Use Of FDG-PET Research Articles

The role of FDG-PET/CT in gynaecological cancers

There is now a growing body of evidence supporting the use of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in gynaecological malignancies. Although this molecular imaging technique is becoming increasingly available, PET/CT remains an expensive imaging tool. It is essential to be familiar with the circumstances in which FDG-PET/CT can add value and contribute to patient management and indeed to know when it is unlikely to be of benefit. It is also important to understand and recognize the potential pitfalls. FDG-PET/CT has been most widely adopted for staging patients with suspected advanced disease or in suspected recurrence, offering a whole-body imaging approach. However, there is great potential for this technique to act as a predictive biomarker of response to treatment, as well as a prognostic biomarker. In addition, FDG-PET images may now be incorporated into radiotherapy planning in order to refine the delineation of dose according to metabolically active sites of disease. This article reviews the literature that provides the evidence for the use of FDG-PET in gynaecological malignancies, identifies areas of real benefit and future potential, and highlights circumstances where there is limited value.

Significant Prognostic Impact of [18F]Fluorodeoxyglucose-PET Scan Performed During and At the End of Treatment with R-CHOP in High-Tumor Mass Follicular Lymphoma Patients: A GELA-GOELAMS Study

Abstract 877 Introduction:Patients with follicular lymphoma (FL) usually respond well to immuno-chemotherapy as initial treatment and can have long survival times. However, a small proportion of patients are refractory or have early relapses. Early identification of this subgroup of patients could lead to early therapeutic changes and, potentially, to a better prognosis. [18F]Fluorodeoxyglucose-Positron Emission Tomography (FDG-TEP) is widely used for the staging and restaging of aggressive lymphoma patients but little is known about the use of FDG-PET in patients with FL, except that FL is almost uniformly FDG-avid. FDG-PET is not recommended today as a routine procedure in FL patients (Cheson et al. J Clin Oncol 2007). In this first prospective, multicentric study, we evaluated the prognostic value of FDG-PET performed at mid-treatment and at the end of treatment in patients with high-tumor mass FL treated with immuno-chemotherapy in first line. Patients & methods:Patients with previously untreated FL (grades 1–3A) presenting with a high tumor burden as defined by the GELF criteria, were treated with 6 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) plus 2 cycles of rituximab, given every 21 days. Patients did not receive rituximab maintenance. A FDG-PET was performed before treatment, after 4 cycles of R-CHOP (interim FDG-PET: I-PET), and at the end of treatment (final PET: F-PET). FDG-PET scans were first interpreted in each centre, then centrally reviewed by 3 investigators blinded to clinical data. Positivity or negativity was rated according to the Deauville visual semi-quantitative criteria (Meignan M: Leuk Lymphoma 2009), positivity being defined as a fixation at level 4 (FDG uptake superior to that of the liver) or 5 (uptake clearly superior to liver and/or new sites of disease). Results:121 patients were included. The median age was 57 years and the male-to-female ratio was 1.12. Ninety-three percent had Ann Arbor stage III–IV. Ninety-seven percent had a good performance status (ECOG score 0–1). The repartition according to the FLIPI was: 0–1 factors: 15%; 2 factors: 43%; 3–5 factors: 42%. The Kappa coefficient indicated a good degree of concordance between the 3 PET reviewers. The initial FDG-TEP was positive in all except 1 case out of 118 centrally reviewed cases. After central review, I-PET (n=111) was negative in 76% of patients and F-PET (n=106) was negative in 78%. With a median follow-up of 23 months, 2-year-progression-free survival rates for I-PET negative versus positive and for F-PET negative versus positive were I-PET 86% versus 61% (p=0.0046); F-PET 87% versus 51% (p <0.0001), respectively. Two year OS at the end of treatment also significantly differed according to F-PET results: 100% vs 88% (p = 0.0128). Conclusion:In FL patients treated in first line, FDG-PET performed either after 4 cycles of R-CHOP or at the end of immunochemotherapy induction is strongly predictive of outcome. Therapeutic intervention based on TEP results during inductive treatment should be evaluated in the future. Disclosures:Salles:Roche and/or Genetech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genzyme: Membership on an entity's Board of Directors or advisory committees; Calistoga/Gilead: Membership on an entity's Board of Directors or advisory committees.

