Impact Of FDG-PET Research Articles

PD-0671 Impact of FDG PET in small-cell lung cancer patients treated with curative intent chemoradiotherapy

PD-0671 Impact of FDG PET in small-cell lung cancer patients treated with curative intent chemoradiotherapy

Impact of FDG-PET on therapy management and outcome ofdifferentiated thyroid carcinoma patients with elevated thyroglobulin despite negative iodine scintigraphy.

The objective of this study was to assess the impact of implementing FDG-PET imaging in treatment algorithms for differentiated thyroid cancer with suspected recurrence. Primary end points were overall, event-free and disease-specific survival. Secondary end points were therapies, disease control and the sensitivity and specificity of PET imaging. 194 patients with DTC treated at our center from 1996 to 2014 following thyroidectomy and routine 131I ablation with no remaining 131I uptake in whole-body scans but persisting or rising thyroglobulin values were enrolled in this retrospective analysis. Of these, 149 (76.8 %) received an 18F-FDG scan (PET group) whereas the remaining 45 patients (23.2 %) did not (non-PET group). Survival, disease-specific characteristics at inclusion, disease control and therapies were compared. Patients of the PET group generally showed characteristics associated with higher disease activity from inclusion onwards. This did not translate to statistically significant differences in survival. If PET imaging was performed following inclusion, patients received significantly less radioiodine treatments during the first nine months after inclusion (63.1 % of the PET-group vs 82.2 % of the non-PET group). Simultaneously, patients tended to receive more surgeries following PET imaging (27.5 % PET-group vs 13.3 % non-PET group). No significant differences regarding disease control were observed. The early use of FDG-PET imaging in cases of suspected recurrence or existence of dedifferentiated DTC can lead to changes in therapy management, specifically identifying patients unlikely to benefit from additional radioiodine therapy who would instead qualify for surgical therapy methods.

Impact of FDG-PET and Dynamic Contrast-Enhanced MRI in Comparison with DWI for N-Staging in Lung Cancer Patients

Background: Regarding mediastinal N-staging in lung cancer patients, computed tomography (CT), magnetic resonance imaging (MRI), and integrated 18Fluorine-fluorodeoxyglucose-positron emission tomography/CT (18F-FDG-PET/CT) are the most widespread imaging methodologies in clinical routine. Objectives: In order to further extract information from non-invasive staging, we evaluated the use of 18F-FDG-PET/CT and dynamic contrast enhanced (DCE) and diffusion-weighted imaging (DWI) MRI using histopathology as the diagnostic gold standard. Patients and Methods: A total number of 50 patients had undergone MRI of the chest within two weeks prior to surgery for histopathological proof. DCE-MRI was evaluated on the basis of region of interest (ROI)-based signal intensity/time (SI/T) curves in the respective mediastinal lymph nodes (LNs). In total, 28 LNs could be allocated to the corresponding histopathological findings, as well as to corresponding findings in 18F-FDG-PET/CT. Results: Malignant LNs presented with significantly higher FDG uptake in PET. Significant differences between malignant and benign LNs were found for DCE-MRI regarding the parameters MaxE, 4-minutes value, SE, EP and EP/MaxE. In DWI-MRI, malignant LNs presented with significantly lower signal intensity compared to benign LNs (p < 0.01). An apparent diffusion coefficient (ADC) threshold of 1528 mm2/s was found to exclude malignancy for LNs that are above the threshold. Conclusion: 18F-FDG-PET in addition with MRI that includes DWI might improve mediastinal N-staging, which is of interest in cases of FDG-equivocal LNs. An ADC threshold of 1528 mm2/s might potentially help to further classify LNs with indefinite PET-findings. DCE-MRI of mediastinal LNs seems not yet to be approved for clinical routine.

Impact of FDG-PET on the Detection of Patients with Lung Cancer at High Risk for ILD.

