Prognostic value of functional tumor burden on 68Ga-DOTATOC PET/CT in patients with pancreatic neuro-endocrine tumors.

Despite their relative quiescence, pancreatic neuro-endocrine tumors (pNET) can correspond to various presentations and outcomes. Several prognostic factors have been identified, including maximal standardized uptake value of the most intense focus (maxSUVmax) on Positron Emission Tomography (PET) with a somatostatin analogue. Herein, we investigate the prognostic value on progression free-survival of the total functional tumor volume (TFTV) measured by 68Ga-DOTATOC PET. From patients who underwent 68Ga-DOTATOC PET from 2008 to 2014, we selected consecutive patients with G1 or G2 pNET (2010 World Health Organization classification), at least one abnormal focus on PET and available follow-up data. TFTV was computed by summing the volumes of all pathological foci, delineated use of 41% of its SUVmax for each threshold focus. Fifty patients were included. During the follow-up period, 33 patients had stable or responsive disease (66%; median duration 28.5 months; range 6.3-77.7 months) and 17 patients experienced disease progression (34%; median progression time 21 months; range 6.7-44.7 months). Median PFS was 43.5 months. The best TFTV cut-off for predicting progression within 24 months was 13.8 cm3. Multivariate analysis determined that TFTV greater than 13.8 cm3 was the only criterion considered a significant risk factor for tumor progression (HR 2.9; p=0.0003). A significant difference in PFS was observed for TFTV (<13.8 vs. ≥ 13.8 cm3: median not reached vs. 25 months; p=0.0001). Our study suggests that 68Ga-DOTATOC TFTV measured on PET images is a valuable prognostic biomarker in patients with well-differentiated pNETs of all stages.

18-F fluorodeoxyglucose positron emission tomography indicating unsuspected infections in two patients with dermatomyositis.

Dermatomyositis is an idiopathic inflammatory myopathy that may be associated with malignancies. The technique of 18-F fluorodeoxyglucose (FDG)-positron emission tomography (PET) is an important tool to investigate underlying malignancy in patients with a possible paraneoplastic syndrome. We report two consecutive patients with dermatomyositis in whom 18-F FDG-PET revealed unsuspected infections. Physicians should be aware that a positive 18-F FDG-PET is not specific for malignancy and may reveal other conditions including an infectious disorder.

Prospective comparison of FDG and FET PET/CT in patients with head and neck squamous cell carcinoma.

AIM: The clinical usefulness of 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) in head and neck squamous cell carcinoma (HNSCC) is now well-documented. However, its sensitivity is greater than its specificity due to false-positive results in inflammatory or infectious lesions, which are frequent in this area, in particular after treatment by surgery and/or radiotherapy. O-2-fluoro-(18F)-ethyl-L-thyrosine (FET) has been reported not to be taken up by such lesions, and a preliminary study indicated that this may be clinically useful in HNSCC. We performed a prospective study to compare the diagnostic performances of FDG and FET PET/CT in the different settings of HNSCC. MATERIALS AND METHODS: Twenty-seven patients (20 men and seven women, aged 48-76, among 30 patients included) and 69 suspected cancer sites are now evaluable on basis of postsurgical histology and/or follow-up greater than 6 months; 15 patients were referred for initial staging and 12 during posttherapy follow-up, a recurrence being suspected in eight of them. FDG and FET PET/CT were performed on two different days, the patient fasting for 6 h, 1 h after injection of 5 MBq/kg of body mass of each radiopharmaceutical. Both PET/CT examinations were blind read more than 6 months after the end of inclusions in a random order for each tracer and with a time interval greater than 1 month between FDG and FET PET/CT blind readings. RESULTS: Overall diagnostic performances, derived from blind reading: FDG PET/CT on a per patient basis: sensitivity 100%, specificity 71%, accuracy 93%; FDG PET/CT on a per site basis: sensitivity 95%, specificity 63%, accuracy 83%; FET PET/CT on a per patient basis: sensitivity 70%, specificity 100%, accuracy 78%; FET PET/CT on a per site basis: sensitivity 64%, specificity 100%, accuracy 78%. At site level, sensitivity was significantly greater with FDG (p<0.02) and specificity with FET (p<0.01). The statistical level of significance was not reached at patient level. CONCLUSION: Although its good specificity was confirmed, FET did not appear to be suited as a first-line PET tracer in HNSCC imaging and cannot replace FDG for staging due to insufficient sensitivity. However, it was useful in a few selected cases to favor a wait and see attitude when a FDG+ FET- focus was discovered in patients referred for systematic FDG PET during follow-up. In contrast, second primary cancers should not be ruled out if FDG was clearly positive in the lungs or the digestive tract.