FDG PET in the management of patients with adrenal masses and adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is a rare tumor with aggressive behavior, high recurrence rate, and rapid evolution. Surgery is the only curative modality, while systemic treatments such as mitotane and chemotherapy associated to locoregional therapeutic tools remain as palliative options. Imaging has an important role in the management of patients with ACC both at diagnosis and during follow-up. First, it is necessary to characterize undetermined adrenal masses, selecting patients for surgery. Then, in case of malignancy, it is mandatory to assess disease extension, to detect early relapse during follow-up, and to evaluate treatment response. Computed tomography scan and magnetic resonance imaging are actually the most used techniques for these intents as they are widely available in clinical practice. (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) is routinely used for other malignancies and, on the basis of published data, is also becoming a promising tool in the management of ACC. Not only is it a diagnostic tool complementary to morphological imaging in the characterization of adrenal masses and in tumoral lesions detection, but it can be also useful to evaluate tumor response to treatment. New tracers and indications for the clinical use of FDG PET in this specific disease still have to be evaluated to assess its role in clinical practice.

Évaluation de la réponse thérapeutique par tomographie par émission de positons (TEP) au 18fluoro-désoxyglucose (FDG) en oncologie-hématologie

18Fluoro-deoxyglucose (FDG) positron emission tomography (PET) is an imaging technique which studies the cellular glucidic metabolism. It is particularly indicated in oncology, especially for cancer diagnosis (with a potential prognosis interest) or detection of recurrence. Because of its functional approach to the tissues, its use has logically evolved into the evaluation of cancer treatments, both for the individual care of patients for clinical trials of new therapies. Also, it tends to displace conventional imaging in this indication, whose main limitation is not to assess the viability of residual masses, potentially necrotic or fibrous after treatment. However, the use of FDG-PET requires a rigorous methodology for both the exams achievement but also for the quality of their interpretation, including the choice of the comparison tool. Based on an increasing literature on the subject, were published and updated interpretation criteria for both lymphoma and solid cancers. For lymphoma, standardized assessment criteria were proposed in 2007 during an International Harmonize Project (IHP). For solid cancers, Positron Emission tomography Response Criteria In Solid Tumors (PERCIST) recommendations version 1.0 were recently proposed by an American workshop in 2009 in order to clarify and standardize practices.

Positron emission tomography in the diagnostic pathway for intracystic infection in adpkd and "cystic" kidneys. a case series

BackgroundIntracystic infection, in Autosomal Dominant Polycystic Kidney Disease (ADPKD) and in kidneys with multiple cysts, is a diagnostic and therapeutic challenge, as conventional imaging techniques may not discriminate among "complicated" cysts (infection, bleeding, neoplasia), and as the clinical picture may be attenuated, in particular in early phases. Positron Emission Tomography with fluorodeoxyglucose (FDG-PET) was recently suggested as a tool to detect infection in ADPKD, in single cases and small series.The aim of the study was to report on the role of FDG-PET in the work-up of 10 cases of suspected cystic infections, affected by ADPKD or with multiple kidney cysts.MethodsObservational study. Review of clinical charts and of the imaging data since the use of FDG-PET for detecting cystic infections (2008-2010).ResultsIn 2008-2010, 6 patients with ADPKD and 4 with multiple kidney cysts were referred for suspected intracystic infections (3 males, 7 females, aged 55-83 years, in all CKD stages); in one case the imaging was done in the work-up of a complicated "uremic" cyst. The clinical picture, the usual inflammatory markers and/or the conventional imaging techniques did not allow conclusive diagnosis at referral or during follow-up (ultrasounds in all, CT in 8/10). Nine patients displayed inflammatory signs (increase in C-reactive protein and other biochemical markers) and constitutional symptoms (fever in 9/10).FDG-PET was positive in 6 cases (5 kidney and 1 liver cyst), was repeated during follow-up in 4 patients and was negative in 4 cases. In the positive cases, FDG-PET guided the therapeutic choices; in particular, the duration of therapy was supported by imaging data in the 4 cases with multiple scans. No relapse was recorded after discontinuation of antibiotic therapy in the treated patients. The negative cases did not develop clinical signs of cystic infection over follow-up.ConclusionIn this case series, the largest prospective one so far published and the only one including different types of renal cysts, FDG-PET is confirmed as a promising diagnostic tool for detecting intracystic infection in ADPKD and in multiple kidney cysts, and a potential guide for tailoring therapy. Further larger and multicenter studies are needed to evaluate the cost-benefit ratio and the limits of this imaging technique in the clinical setting.