Idiopathic pulmonary fibrosis IPF is a type of interstitial lung disease (ILD) with poor prognosis. Lung cancer (LC) is a frequent complication in IPF, where all therapeutic options are potential triggers for acute exacerbation of IPF. Patients with 2-deoxy-2-fluoro-D-glucose-positron emission tomography/computer tomography (FDG-PET/CT) results before lobectomy for LC with and without (n=10 each) signs of ILD in initial imaging and after-care CT were retrospectively analyzed. FDG uptake was calculated as the maximum standardized uptake value (SUVmax) in the lung periphery divided by the SUVmax of the mediastinal blood pool (rSUVmax). Regional increase of fibrosis and ground-glass features in lobe-based CT analysis was used as standard reference. Patients with LC with ILD presented a significantly higher rSUVmax of 0.57 compared to patients without ILD with rSUVmax 0.47 (p<0.001). rSUVmax seems to be a valuable imaging surrogate in predicting patients with LC with increased risk for progressive ILD associated with thoracic surgery.

The utility of positron emission tomography in the treatment planning of image-guided radiotherapy for non-small cell lung cancer.

In the thorax, the extent of tumor may be more accurately defined with the addition of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to computed tomography (CT). This led to the increased utility of FDG-PET or PET/CT in the treatment planning of radiotherapy for non-small cell lung cancer (NSCLC). The inclusion of FDG-PET information in target volume delineation not only improves tumor localization but also decreases the amount of normal tissue included in the planning target volume (PTV) in selected patients. Therefore, it has a critical role in image-guided radiotherapy (IGRT) for NSCLC. In this review, the impact of FDG-PET on target volume delineation in radiotherapy for NSCLC, which may increase the possibility of safe dose escalation with IGRT, the commonly used methods for tumor target volume delineation FDG-PET for NSCLC, and its impact on clinical outcome will be discussed.

Place de la tomographie d’émission de positons (TEP) pour l’évaluation thérapeutique et le suivi du cancer du sein

Positron emission tomography (PET) with fluorodeoxyglucose (FDG) is a nuclear imaging method whose interest in oncology has only grown over the past fifteen years. This article summarizes the results in monitoring and therapeutic evaluation of breast cancer. For the search of locoregional or distant recurrence, the performance of FDG-PET are very interesting. The impact of FDG-PET on the therapeutic management is undeniable. For therapeutic evaluation, this imaging is useful to evaluate the neoadjuvant chemotherapy and hormonotherapy efficacy. FDG-PET is indicated in cases of suspected recurrence (clinical, biological or imaging suspicious). It is the most sensitive exam for the detection of bone or visceral metastases. It allows the re-staging during a relapse proved whether local or remote, and can change the therapeutic management.

Impact of FDG PET in optimizing patient selection for cytoreductive surgery in recurrent ovarian cancer

To investigate the impact of PET and PET/CT scanning on decision-making in management planning and to identify the optimal setting for selecting candidates for surgery in suspicious recurrent ovarian cancer. A retrospective chart review was performed in patients with possible recurrent ovarian cancer after primary optimal cytoreduction and taxane/carboplatin chemotherapy who had undergone FDG PET or FDG PET/CT scans from July 2002 to August 2008 to help make treatment decisions. The analysis included 44 patients who had undergone a total of 89 PET scans. The positive PET scans were classified as follows. (1) localized (one or two localized sites of FDG uptake), (2) multiple (three or more sites of FDG uptake), (3) diffuse (extensive low-grade activity outlining serosal and peritoneal surfaces). Of the 89 PET scans, 52 (58.4%) led to a change in management plan. The total number of patients in whom cytoreductive surgery was selected as the treatment of choice increased from 12 to 35. Miliary disseminated disease, which was not detected by PET scan, was found in 22.2% of those receiving surgery. Miliary disseminated disease was detected in 6 of the 12 patients with recurrent disease whose treatment-free interval (TFI) was <12 months, whereas none of those with a TFI of ≥12 months had such disease (P = 0.0031). PET or PET/CT is useful for selecting candidates for cytoreductive surgery among patients with recurrent ovarian cancer. To avoid surgical attempts in those with miliary dissemination, patients with a TFI of ≥12 months are the best candidates for cytoreductive surgery.

