancer, guidelines clearly state that PET should follow CT if CT shows no evidence of metastases [1]. However, they do not state that PET should replace chest CT. In other common situations in which PET seems to be superior, such as serial elevated carcinoembryonic antigen levels after surgery in patients with colorectal cancer [23, 42], monitoring high-risk patients with melanoma [43], or after initial treatment with chemotherapy or radiation therapy in patients with head and neck cancers [23, 44, 45], PET/CT is considered optional rather than preferred on the basis of expert consensus [1].

Our study's primary limitation was its unconventional approach to defining the cancer cohort. Inherently, our stringent definition does not allow a continuity profile over years and could not assess where each patient was in the course of the disease (initial staging vs surveillance vs suspected recurrence). For example, beneficiaries in remission having only 1 day of evaluation, including imaging, per year would be missed. Studies using linked registry data, usually Surveillance, Epidemiology, and End Results, have a clear cancer identification point and can easily define an initial therapy period but, after the first year, have the same limitations in inferring clinical intent of imaging. Also, our analysis did not attempt to distinguish the indications for CT and MRI, thereby likely overestimating the cancer-specific rates.

This work or other claims-based analyses of care patterns cannot determine clinical intent, particularly with regard to the evolving role of PET in lieu of CT for treatment monitoring (especially in patients with lymphoma) [46] and in changing or stopping systemic therapies when cancer progression is suspected. In future work, we will measure the association of PET with the prevalence of active treatment in the last few months of life.

Back to Article Outline

Conclusions 

After Medicare coverage of PET, cancer providers rapidly incorporated the use of PET into their management of 6 common cancers. This change in practice was to use the new technique, PET, after first using the current imaging standard, body CT, in about half of cases. Whether PET is associated with superior patient outcomes and affects overall costs will require either studies that measure changes in major decision points along a cancer's natural history or studies that directly measure outcomes.