Maladie de Kikuchi et lupus : à propos d’une observation, revue de la littérature et intérêt de la tomographie par émission de positons au 18F-Fluorodésoxyglucose (TEP–TDM FDG)

Kikuchi disease is a rare entity characterized by lymphadenopathy and fever. Pathology study of lymph node biopsies provides the diagnosis. The disease course is favorable. The disease can occur isolated, or associated with other pathologies including lupus or mixed connective tissue disease. We report a case of Kikuchi disease in a 35-year-old woman, occurring 12years after the diagnosis of overlap syndrome with antiphospholipid antibodies. The patient was given prednisone 25mg per day and long-term hydroxychloroquine. FDG PET/CT showed FDG-avidity nodular masses. After bolus corticosteroid therapy, outcome was favorable with disappearance of metabolic hyperactivity on the FDG PET/CT. The bolus prednisone treatment could then be discontinued. In the 61cases of Kikuchi disease and lupus associations previously published, Kikuchi disease was diagnosed after lupus in only 13% of the observations. In these cases, use of FDG PET/ CT was not reported. For us, FDG PET/CT was useful for diagnosis, for choosing the biopsy site and for follow-up.

Ruolo emergente nella pratica clinica della PET con 18F-FDG nei pazienti con sarcoidosi

Summary Introduction The purpose of this article is to examine the emerging role of whole-body positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in patients with sarcoidosis. Materials and methods We reviewed the literature on the use of FDG-PET in patients with sarcoidosis to identify how this technique is being applied in clinical practice. Results and discussion Our review shows that: 1) sarcoidosis is commonly associated with increased FDG uptake. Therefore, positive findings should be interpreted with caution when FDG-PET is being used to distinguish benign from malignant abnormalities; 2) FDG-PET seems to be a very useful molecular imaging method for staging sarcoidosis, identification of occult sites of involvement, guiding biopsy procedures, and monitoring patients’ responses to treatment; and 3) in patients with sarcoidosis, the diagnostic accuracy of FDG-PET is superior to that of 67Ga scintigraphy.

Functional imaging of infection: conventional nuclear medicine agents and the expanding role of 18-F-FDG PET

A growing body of literature suggests that 18-fluorine fluorodeoxyglucose positron emission tomography ((18)F-FDG PET), particularly when combined with CT, is a useful tool for the detection of infectious and inflammatory disease processes. This article will briefly review the data to date on the use of FDG PET in diagnosing musculoskeletal infections and fever of unknown origin, comparing it to conventional scintigraphic techniques in both adults and, when available, in children.

The use of FDG-PET to guide consolidative radiotherapy in patients with advanced-stage Hodgkin lymphoma with residual abnormalities on CT scan following ABVD chemotherapy.