Impact of FDG-PET and -PET/CT Imaging in the Clinical Decision-Making of Ovarian Carcinoma: An Evidence-Based Approach

The most definitive role of fluorodeoxyglucose (FDG)-PET/computed tomography (CT) at present is surveillance and detecting recurrence in patients who have completed primary therapy but demonstrate a rising serum tumor marker (e.g., CA-125 levels). In this scenario, PET/CT demonstrates high sensitivity and accuracy in detecting lesions that are otherwise challenging, and appears superior (with less interobserver variability) compared with CT alone. Despite the fact that peritoneal deposits may be missed by PET/CT, the overall performance is better than CT alone. FDG-PET does not play a significant additional role in the primary diagnosis of ovarian cancers; however, the role of combined PET/CT modality has recently begun to be re-explored for initial disease staging, particularly because PET/CT can pick up small unsuspected lesions and thereby provide a better disease assessment of the whole body in a single examination. The baseline PET/CT also subserves an important role for future monitoring of therapy response. Therapy monitoring by PET could help to optimize neoadjuvant therapy protocols and to avoid ineffective therapy in nonresponders early in its course, although PET/CT has cost-effectiveness issues that need further evaluation. The prognostic value of FDG-PET/CT has been investigated in the following areas: in the preoperative setting to predict optimal cytoreduction; to assess the value of a positive FDG-PET following primary surgery; and when employed as a replacement for second-look laparotomy following completion of primary surgery and chemotherapy. The data, although promising, are still sparse in all the three domains for a definite recommendation.

Baseline Staging Evaluation in Lymphoma: The Role of FDG PET, CT, and Bone Marrow Biopsy

Abstract 2640 BACKGROUND:The revised response criteria for malignant lymphoma (Cheson et al JCO 25:579 2007) incorporated FDG PET for determination of response. This was strongly recommended for patients with curable lymphomas (diffuse large B-cell lymphoma [DLBCL] and Hodgkin lymphoma [HL]). For incurable lymphomas PET was not recommended unless response was a major trial endpoint. Part of the reservation regarding the use of PET for response evaluation in incurable lymphomas was based on the potential variability in FDG avidity at baseline. This retrospective review was performed to understand the frequency of FDG avidity across a range of lymphoma histologies and compare diagnostic yield to CT. Furthermore, diagnostic utility of bone marrow biopsy was evaluated in patents with DLBCL and HL compared to identification of disease by FDG PET and CT scan. METHODS:After obtaining a waiver of authorization from the MSKCC Institutional Review Board patients the DAVInCI data mining tool was used to retrospectively identify patients with the diagnosis of lymphoma who had both a FDG-PET scan and CT at diagnosis available in the PACS. Either the FDG-PET or the CT had to be informative (which excluded patient with CS I resected disease). The sites of disease were recorded for PET (including SUVs) and for CT. The impact on the CS at diagnosis was determined. DLBCL and HL patients with bone (B) or bone marrow (BM) involvement were identified by being positive on any one modality: BM biopsy; FDG-PET; or CT. RESULTS:Data, including imaging, from 522 incident cases of lymphoma were reviewed. FDG PET performed for lymphoma at initial diagnosis demonstrated FDG-avid disease in 97.3% (508/522) of cases; there was some variability across histologies (Table 1). There was a strong correlation between CT and PET. PET identified more disease in 0–32.3% of cases depending on histology and CT was more informative in 3.2–33.3% of cases. CT tended to be more informative where the median SUV of PET was relatively low (SLL, MZL, MCL). The impact of FDG PET on Ann Arbor stage was modest but was greatest for SLL and T-cell lymphoma (Table 1, Change Stage).Table 1:Comparison of FDG-PET and CT in Lymphoma at DiagnosisDiseasePET +/TOTAL (%)SUV MAX RangeSUV MAX MedianLess on CT (%)More on CT (%)Change Stage (%)DLBCL192/196 (98%)2.2–84.019.240 (21.2%)15 (7.9%)9 (4.8%)HL111/112 (99.1%)3.5–33.811.524 (22%)6 (5.5%)5 (4.6%)MCL37/38 (97.4%)2.4–18.26.852 (5.3%)5 (13.2%)1 (2.6%)FL60/65 (92.3%)2.9–26.810.114 (22.6%)7 (11.3%)6 (9.8%)MZL43/44 (97.7%)1.0–17.66.56 (13.6%)6 (13.6%)1 (2.3%)BL29/30 (96.7%)2.3–36.813.47 (23.3%)3 (10.0%)3 (10.0%)SLL5/6 (83.3%)2.7–13.57.602 (33.3%)1 (16.7%)T-Cell31/31 (100%)0.9–27.610.710 (32.3%)1 (3.2%)5 (16.1%)Identification of bone (B) and bone marrow (BM) disease in HL and DLBCL was examined. 57 patients with DLBCL were found to have B/BM involvement by BM, CT, or PET. PET was the most sensitive test for B/BM disease (50/57 88%). CT identified bone disease in 33/37 (58%) of cases but these were strictly a subset of the PET positive cases. However, BM biopsy identified involvement in 7 (15.2%) cases which were negative by PET. For HL, 20 patients were found to have B/BM disease. FDG PET identified all 20 cases, CT 12 cases and BM biopsy only 3. CONCLUSIONS:FDG-PET is positive in baseline in 97% of cases of lymphoma across all histologies. However, there is discordance between CT and PET in 28% of cases. Therefore, for clinical trials baseline contrast enhanced CT and FDG-PET are both necessary at baseline to full identify sites of disease. Outside the setting of a clinical trial, clinical discretion should be used in choosing the appropriate pre-treatment imaging. In the case of B/BM disease FDG-PET was the most informative modality in DLBCL and HL. However, bone marrow biopsy remains an essential part of the diagnostic evaluation of DLBCL since 7/20 bone marrow positive cases were not identified on FDG-PET or CT. The utility of the bone marrow biopsy in HL was questionable as FDG PET identified all cases of B/BM disease. Disclosures:No relevant conflicts of interest to declare.