Pathology underrates colon cancer extranodal and nodal metastases; ex vivo radioimmunodetection helps staging.

PURPOSE: Colorectal carcinoma is frequently accompanied by small lymph nodes metastases that often escape pathologic examination. We evaluated whether ex vivo radioimmunodetection with the Affinity Enhancement System (AES) could improve detection of mesocolonic metastases. EXPERIMENTAL DESIGN: A bivalent 111In-labeled hapten was injected (16 patients) 4 days after a bispecific antibody (anticarcinoembryonic antigen, antihapten). Surgery was done 1 to 3 days later, and radioactive uptake in the mesocolon was recorded. Extensive pathologic examination of the mesocolon (reference method) was done after fat dissolution. This method visualizes all lymph nodes but is not in routine use. RESULTS: The reference method disclosed 705 nodes. There was no significant difference between the number of node metastases detected by AES or by the reference method (16 versus 17). Better detection would have been obtained by AES than by routine pathology (P<0.01). In addition 12 extranodal metastases were found in this study of which eight were detected by AES. The prognostic importance of such extranodal metastases has been underlined in the literature. Routine pathology combined with AES would have disclosed all node metastases and 86% of total metastases versus 35% by routine pathology alone. CONCLUSIONS: Ex vivo radioimmunodetection could improve nodal and extranodal metastases detection in patients with colorectal cancer. Its value for improving pathologic analysis, together with the effect of these small metastases on prognosis, should be further evaluated. The benefit of adjuvant chemotherapy for patients upstaged with radioimmunodection should also be assessed because adjuvant chemotherapy improves the 5-year survival of stage III patients.

[Imaging and PET-CT of adult and childhood lymphoma]. / Imagerie radiologique et TEP scanner des lymphomes de l'adulte et de l'enfant.

Malignant lymphomas are lymphoproliferative disorders arising in both lymphoid tissue and non-lymphoid organ systems. Treatment rarely is surgical, and currently relies on a combination of chemotherapy and radiation therapy. The role of imaging is to determine the spread of the disease, to identify targets and to assess therapeutic response. Imaging techniques mainly use morphological criteria, and may underestimate infiltrative disease, as observed in bones. The frequent presence of residual masses after treatment usually prevents classification of patients as complete response. Over time, positron emission tomography (PET) with F18-fluorodeoxyglucose (FDG) has become a prominent part of the workup at diagnosis and during follow-up. Recently, PET has been integrated in the revised response criteria for malignant lymphoma.

[18F-FDG PET and bone scintigraphy to search for bone metastasis of lung cancer]. / TEP au FDG-(18F) et scintigraphie du squelette dans la recherche de métastases osseuses du cancer broncho-pulmonaire.

Initial staging of lung cancer is essential to determine the appropriate therapeutic strategy. 18F-FDG PET is currently considered to be the gold standard. 99mTc bisphonate bone scintigraphy has long been indicated to search for bone metastases but it is not know whether this exploration adds further information after an 18F-FDG PET scan. In order to answer this question, two observers unaware of the clinical situation reread PET scans and bone scintigraphies and results compared with other imaging findings. Between February 2001 and March 2004, 39 patients (13F, 26M, 62 +/- 11 yr) underwent 18FFDG PET and bone scintigraphy (mean interval 17 +/- 17 d). When the two explorations agreed for the diagnosis of bone extension, we considered that bone scintigraphy added nothing. When the two explorations were in disagreement, the other imaging examinations, the clinical features and laboratory results during the five-month minimal follow-up were used to establish the reference diagnosis. 18F-FDG PET and bone scintigraphy were in agreement in 29 patients (74%) with positive results in 12 (31%) and negative results in 17 (43%). The two explorations were in disagreement in 10 patients (26%). Among the five disagreement cases with positive bone scintigraphy and no bone anomaly on the 18F-FDG PET, the anomalies were benign and explained by clinical features (3 patients) or were not confirmed by the clinical course and laboratory results (2 patients). Among the 5 cases with a bone anomaly on the 18F FDG PET, no metastasis could be identified during clinical follow-up. Bone scintigraphy does not enable identification of any bone metastases which were not recognized on the PET scan and therefore should not be performed systematically. Using a computed tomography scan with the 18F-FDG PET could further limit the contribution of bone scintigraphy by providing more precision concerning foci identified on the PET scan.