8034 Background: Consolidative radiotherapy (RT) is frequently administered following chemotherapy (CHT) for advanced stage Hodgkin lymphoma (HL) patients who have bulky disease at diagnosis and/or residual abnormalities on post-CHT CT imaging. The GHSG HD15 trial has recently shown that RT can be omitted in cases that have residual disease on CT imaging following BEACOPP-based CHT but are FDG-PET-negative (PET-neg). However, it is unknown whether this also applies to patients treated with ABVD CHT and to those with initial bulky disease. Further, the effectiveness of RT for cases that are PET positive (PET-pos) following ABVD CHT remains unclear. Methods: Since July 2005, adult (> 16 y) patients in British Columbia (BC) with advanced stage HL (stage III /IV and/or the presence B symptoms and/or bulky disease [> 10cm]) have been recommended to undergo FDG-PET imaging if residual abnormalities > 2 cm are seen on the post CHT CT scan. If the PET scan was negative, patients were observed, regardless of initial disease bulk. If the PET scan was positive RT was administered, if feasible. Results: In total, 163 patients responding patients have had a PET scan following curative intent ABVD or equivalent CHT: PET-neg 80% (n=130); PET-pos 19% (n=31); PET-indeterminate 1% (n=2). Patient characteristics include: M:F 1:1.04; median age, 31 y (17-76 y); stage II, 52%; bulky disease, 50%; B symptoms, 68%; IPFP Prognostic score > 3, 15%. With a median follow-up of 34 months, patients with a PET-neg scan post CHT have a far superior 3-year TTP compared to those with a PET-pos scan (89% vs 55%, p= .00001). In the PET-neg patients, there was no difference in the 3-year TTP in those with bulky vs non-bulky disease at diagnosis (86% vs 91%, p=.71). In the PET-pos group, 25 (81%) received the planned RT and of these, 10 (40%) have relapsed. Conclusions: Advanced stage HL patients with a negative PET scan following ABVD CHT are at low risk of relapse and do not routinely require additional consolidative RT thus avoiding potential long-term side effects. Although some patients with a positive PET-scan remain disease free after consolidative RT, a high proportion ultimately relapse.

FDG-PET as a predictive marker for therapy with everolimus in metastatic renal cell cancer (mRCC).

e15047 Background: The oral mTOR inhibitor, everolimus, affects tumor growth by targeting cellular metabolic proliferation pathways and delays RCC progression. Yet most patients (pts) will not respond. Preclinical evidence suggests that elevated tumor glucose uptake as quantified by FDG-PET may predict anti-tumor activity. Methods: In this multicenter study, mRCC pts refractory to VEGF inhibition were treated with standard dose everolimus. FDG-PET scans were obtained at baseline and at 1 month; serial CT scans were obtained at baseline and every 8 weeks. Maximum standardized uptake value (SUVmax) of the most FDG avid lesion, the average SUVmax of all measured lesions and the corresponding one-month relative change were examined for association with 8-week change in tumor size. 60 pts were planned to provide 81% power (α=0.1) to detect a difference between a mean 20% vs. 10% increase in RECIST based tumor burden measurement in pts with low (SUVmax≤4) vs. high (SUVmax>4) FDG uptake. Results: 63 pts were enrolled; 51 were evaluable for primary endpoint of which 48 had both PET scans. Pt characteristics included: 46 (73%) clear cell histology, median age 61 (32 – 80), median number of prior systemic therapies 1.5 (1 – 4). Median pre- and post-treatment average SUVmax were 7 (1 –17.9) and 4.2 (1 – 13.9), respectively. Median relative change in average SUVmax was -21.2% (-59.8% – 0%). RECIST-based measurements demonstrated an average change in tumor burden of 0.3% (-32.0% – 35.9%) at 8 weeks, with 2 patients (4%) experiencing a PR. Among SUV measures considered, relative change in average SUVmax was the best predictor of change in tumor burden (all evaluable p=0.013; clear cell subtype p=0.031), but the overall correlation was modest (ρ = 0.36). Baseline SUV characteristics and low vs. high SUV classification were not associated with tumor response. Evaluation of progression and overall survival is pending. Conclusions: Systemic therapy with everolimus substantially decreased SUVs on follow-up PET scans in mRCC pts, but these changes were only modestly correlated with changes in tumor size. Correlation with survival metrics will be assessed. Clinical use of FDG-PET based biomarkers is challenged by high variability.