Impact of FDG-PET in suspected recurrent ovarian cancer and optimization of patient selection for cytoreductive surgery

Impact of FDG-PET in suspected recurrent ovarian cancer and optimization of patient selection for cytoreductive surgery

Utility of Positron Emission Tomography Imaging in Lymphoma: A Clinician's Point of View

Positron emission tomography (PET) using fluorine-18 (FDG) is increasingly used in the staging of lymphoma. Results of the use of PET during and after completion of therapy for staging of Hodgkin’s lymphoma and aggressive non-Hodgkin’s lymphoma demonstrate a highly predictive value for outcome. Based on recommendations of the International Harmonization Project, FDG-PET has been incorporated into the revised response criteria of lymphoma. There is currently no evidence to support the use of FDG-PET in indolent lymphoma, nor for its routine use during follow-up. Evidence also lacks on the impact of FDG-PET on treatment outcome. Clearly, well designed clinical trials are warranted to determine the subsets of patients that will benefit from this modality.

Impact of FDG PET on the management of TBC treatment

The aim of this study is to assess the potential impact of double-phase FDG PET versus routine staging in HIV-negative patients suffering from tuberculosis.16 consecutive patients suffering from tuberculosis underwent contrast-enhanced CT and double-phase FDG PET imaging (45 min, 120 min). Early (E) and delayed (D) SUVmax values were determined for all identified lesions and % change in SUV calculated (DeltaSUV).Seven patients presented with lung lesions on PET as well as CT (mean SUVmaxE 8.2, mean SUVmaxD 11.1, (p = 0.002), DeltaSUV 35%. In two patients, lesions were judged as non-active on CT. In nine patients, 18 sites of LN involvement were identified on both early and delayed FDG PET images (mean SUVmaxE 6.3, mean SUVmaxD 7.9, (p = 0.0001), DeltaSUV: 25%). 9 out of 18 sites of LN involvement, occurring in five patients, were missed on CT. In four of these five patients, sites of LN involvement were the only sites of extra-pulmonary involvement identified. In 6 out of 16 patients, pleural involvement was identified, respectively in 5 on FDG PET and in 6 on CT imaging (mean SUVmaxE 1.3, mean SUVmaxD 1.7, (p = 0.06), DeltaSUV 21%). In 4 patients, osseous involvement was identified by both FDG PET and CT (mean SUVmaxE 7.2, mean SUVmaxD 10.7, (p = 0,06), DeltaSUV 45%). Finally, in 3 patients, joint involvement was identified on both FDG PET as well as on CT imaging (mean SUVmaxE 4.7, mean SUVmaxD 5.2, DeltaSUV 23%). FDG PET did not identify CT-additional sites of involvement that would have resulted in a prolonged treatment.In HIV-negative patients suffering from tuberculosis, FDG PET images suggested a more extensive involvement by Mycobacterium tuberculosis when compared to contrast enhanced CT.