Best sensitivity of 18F-FDOPA PET/CT to detect metastasis in one case of neuroendocrine tumour of the ileum. / Mejor rendimiento de la PET/TC con 18F-FDOPA para la detección de metástasis de un tumor neuroendocrino del íleon.

Neuroendocrine tumours (NET) are heterogeneous and frequently spread over the body, making their imaging difficult. With this aim, nuclear medicine imaging, using PET or SPECT with different tracers, has been proposed for decades, but there is currently no consensus on the most appropriate technique, even when only considering gastrointestinal NET. The case is presented of a 67year old woman with a well differentiated NET of the ileum with suspected recurrence, which was not detected by any imaging technique except 18F-FDOPA PET/CT. Subsequent follow up showed disease progression, which confirmed the true positivity of 18F-FDOPA. Using this case, we discuss and compare different radiotracers for the diagnosis of gastrointestinal NET, focusing on those embryologically originating from the mid-gut.

6-[F-18]fluoro-L-DOPA positron emission tomography in the imaging of Merkel cell carcinoma: preliminary report of three cases with 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography or pentetreotide-(111In) SPECT data.

PURPOSE: Merkel cell carcinoma (MCC) is an uncommon and aggressive cutaneous neoplasm of neuroendocrine origin. Somatostatin receptor scintigraphy (SRS) and positron emission tomography (PET) using 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) have been proposed to stage MCC and to detect early recurrences. As 6-[F-18]fluoro-L-DOPA (FDOPA) is taken up by other neuroendocrine tumors, we speculated that FDOPA-PET could image MCC. PROCEDURE: FDOPA-PET was performed together with FDG-PET (three patients) and SRS (two patients) in different clinical settings: localization of the primary tumor, staging, and suspicion of recurrence. RESULTS: Uptake of FDOPA-(18F) by MCC was observed in the two true-positive cases, with an agreement between the results of FDOPA-PET, FDG-PET, and SRS; however, the contrast was lower on FDOPA-PET than on FDG-PET images. In the last patient suspected of recurrence repeatedly on SRS and with inconclusive FDG-PET, FDOPA-PET was negative, and a 12-month follow-up demonstrated a true-negative result. CONCLUSION: MCC takes up FDOPA-(18F). The potential role of FDOPA-PET in its management warrants clarification.

[Impact of computed tomography (CT) and 18F-deoxyglucose-coincidence detection emission tomography (FDG-CDET) image fusion for optimisation of conformal radiotherapy in non-small-cell lung cancers]. / Tomographie par émission de positons et détection en coïncidence (TEDC) et recalage d'images de simulation virtuelle par tomodensitométrie. Impact sur la planification de la radiothérapie conformationnelle des cancers bronchiques non à petites cellules.

UNLABELLED: To report a retrospective study concerning the impact of fused 18F-fluorodeoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on three-dimensional conformal radiation therapy (3D-CRT) planning for patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: One hundred and one patients consecutively treated for stages I-III NSCLC were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define target volume. RESULTS: FDG-PET identified previously undetected distant metastatic disease in 8 patients making them ineligible for curative CRT (one patient presented some positive uptakes corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because fused CT/PET images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT/PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was > or = 25% in 7 patients because CT/PET image fusion reduced pulmonary GTV in 6 patients (3 patients with atelectasis) and mediastinal nodal GTV in 1 patient. The GTV increase was > or = 25% in 14 patients due to an increase of the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Among 81 patients receiving a total dose > or = 60 Gy at ICRU point, after CT/PET image fusion, the percentage of total lung volume receiving more than 20 Gy (VL20) increased in 15 cases and decreased in 22 cases. The percentage of total heart volume receiving more than 36 Gy increased in 8 patients and decreased in 14 patients. The spinal cord volume receiving at least 45 Gy (2 patients) decreased. After multivariate analysis, one single independent factor made significant effect of FDG/PET on the modification of the size of the GTV: tumor with atelectasis (P = 0.0001). Conclusion. - Our study confirms that integrated hybrid PET/CT in the treatment position and coregistered images have an impact on treatment planning and management of patients with NSCLC. FDG images using dedicated PET scanners with modern image fusion techniques and respiration-gated acquisition protocols could improve CT/PET image coregistration. However, prospective studies with histological correlation are necessary and the impact on treatment outcome remains to be demonstrated.