An evaluation of FDG-PET as a predictor of metabolic response to chemotherapy in metastatic colorectal cancer patients (mCRC).

e14057 Background: Limited information is available on the role of FDG-PET in the management of patients with mCRC. Bevacizumab prolongs overall survival and progression-free survival (PFS) when added to standard chemotherapy in mCRC patients. The purpose of the study was to explore the possible role of FDG-PET as response predictor for bevacizumab treatment in liver mCRC patients. Methods: Eighteen mCRC patients (7 women and 11 men), were treated with FOLFOX (n=12) or FOLFIRI (n=6) and bevacizumab (5 mg/kg). FDG-PET scans were performed before treatment (baseline) and median 15 days after cycle 5 (follow-up). PET scans were read by a nuclear medicine physician, blinded to the results of clinical parameters. The most representative liver lesion was used as target lesion. PET results were quantified by calculating the maximum standard uptake value (SUVmax) at baseline and follow-up. PFS was defined as the time from start of treatment to the date of first documented disease progression. Results: Median PFS was 10 months (95% CI: 8.51-11.49). The median baseline SUVmax was 5.18 (IQR: 3.61-8.42) and the median follow-up SUVmax was 2.93 (IQR: 2.15-5.94; p=0.025). Following the EORTC criteria, FDG-PET revealed a complete metabolic response in 8 patients (44%), partial metabolic response in 3 patients (17%), stable metabolic disease in 3 patients (17%) and progressive metabolical disease in 4 patients (22%). Correlation between metabolic response and radiological response according to RECIST was as follows: 6 of the 8 patients with radiological response had metabolic response (sensitivity 75%) and 5 out of 10 patients with radiological stable or progressive disease were metabolic non-responders (specificity 50%). Using the Cox proportional hazards model, the follow-up SUVmax (HR 1.33, 95% CI 1.000-1.776, p=0.05) showed a trend towards significant prediction of PFS. The Kaplan-Meier log rank test showed a PFS benefit for patients with >30% reduction in their SUVmax (p=0.02). Conclusions: The use of FDG-PET for therapy monitoring is clinically feasible and the follow-up SUVmax seems to be a promising predictor of PFS.

Indications et apport de la TEP au FDG dans les sarcomes de l’enfant en 2011

FDG-PET has boomed in recent years for diagnosis, staging and the search for recurrence of a large number of tumors. This is particularly true for soft tissue sarcomas and musculoskeletal sarcomas, for which the first publications on the potential role of FDG-PET dating back to the early 1990s. The majority of published studies on adult sarcomas confer, possibly a mixed population. Studies dedicated to pediatrics population are much rarer. The “Standards, Options and Recommendations” of the French Federation of Anticancer Centers published in 2003 on “The use of FDG-PET in oncology” and make recommendations and expert advices as part sarcomas of adult patients. After a first part dedicated to the particular interpretation of FDG PET in children, the purpose of this paper is to review the potential contribution of this exam in the treatment of pediatric sarcomas.