Impact of PET on the Radiation Treatment of Hodgkins Lymphoma

Hodgkins lymphoma (HL) is a lymphoproliferative malignancy that frequently affects young people. Because patients with HL are often cured, this neoplasm serves as a clinical laboratory for investigating the late effects of cancer therapy. The “hot” issues today are, in advanced stages, how to identify the best strategy to reduce the rate of resistant diseases and, in the early stages, how to minimize late toxicity due to both chemotherapy and radiotherapy (RT). Literature data revealed that PET as a very promising tool in the management of HL. The main applications of FDG-PET in HL are in staging, therapy monitoring, response assessing and follow-up. Recent data show that early PET seems to play a role in predicting the treatment outcome. In RT FDG-PET improves the accuracy in the disease localization and staging with changes in radiation treatment planning in one third of patients with early-stage HL. It also reduces the subjectivity in lymphoma RT field determination, one of the major causes of uncertainty in radiation treatments. The impact of FDGPET will be greater as more conformal RT is planned. In conclusion, the highly curable early stage Hodgkin lymphomas require careful evaluation and balance of the available treatments, in order to achieve a really individualized solution, reducing radiation doses and/or fields dimension and using new advanced techniques.

Impact of 18F-flurodeoxyglucose positron emission tomography in the staging and treatment response assessment of extrapulmonary small cell cancer

e14639 Background: To assess the frequency of use and impact of FDG PET in the management of extrapulmonary small cell carcinoma (EPSCC). Methods: Patients treated for EPSCC who had undergone FDG PET for staging or response assessment between 1985 and 2007 were identified from the institutional database and patient records. The PET result was compared to the conventional staging investigations and management decisions were recorded. Results: 22 patients had staging PET at diagnosis. All known disease was PET avid. Stage migration occurred in one patient. Additional disease without upstaging was noted in 3 patients. PET influenced management in 4/22 (18%) of cases, in one case changing from radical to palliative therapy, and in 3 cases altering radiation target volume. 21 patients had reassessment PET scans. There was disparity with conventional imaging in 8 cases. In 4 cases the PET was found to be correct, in 2 case the PET result was a false positive and 2 cases were not assessable. (Sensitivity 100%, specificity 80%.) PET resulted in a change in management in 25% of patients, in all cases discontinuing radical therapy in patients with persistent disease. Conclusions: PET contributes to both staging and restaging of EPSCC and may influence management in up to 25% of cases. No significant financial relationships to disclose.

Place de la TEP au FDG dans le bilan des épilepsies pharmacorésistantes

The work-up of drug-resistant partial epilepsy is intended to localize epileptogenic foci in the purpose of a possible surgery. We aimed to assess the role of fluorodeoxyglucose Positron Emission Tomography (FDG PET) in this scope. This study involved 34 patients who underwent brain FDG PET, with a final diagnosis in 21. The value of FDG PET for lateralisation and localisation of the epileptogenic focus was evaluated by a blinded interpretation, and compared with the value of standard investigations. The impact of FDG PET was assessed by the means of a questionary intended for the neurologist in each case. All the epilepsy types together, FDG PET lateralised and localised the foci in 65 and 47% of the 34 subjects respectively. Among the 19 subjects with final diagnosis (patients with bilateral foci excluded), lateralisation was correct in 84% and localisation in 63% (and the values were greater for temporal epilepsy than for extratemporal foci). PET frequently provided additional information compared with MRI, but not with EEG. FDG PET was useful in 82.5% of cases (confirming management in 65% and changing it in 17.5% of the patients). Our experience corroborated the value of FDG PET for lateralisation and localisation of epileptogenic foci, and its role in case of normal MRI. However, FDG PET appears as a confirmation tool rather than an examination resulting in a change in management rate.