Back to Article Outline

References 

  1. National Comprehensive Cancer Network . NCCN guidelines . http://www.nccn.org/professionals/physician_gls/f_guidelines.asp Accessed December 27, 2010
  2. American College of Radiology . ACR Appropriateness Criteria® . http://www.acr.org/secondarymainmenucategories/quality_safety/app_criteria.aspx Accessed January 2, 2011
  3. Podoloff DA , Ball DW , Ben-Josef E , et al.  NCCN task force: clinical utility of PET in a variety of tumor types . J Natl Compr Canc Netw . 2009;7(suppl):S1–S26
  4. Meropol NJ , Schrag D , Smith TJ , et al.  American Society of Clinical Oncology guidance statement: the cost of cancer care . J Clin Oncol . 2009;27:3868–3874
  5. Levin DC , Rao VM , Parker L , Frangos AJ . The disproportionate effects of the Deficit Reduction Act of 2005 on radiologists' private office MRI and CT practices compared with those of other physicians . J Am Coll Radiol . 2009;6:620–625
  6. Iglehart JK . The new era of medical imaging—progress and pitfalls . N Engl J Med . 2006;354:2822–2828
  7. Parker L , Levin DC , Frangos A , Rao VM . Geographic variation in the utilization of noninvasive diagnostic imaging: national Medicare data 1998-2007 . AJR Am J Roentgenol . 2010;194:1034–1039
  8. Levin DC , Rao VM , Parker L , Frangos AJ , Sunshine JH . Recent shifts in place of service for noninvasive diagnostic imaging: have hospitals missed an opportunity? . J Am Coll Radiol . 2009;6:96–99
  9. Centers for Medicare and Medicaid Services . PM Rev AB-01-54, expanded coverage of positron emission tomography (PET) scans and related claims processing changes . http://www.cms.gov/transmittals/downloads/R136CIM.pdf December 15, 2000; Accessed January 3, 2011
  10. Welch HG , Sharp SM , Gottlieb DJ , Skinner JS , Wennberg JE . Geographic variation in diagnosis frequency and risk of death among Medicare beneficiaries . JAMA . 2011;305:1113–1118
  11. Beebe M , Dalton J , Espronceda M , Evans D . CPT 2008 professional edition . Chicago, Ill: AMA Press; 2007;
  12. Mitchell JM . Utilization trends for advanced imaging procedures: evidence from individuals with private insurance coverage in California . Med Care . 2008;46:460–466
  13. Mitchell JM . The prevalence of physician self-referral arrangements after Stark II: evidence from advanced diagnostic imaging . Health Aff (Millwood) . 2007;26:w415–w424
  14. Smith-Bindman R , Miglioretti DL , Larson EB . Rising use of diagnostic medical imaging in a large integrated health system . Health Aff (Millwood) . 2008;27:1491–1502
  15. Medicare Payment Advisory Commission . Report to the Congress: Medicare payment policy . http://www.medpac.gov/publications/congressional_reports/Mar05_EntireReport.pdf Accessed December 30, 2010
  16. Hendee WR , Becker GJ , Borgstede JP , et al.  Addressing overutilization in medical imaging . Radiology . 2010;257:240–245
  17. Black WC , Welch HG . Advances in diagnostic imaging and overestimations of disease prevalence and the benefits of therapy . N Engl J Med . 1993;328:1237–1243
  18. Feinstein AR , Sosin DM , Wells CK . The Will Rogers phenomenon . N Engl J Med . 1985;312:1604–1608
  19. Rosselli Del Turco M , Palli D , Cariddi A , Ciatto S , Pacini P , Distante V . Intensive diagnostic follow-up after treatment of primary breast cancer (A randomized trial. National Research Council Project on Breast Cancer Follow-Up) . JAMA . 1994;271:1593–1597
  20. US Government Accountability Office . Medicare: trends in fees, utilization, and expenditures for imaging services before and after implementation of the Deficit Reduction Act of 2005(GAO-08-1102R) . http://www.gao.gov/new.items/d081102r.pdf Accessed January 2, 2011
  21. Rosenthal DI , Weilburg JB , Schultz T , et al.  Radiology order entry with decision support: initial clinical experience . J Am Coll Radiol . 2006;3:799–806
  22. Blackmore CC , Mecklenburg RS , Kaplan GS . Effectiveness of clinical decision support in controlling inappropriate imaging . J Am Coll Radiol . 2011;8:19–25
  23. Juweid ME , Cheson BD . Positron-emission tomography and assessment of cancer therapy . N Engl J Med . 2006;354:496–507
  24. Dinan MA , Curtis LH , Hammill BG , et al.  Changes in the use and costs of diagnostic imaging among Medicare beneficiaries with cancer 1999-2006 . JAMA . 2010;303:1625–1631
  25. Centers for Medicare and Medicaid Services . Pub 100-03 Medicare national coverage determinations (Transmittal 31) . http://www.cms.hhs.gov/Transmittals/downloads/R31NCD.pdf
  26. Fischer B , Lassen U , Mortensen J , et al.  Preoperative staging of lung cancer with combined PET-CT . N Engl J Med . 2009;361:32–39