Abstract 1280: Preclinical and Clinical Evidence for MEK Pathway Inhibition by GDC-0973 using FDG-PET

Abstract Inhibitors of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) can cause potent growth arrest leading to tumor stasis or even regression, especially in BRAF mutant tumors. Seeking a pharmacodynamic marker of drug action, the effect of MEK inhibition on FDG PET signals was studied in rodent xenograft models using responsive and non-responsive cell lines. Colo205, HCT116, and A375 tumors showed substantial (30-50 %) signal (FDG flux, Ki, measured by a Patlak analysis) decreases within 72 h of beginning MEK inhibition and a rebound to baseline signal within 72 h of discontinuing treatment. BT474 tumors showed no effect. In MEK responsive tumors immunohistochemistry showed that glucose transporter GLUT1 redistributes away from the plasma membrane during treatment, which may explain the FDG PET findings. Fluorothymidine (FLT) uptake is also modulated by MEK inhibition, but the relative availability of clinical FDG PET centers and the robust preclinical results suggested the use of FDG PET, and not FLT PET, in clinic. FDG PET was implemented at all 4 Phase 1 study sites according to a standardized scanning charter. Scans were acquired at screening, at days 10-14 of cycle 1 (steady state drug concentration) and at days 26-28 of cycle 1 (trough drug concentration). Patients with RAS or RAF mutant tumors were treated at GDC-0973 MTD on the 21/7 and 14/14 dosing schedules. CT scans were acquired just prior to cycle 3 (∼ day 56) for response assessment. PET images were collected and read centrally. Up to 5 hypermetabolic lesions were assessed for mean and maximum standardized uptake value (SUV). A decrease of more than 20% in mean (across lesions) percentage change-from-baseline in SUVmax was considered a partial metabolic response (PMR). Compliance with the scanning guidelines across sites was generally good. Out of a total of 23 patients from both cohorts with PET scans read to date, 7 patients appeared to show a temporal profile of decreased FDG uptake at steady state with a rebound towards baseline at trough, mirroring the preclinical findings. Of 17 patients in the 21/7 MTD cohort whose PET scans were measured, 9 patients (∼53%) demonstrated a PMR at least one timepoint during cycle 1. Two of these patients demonstrated a PR per CT at 2 months (first tumor assessment) and also showed a robust PET response at both timepoints (Patient 1: -55% and -61% respectively; Patient 2: -63% and -53%). In addition, 2 other patients with a PMR at one or both timepoints had stable disease for at least 5 months. Of 6 patients in the 14/14 MTD cohort with PET scans read, 5 patients (83%) demonstrated a PMR at least one timepoint. Taken together, the preclinical PET evidence for a mechanistic effect of MEK inhibition on tumor glucose metabolism combined with the significant proportion of patients demonstrating PMR in this phase 1 study are consistent with hypothesis that GDC-0973 is achieving pathway modulation when given as single agent. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1280. doi:10.1158/1538-7445.AM2011-1280

FDG-PET-CT in pyrexia of unknown origin and inflammatory diseases

FDG-PET has been used successfully over the last decade for imaging patients with fever of unknown origin. Nowadays, PET-CT has become the standard in many centres although a limited number of prospective studies is available. This article summarizes the experience in the field and the potential use of FDG-PET in other inflammatory or immune diseases, such as sarcoidosis or rheumatoid arthritis.

Use of FDG-PET Imaging for Patients with Disseminated Cancer of the Appendix

The goal of this study is to evaluate the use of positron emission tomography (PET) in evaluation of patients with peritoneal dissemination of carcinoma of appendiceal origin (PDA). Thirty-three patients with PDA, who had preoperative PET or PET/CT imaging, were analyzed. Using operative, pathology, and PET +/- CT data, presence or absence of disease in each abdominal quadrant was noted and the use of 18fluoro-deoxy-glucose (FDG) PET for each quadrant was evaluated. The mean age was 52, and there were 17 males; 58 per cent had low-grade lesions. PET was positive in only 35 per cent of cases overall (30 and 41% sensitivity for low-grade and high-grade, respectively). PET without CT sensitivity for low-grade and high-grade lesions was 21 and 8 per cent, respectively. PET imaging has limited use for patients with PDA. We do not recommend the use of FDG-PET for patients with PDA from cancer of the appendix.