The Impact Of Fdg-pet For The Preoperative Management Of Patients With Colorectal Cancer.

Amac: Tum vucut fluorodeoksiglukoz pozitron emisyon tomografi (FDGPET) goruntulemenin rekurren kolorektal kanser (KRK) tanisindaki ve kanser tedavisine yanitin takibindeki rolu kanitlanmistir. Fakat KRK’in FDGPET ile preoperatif degerlendirilmesinin tedavi secimine katkisi ile ilgili az sayida calisma mevcuttur. Bu calismada FDG-PET’in KRK’li hastalarda, preoperatif donemde, hasta yonetimine katkisini arastirdik. Gerec ve Yontemler: Bu prospektif calismaya, histopatolojik veya yuksek klinik suphe ile KRK tanisi almis, 26 ardisik hasta (16 erkek, 10 kadin) dahil edildi. Tum hastalar bilgisayarli tomografi (BT) ve FDG-PET ile degerlendirildi. Histopatolojik veya klinik takip bulgulari esas alinarak FDG-PET sonuclari BT sonuclari ile karsilastirildi. Bulgular: FDG-PET primer kanseri saptamada %96 duyarliliga ve %100 pozitif ongoru degerine sahipken BT’de bu degerler sirasiyla %68 ve %95 idi. FDG-PET ilave metastatik hastaligi saptamada %89 duyarlilik ile BT’ye (%33) ustunluk gostermekteydi. FDG-PET 8 hastanin tedavi seciminde degisiklige neden olarak olumlu katki yapti, bunlardan 3’unde gereksiz cerrahiden kacinilmis oldu. Sonuc: FDG-PET’in KRK’in tanisinda ve evrelemesinde yuksek duyarlilik gosterdigi sonucuna varilmistir. BT ile birlikte kullanimi kuratif amacli cerrahi islem planlanan hastalarin daha dogru sekilde secilmelerine olanak saglar.

Impact of FDG-PET to detect recurrence of head and neck squamous cell carcinoma

Impact of FDG-PET to detect recurrence of head and neck squamous cell carcinoma

Impact of FDG PET on the preoperative staging of newly diagnosed breast cancer

The main objective of this study was to determine the efficacy of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) to assess the impact of this technique in staging of patients with newly diagnosed breast cancer. Two hundred and seventy-one consecutive patients (median age = 51 +/- 11 years) with biopsy-proven primary breast cancer who were examined by FDG PET were enrolled in this prospective preoperative staging study. Whole-body FDG-PET images were acquired approximately 60 min after the intravenous administration of FDG (5.2 MBq/kg). Visual assessment and the maximum standardized uptake value (SUVmax) of breast lesions for semiquantitative analysis were carried out. The PET results were compared with the histopathology results. For the tumor, node, metastases (TNM) staging, 240 patients (250 breasts) were considered eligible based on the criteria that were established for this analysis. Significant differences were noted in SUVmax of lesions according to the TNM staging (p < 0.05). The average SUVmax of the primary tumor was calculated in patients with axillary involvement (n = 58) and for the ones without axillary metastasis (n = 79), and SUVmax were 4.1 +/- 3.5 and 2.8 +/- 2.3, respectively, with a significant difference between the two groups (p = 0.03). PET imaging revealed pathological FDG uptake in 54% (46/85) of patients with axillary lymph node metastases. The sensitivities of FDG PET for detecting axillary lymph node metastasis were found 41% in pN1, 67% in pN2, and 100% in pN3, and the specificity was 89% for pN0 stage. Detection of extra-axillary regional node or distant metastatic lesions revealed by PET scan in 22 of 24 patients resulted in a significant change in the TNM stage. Distant metastasis without axillary lymph node metastasis was noted in 21% (5/24) of patients. The results revealed that FDG PET upgraded TNM stage in 9.2% (22/240) of patients and 7.5% (18/240) of patients were diagnosed as having one or more distant metastases. FDG PET was able to identify extra-axillary regional nodal and distant lesions in newly diagnosed patients with breast cancer; FDG PET may alter the staging and management of therapy in patients with newly diagnosed breast cancer.