  27. Herder GJM , Kramer H , Hoekstra OS , et al.  Traditional versus up-front 18F fluorodeoxyglucose-positron emission tomography staging of non-small-cell lung cancer: a Dutch cooperative randomized study . J Clin Oncol . 2006;24:1800–1806
  28. van Tinteren H , Hoekstra OS , Smit EF , et al.  Effectiveness of positron emission tomography in the preoperative assessment of patients with suspected non-small-cell lung cancer: the PLUS multicentre randomised trial . Lancet . 2002;359:1388–1393
  29. Viney RC , Boyer MJ , King MT , et al.  Randomized controlled trial of the role of positron emission tomography in the management of stage I and II non-small-cell lung cancer . J Clin Oncol . 2004;22:2357–2362
  30. Maziak DE , Darling GE , Inculet RI , et al.  Positron emission tomography in staging early lung cancer: a randomized trial . Ann Intern Med . 2009;151:221–228
  31. Chalela JA , Kidwell CS , Nentwich LM , et al.  Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison . Lancet . 2007;369:293–298
  32. van der Worp HB , van Gijn J . Clinical practice (Acute ischemic stroke) . N Engl J Med . 2007;357:572–579
  33. Morris PG , Lynch C , Feeney JN , et al.  Integrated positron emission tomography/computed tomography may render bone scintigraphy unnecessary to investigate suspected metastatic breast cancer . J Clin Oncol . 2010;28:3154–3159
  34. Song JW , Oh Y-M , Shim T-S , Kim WS , Ryu J-S , Choi C-M . Efficacy comparison between 18F-FDG PET/CT and bone scintigraphy in detecting bony metastases of non-small-cell lung cancer . Lung Cancer . 2009;65:333–338
  35. Takenaka D , Ohno Y , Matsumoto K , et al.  Detection of bone metastases in non-small cell lung cancer patients: comparison of whole-body diffusion-weighted imaging (DWI), whole-body MR imaging without and with DWI, whole-body FDG-PET/CT, and bone scintigraphy . J Magn Reson Imaging . 2009;30:298–308
  36. Ozülker T , Kücükoz Uzun A , Ozüulker F , Ozpaçac T . Comparison of 18F-FDG-PET/CT with (99m)Tc-MDP bone scintigraphy for the detection of bone metastases in cancer patients . Nucl Med Commun . 2010;31:597–603
  37. Liu T , Xu J-Y , Xu W , Bai Y-R , Yan W-L , Yang H-L . Fluorine-18 deoxyglucose positron emission tomography, magnetic resonance imaging and bone scintigraphy for the diagnosis of bone metastases in patients with lung cancer: which one is the best? (A meta-analysis) . Clin Oncol . 2011;23:350–358
  38. Levin DC , Rao VM , Parker L , Frangos AJ , Sunshine JH . Bending the curve: the recent marked slowdown in growth of noninvasive diagnostic imaging . AJR Am J Roentgenol . 2011;196:W25–W29
  39. Levin DC , Rao VM . The effect of self-referral on utilization of advanced diagnostic imaging . AJR Am J Roentgenol . 2011;196:848–852
  40. Blackmore CC , Medina LS . Evidence-based radiology and the ACR Appropriateness Criteria® . J Am Coll Radiol . 2006;3:505–509
  41. Fryback DG , Thornbury JR . The efficacy of diagnostic imaging . Med Decis Making . 1991;11:88–94
  42. Metser U , You J , McSweeney S , Freeman M , Hendler A . Assessment of tumor recurrence in patients with colorectal cancer and elevated carcinoembryonic antigen level: FDG PET/CT versus contrast-enhanced 64-MDCT of the chest and abdomen . AJR Am J Roentgenol . 2010;194:766–771
  43. Fuster D , Chiang S , Johnson G , Schuchter LM , Zhuang H , Alavi A . Is 18F-FDG PET more accurate than standard diagnostic procedures in the detection of suspected recurrent melanoma? . J Nucl Med . 2004;45:1323–1327
  44. Lonneux M , Hamoir M , Reychler H , et al.  Positron emission tomography with 18F fluorodeoxyglucose improves staging and patient management in patients with head and neck squamous cell carcinoma: a multicenter prospective study . J Clin Oncol . 2010;28:1190–1195
  45. Scott AM , Gunawardana DH , Bartholomeusz D , Ramshaw JE , Lin P . PET changes management and improves prognostic stratification in patients with head and neck cancer: results of a multicenter prospective study . J Nucl Med . 2008;49:1593–1600
  46. Juweid ME , Stroobants S , Hoekstra OS , et al.  Use of positron emission tomography for response assessment of lymphoma: consensus of the imaging subcommittee of international harmonization project in lymphoma . J Clin Oncol . 2007;25:571–578

 Primary funding source: National Institutes of Health; National Cancer Institute Grand Opportunity Award RC2CA148259.

PII: S1546-1440(11)00338-3

doi:10.1016/j.jacr.2011.06.019

Journal of the American College of Radiology
Volume 9, Issue 1 , Pages 33-41, January 2012

Article Tools

* Image Usage & Resolution