Best Practices: Consensus on Performing Positron Emission Tomography-Computed Tomography for Radiation Therapy Planning and for Therapy Response Assessment

The incorporation of positron emission tomography-computed tomography (PET-CT) into oncological imaging has expanded rapidly since the hybrid scanners were introduced approximately 10 years ago. PET-CT is becoming the standard of practice for the imaging diagnosis and staging of most cancers. Since its introduction, hardware-registered PET and CT images produced by a PET-CT scan were recognized as valuable not only for detection, staging and restaging applications but also for optimizing radiation treatment planning. Even before the introduction of PET-CT, the value of metabolic imaging with the use of FDG PET was recognized as a potentially powerful means of assessing response to various therapies, particularly chemotherapy regimens. To better understand the optimal use of PET-CT in radiation therapy planning and the role of PET-CT in assessing response to therapy, we invited experts from various disciplines to participate in focus group meetings that took place in 2009 and 2010. The Symposia focused on the use of PET-CT imaging in radiation therapy planning (2009) and the use of PET-CT in therapy response assessment (2010). This article will summarize areas of consensus reached by the group regarding many of the discussion topics. The consensus summaries covered in this article are meant to provide direction for future discussions on how to improve the application of this hybrid modality to optimize patient care.

Patterns of Use of FDG-PET for the Initial Staging of Follicular Lymphoma (FL) and Its Impact on Initial Treatment Strategy and Outcomes In the National Comprehensive Cancer Network (NCCN) Lymphoma Database

AbstractAbstract 81 Background:The management of follicular lymphoma (FL) can vary according to stage at presentation. The use of 18-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for initial staging of FL may result in upstaging and/or changes in treatment strategy. In this study, we describe the patterns of use of FDG-PET for the initial staging of patients with newly diagnosed FL and its potential impact on treatment. Methods:Data were obtained from the NCCN Non-Hodgkin's Lymphoma Outcomes Database, a prospective cohort study collecting comprehensive clinical, treatment, and outcome data for patients treated at 7 participating NCCN centers. Patients who presented between January 1, 2001 and September 30, 2009 with newly diagnosed low grade FL (grade 1, 2), received staging imaging within 6 weeks of diagnosis, and with at least 6 months of follow-up were included. We compared baseline and clinical characteristics as well as treatment among patients by receipt of FDG-PET for initial staging. Results:We identified 953 eligible FL patients with a mean age of 56 years; 532 (56%) underwent FDG-PET as part of initial staging. Use of FDG-PET varied significantly across NCCN centers (p<0.0001). Among patients who underwent FDG-PET for initial staging, 438 (82%) received early treatment (defined as treatment within 180 days of diagnosis) compared to 259 (61.5%) who were staged with conventional CT scanning only (p<0.0001).Among 189 patients with early stage FL (ESFL), 120 (63.5%) underwent FDG-PET for initial staging. Significant differences in use were observed across NCCN centers (p<0.0001). Of all ESFL, 55 (29.1%) were treated with radiotherapy (RT) alone, 68 (36%) with chemotherapy/immunotherapy (CIT) alone, 28 (14.8%) with combined RT and CIT and 38 (20.1%) were observed. Initial treatment strategy for ESFL varied significantly according to NCCN centers (p<0.001). Choice of initial treatment strategy for ESFL did not vary significantly by use of FDG-PET (p=0.09). Conclusions:The use of FDG-PET for staging of FL varies by center and is widespread despite a paucity of evidence supporting its use in this disease. Patients who undergo FDG-PET scan for initial staging appear more likely to receive early therapy although this may not be directly attributed to FDG-PET results. The management of ESFL is surprisingly heterogeneous and varies across NCCN centers but is not influenced by the use of FDG-PET scan at staging. Given the widespread use and high cost of FDG-PET, its clinical utility in ESFL should be further evaluated. Disclosures:No relevant conflicts of interest to declare.