[Impact of computed tomography (CT) and 18F-deoxyglucose positron emission tomography (FDG-PET) image fusion for conformal radiotherapy in esophageal carcinoma]. / Tomographie par émission de positons et fusion d'images de simulation virtuelle par tomodensitométrie. Impact sur la planification de la radiothérapie conformationnelle des cancers de l'oesophage.

PURPOSE: To study the impact of fused (18)F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on conformal radiation therapy (CRT) planning for patients with esophageal carcinoma. PATIENTS AND METHODS: Thirty-four patients with esophageal carcinoma were referred for concomitant radiotherapy and chemotherapy with radical intent. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. PET-images were coregistered using five fiducial markers. Target delineation was initially performed on CT images and the corresponding PET data were subsequently used as an overlay to CT data to define the target volume. RESULTS: FDG-PET identified previously undetected distant metastatic disease in 2 patients, making them ineligible for curative CRT. The Gross Tumor Volume (GTV) was decreased by CT and FDG image fusion in 12 patients (35%) and was increased in 7 patients (20.5%). The GTV reduction was >or=25% in 4 patients due to reduction of the length of the esophageal tumor. The GTV increase was >or=25% with FDG-PET in 2 patients due to the detection of occult mediastinal lymph node involvement in one patient and an increased length of the esophageal tumor in the other patient. Modifications of the GTV affected the planning treatment volume (PTV) in 18 patients. Modifications of delineation of GTV and displacement of the isocenter of PTV by FDG-PET also affected the percentage of total lung volume receiving more than 20 Gy (VL20) in 25 patients (74%), with a dose reduction in 12 patients and a dose increase in 13 patients. CONCLUSION: In our study, CT and FDG-PET image fusion appeared to have an impact on treatment planning and management of patients with esophageal carcinoma related to modifications of GTV. The impact on treatment outcome remains to be demonstrated.

(68)Ga-AMBA and (18)F-FDG for preclinical PET imaging of breast cancer: effect of tamoxifen treatment on tracer uptake by tumor.

INTRODUCTION: AMBA is a bombesin analogue that binds to GRPr. In a mouse model of estrogen-dependent human breast cancer, we tested whether (68)Ga-AMBA can be used for PET detection of GRPr-expressing tumors and could be more accurate than (18)F-FDG to monitor tumor response to hormone therapy. METHODS: The radiolabeling of (68)Ga-AMBA was automated using a R&D Synchrom module. ZR75-1, a breast cancer cell line, was xenografted in nude mice. (68)Ga-AMBA tumor uptake was compared with that of (18)F-FDG before and after treatment with tamoxifen. RESULTS: AMBA was (68)Ga-radiolabelled in 30min with 95.3% yield and purity≥98%. Prior to treatment, (68)Ga-AMBA was highly concentrated into tumors (tumor to non-tumor ratio=2.4 vs. 1.3 with (18)F-FDG). With tamoxifen treatment (n=6) (68)Ga-AMBA uptake plateaued after 1week and decreased after 2weeks, with a significant reduction compared to controls (n=4). In contrast the effect of tamoxifen treatment could not be appreciated using (18)F-FDG. CONCLUSIONS: (68)Ga-AMBA appeared better than (18)F-FDG to visualize and monitor the response to hormone treatment in this breast cancer model.

Current applications of PET imaging of sex hormone receptors with a fluorinated analogue of estradiol or of testosterone.