Intérêts et perspectives de la TEP-TDM en sénologie : revue de la littérature

18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a technique of functional imaging whose interest in oncology does not cease growing. This article summarizes the results of the technique in senology. For the initial evaluation of locally advanced breast cancer (extended primitive lesion, axillary lymph nodes...), the FDG-PET makes it possible to evaluate lymph nodes (in particular internal mammary nodes) and to seek remote metastases. The sensitivity of the examination appears nevertheless low for the secondary lesions of small size and for bone metastases of osteoblastic form, for which the performances of the bisphosphonates scintigraphy are higher. For the search of a loco-regional or remote recurrence, the performances of FDG-PET are very interesting, including in the event of normality of the biological assessment. The impact of FDG-PET on the therapeutic strategy is undeniable and seems estimated at least 20%. FDG-PET is not recommended for the characterization of a breast lesion. In addition to the small tumoral size, the causes of false negative are mostly represented by the lobular histological form, by the tumours with low proliferation, the tumours of low grade and the well differentiated lesions. The causes of false positive are mainly in relation with inflammatory and/or infectious phenomena. For similar reasons, FDG-PET cannot replace the anatomy-pathological analysis of the axillary nodes. To evaluate the effectiveness of a neo-adjuvant chemotherapy, FDG-PET seems to be a powerful examination. Nevertheless, the data of the literature appear insufficient to recommend it in current practice. It is the same way for the prognostic interest.

Utility of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the staging, radiotherapy planning and prognostication of anal cancer

4559 Background: Accurate inguinal and pelvic nodal staging in anal cancer is important for prognosis and planning of (chemo)radiation fields. There is strong evidence for the impact of FDG-PET in staging and management of cancer, with early reports of an increasing role in outcome prognostication for a number of tumours. We aimed to determine the impact of FDG-PET on the nodal staging, radiotherapy planning and prognostication of patients with primary anal cancer. Methods: Sixty-two consecutive patients with anal cancer referred to a single tertiary oncology centre between August 1997 and November 2005 were staged with conventional imaging (CIm), computed tomography, magnetic resonance imaging and chest x-ray and by FDG-PET. The stage determined by CIm and the proposed management plan was prospectively recorded and changes in stage and management as a result of FDG-PET assessed. Patients were treated using uniform radiotherapy technique and dose. The accuracy of changes and prognostication of FDG-PET was validated by subsequent clinical follow-up. Kaplan-Meier survival analysis was used to assess survival for the cohort and by FDG-PET and CIm stage. Results: The TNM stage group was changed in 23% (14/62) as a result of FDG-PET (15% up-staged, 8% down-staged). Fourteen percent of T1 patients (3/22), 42% of T2 patients (10/24) and 38% of T3–4 patients (6/16), assessed using CIm, had a change in their N or M stage following FDG-PET. Sensitivity for nodal disease by FDG-PET and CIm was 92% and 72% respectively. The staging FDG-PET scan altered management intent in 3% (2/62), and altered radiotherapy fields in 13% (8/62). Estimated 5 year overall survival and progression free survival (PFS) for the cohort was 77.3% (95% CI 55.3%-90.4%) and 72.2% (95% CI 51.5%-86.4%) respectively. Estimated 5 year PFS for FDG-PET and CIm staged N2–3 disease was 70% (95% CI 42.8%-87.9%) and 55.3% (95% CI 23.3%-83.4%) respectively. Conclusions: FDG-PET shows increased sensitivity over CIm for staging nodal disease in anal cancer and changes treatment intent or radiotherapy fields in a significant proportion of patients. Improved 5 year PFS for FDG-PET staged N2–3 disease could be consistent with more accurate nodal staging and radiotherapy targeting. No significant financial relationships to disclose.