Assessment of Therapy Response in Lung Cancer With 18F-α-Methyl Tyrosine PET

PET with a novel tracer, L-[3-¹⁸F]-α-methyl tyrosine (¹⁸F-FMT), has been studied in lung cancer. We evaluated ¹⁸F-FMT PET for therapy response in comparison with ¹⁸F-FDG PET. Eighteen patients with lung cancer underwent PET studies with ¹⁸F-FMT and FDG before and after chemoradiotherapy. Uptake of tracers was measured by standardized uptake value (SUV) in the primary tumor and the mediastinal lymph node. The ratio of the lymph node maximum SUV (SUV(max)) to that of the primary tumor and the SUV(max) of the primary tumor itself were correlated with the survival time estimated by Kaplan-Meier method. Metabolic response, as determined by the changes in the tracer uptake, was compared with Response Evaluation Criteria in Solid Tumors (RECIST) for therapy response. Agreement of therapeutic response evaluated by RECIST was noted in 10 (56%) of 18 patients evaluated with FDG PET and in 16 (89%) of 18 patients evaluated with ¹⁸F-FMT PET (p = 0.025). In nine patients with partial response, partial metabolic response was observed in eight (89%) by use of FDG PET and in nine (100%) by use of ¹⁸F-FMT PET. In nine patients with stable disease, stable metabolic disease was observed in two (22%) by use of FDG PET and in seven (78%) by use of ¹⁸F-FMT PET (p = 0.056). Fluorine-18-FMT PET revealed that the prognosis of the group with a lymph node-to-primary tumor SUV(max) ratio greater than or equal to 1 was significantly better than that in the group with a ratio of less than 1. Fluorine-18-FMT is a promising PET tracer for monitoring response to chemoradiotherapy and for predicting the prognosis of patients with lung cancer.

Impact of whole‐body 18F‐fluorodeoxyglucose positron emission tomography on therapeutic management of non‐small cell lung cancer

Accurate staging at the time of diagnosis is very important in deciding on the appropriate treatment for cancer patients. FDG PET indicates metabolic changes in cancer cells, enabling the early detection of lesions. This has the advantage of allowing more accurate staging than is possible with conventional staging tools, and has led to the incorporation of FDG PET in the initial work-up protocols for lung cancer patients. In this study, we evaluated the clinical impact of FDG PET as an initial staging tool, on the therapeutic management of patients with non-small cell lung cancer (NSCLC). Patients diagnosed with NSCLC by histopathology were retrospectively identified and both chest CT and FDG PET were performed for initial staging. Information was collected regarding the results of conventional versus FDG PET staging, and any resulting modifications of treatment were evaluated. Among the 537 patients who were evaluated FDG PET resulted in upstaging of the tumour in 91 (17%) and downstaging of the tumour in 68 (13%). Consequently, therapeutic management was modified in 118 patients (22%). Furthermore, use of FDG PET resulted in the detection of a second primary cancer in six patients. This study confirms that FDG PET has a considerable impact on the initial staging and therapeutic management of patients with NSCLC.

18-FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY AS A TOOL FOR RESPONSE PREDICTION IN SOLID TUMOURS

Current response guidelines for the treatment of solid tumours are based on CT criteria. Over the last decades new techniques have emerged to evaluate cancer therapy. FDG-PET scanning is a more functional imaging technique, which can measure differences in metabolic activity. Although it has a low specificity, studies show that it can outperform classical CT scanning criteria. Especially in lung, breast and oesophageal cancer it can predict response earlier in the neo-adjuvant setting. This could reduce the use of ineffective cancer therapies, reducing costs and patient toxicity, and direct patients sooner towards effective therapy. The main problem with FDG-PET remains the difficulty in defining thresholds for response, as there is clearly a lack in large prospective randomized studies validating the use of FDG-PET in response guidelines. We give an overview of data on response prediction in solid tumours by the application of PET.