Currently, the most frequent approach in the oncologic applications of positron emission tomography (PET) is detecting the hypermetabolic activity of the cancer tissue. A more specific approach, which may be complementary, is detecting the overexpression of receptors. In this review article, we aim to evaluate the results that are currently available for PET imaging of the sex hormone receptors in clinical oncology. The indication of PET and now PET/CT has been more disputed in breast carcinoma than in many other primary cancers (e.g., lung, head and neck, colorectal, lymphoma). 18F-fluorodeoxyglucose (FDG), the glucose analogue for PET imaging, has a limited sensitivity to detect the primary breast tumors in case of lobular or in situ forms or small sized tumors localised on systematic mammography, and to identify minimal node invasion in the axilla. Using 16α-[¹8F]fluoro-17ß-estradiol (FES), a fluorinated estradiol analogue, PET is able to detect the over-expression of the oestrogen receptor (ER) in lesions, at a whole-body level. FES and FDG appear complementary for a better diagnostic performance in staging locally advanced breast cancer or restaging recurrent or metastatic breast cancer. Another potential indication is predicting the response to starting or resuming hormone therapy in patients with metastatic breast cancer, in relation with the ER status of all lesions revealed by FES PET. In two retrospective studies, FDG PET was also able to predict the response to hormone therapy, on basis of a metabolic flare, observed either after 7-10 days of treatment or during an estradiol challenge. A prospective comparison of those approaches is warranted. One study reported predicting response to neoadjuvant chemotherapy thanks to a low value of FES SUV(max) or FES/FDG SUV(max) ratio. The presence of ER in uterine tumors, including the benign ones, in ovarian cancers or even in meningiomas, may have therapeutic consequences and FES PET could have a clinical utility in those settings; only initial results are available. The indication of PET and PET/CT has been even more disputed in prostate carcinoma, due to the lack of significant FDG uptake in most cases, at least before the castration-resistant stage. Using FDHT, a fluorinated testosterone analogue, PET is able to detect the over-expression of the androgen receptor (AR) in lesions, at a whole-body level. At least partly due to the rather large number of alternative tracers that are in development or even routinely available in some countries, few FDHT studies have been published until now. From absorbed dose values previously published for FES by the team of University of Washington School of Medicine at Seattle, and for FDHT by the teams of Memorial Sloan-Kettering Cancer Center at New York and of Washington University at St. Louis, we applied the coefficients of ICRP publication 103 and calculated an effective dose per unit of injected activity of 0.023 mSv/MBq for FES and 0.018 mSv/MBq for FDHT. The radiation exposure is of the same order of magnitude as with FDG.

[18F]-FDG positron imaging in clinical management of lymphoma patients.

[18F]-FDG is a glucose analogue labelled with a short-lived positron emitter. During the past decade, it has been proposed to detect in vivo lymphoma lesions with PET, a new non-invasive imaging modality. We aimed at reviewing the current experience with FDG in several clinical settings of lymphoma. Due to the lack of specificity of FDG for lymphoma, histology remains compulsory to establish the diagnosis. Nevertheless, in the case of AIDS, FDG imaging has been proposed to differentiate lymphoma and opportunistic infections in brain lesions. To explore lymphoma extension, FDG-PET highlights more lesions than CT or the clinical examination and results in upstaging 13% of cases. It could also be used for selecting a site for biopsy when the location considered first clinically is difficult to access. Staging lymphoma with FDG-PET also provides baseline images for subsequent evaluation of therapy, which is one of the most promising indications: a negative scan predicts response to therapy and subsequent remission with a predictive value of 89%, and a positive scan either reflects resistance or predicts relapse with a predictive value of 83%. The current achievement of FDG imaging is the early detection of recurrence or of viable tissue in residual masses that remain several months after treatment. Both its sensitivity (84%) and its specificity (95%) overwhelm the values of conventional imaging, mainly CT and gallium-67 scintigraphy. When PET, as a new clinical imaging modality, is not yet widely demanded by clinicians and/or the number of FDG examinations is less than 500 per year, a 'hybrid' gamma-camera or CDET can be an alternative to dedicated PET. For 3 years, we have been using FDG-CDET in the 2D mode without attenuation correction, and obtained the following accuracy in a total of 40 examinations that could be evaluated: 85% for assessment of chemotherapy and 92% to detect recurrences and evaluate residual masses. Our preliminary results also stress the interest in FDG examination in childhood lymphoma, with the same indications as in adults.

CT and (18)F-deoxyglucose (FDG) image fusion for optimization of conformal radiotherapy of lung cancers.

PURPOSE: To validate a computed tomography (CT) and (18)F-deoxyglucose (FDG) image fusion procedure and to evaluate its usefulness to facilitate target definition and treatment planning in three-dimensional conformal radiation therapy (3D-CRT) for non-small-cell lung cancer. METHODS AND MATERIALS: Twelve patients were assessed by CT and FDG-coincidence mode dual-head gamma camera (CDET) before radiotherapy. The patients were placed in a similar position during CT and FDG-CDET. Matching was achieved by minimizing the cost function by 3D translation and rotation between four landmarks drawn on the patient's skin. Virtual simulation was performed from image fusion and estimated dose-volume histograms (DVH) were calculated. RESULTS: Quantitative analysis indicated that the matching error was < 5 mm. Fusion of anatomic and metabolic data corrected staging of lymph nodes (N) for 4 patients and staging of metastases for 1 patient. In these 5 patients, DVH revealed that the lung volume irradiated at 20 Gy (Vl(20)) was decreased by an average of 22.8%, and tumor volume irradiated at the 95% isodose (V(95)) was increased by 22% and 8% for 2 patients, respectively, and was decreased by an average of 59% for 3 patients after fusion. No difference in terms of Vl(20) and V(95) was observed for the other 7 patients. CONCLUSION: We have validated CT and FDG-CDET lung image fusion to facilitate determination of lung cancer volumes, which improved the accuracy of 3D-CRT.

Evaluation of FDG uptake by renal malignancies (primary tumor or metastases) using a coincidence detection gamma camera.

UNLABELLED: The aim of this study was to evaluate the usefulness of FDG scanning using an ordinary gamma camera equipped with coincidence detection (CDET) for 2 renal cancer indications: characterization and staging of renal masses before nephrectomy and search for recurrence after nephrectomy. METHODS: Between September 1997 and June 1998, a whole-body scan and at least 1 tomoscintigram were obtained on 23 occasions in 22 patients (fasting for at least 6 h) using a Prism XP 2000 CDET gamma camera; scanning was begun 45 min after intravenous injection of 150-250 MBq FDG. RESULTS: Postoperative histologic evidence was obtained from 13 of 16 patients who underwent FDG using a CDET gamma camera before renal surgery; 4 renal masses did not accumulate FDG (3 true-negatives, 1 false-negative), whereas 9 renal tumors accumulated FDG (8 true-positives, 1 false-positive). In the other 3 patients, only 1 extrarenal site of FDG uptake was checked and confirmed on histologic examination: a bone metastasis from renal cell carcinoma in 2 cases and lymph node metastasis from a squamous cell carcinoma (3 true-positives). The primary local and regional staging of the malignant renal tumors was accurate in the 9 patients who underwent nephrectomy (8 true-negatives, 1 true-positive). The primary distant staging was positive in 1 case (focus in the chest corresponding to a probable true-positive on follow-up). In the 7 examinations performed because of suspected recurrence of renal cell carcinoma several months after nephrectomy, metastases were visualized by FDG in 4 patients, confirmed by biopsy in 2 patients, and confirmed by conventional imaging or follow-up (or both) in 2 patients. The other 3 patients had negative FDG scans, corresponding to probable true-negative results on follow-up. CONCLUSION: FDG using a CDET gamma camera can be used effectively for the staging and restaging of renal tumors and might be useful for characterization of the primary renal tumor in doubtful cases.

Intra-vascular large B-cell lymphoma revealed by a nephrotic syndrome: a one year remission induced by a high frequency CHOP and rituximab.

Intra-vascular lymphoma is usually reported as a rare and fatal disorder. We describe here the first case of an intra-vascular lymphoma revealed by a nephrotic syndrome for which a durable remission has been obtained by 8 cycles of bi-mensual CHOP and Rituximab therapy. In this report, 18 fluorodesoxyglucose tomoscintigraphy is discussed as a tool for intra-vascular lymphoma extension and follow-up.

Comparison of bone scanning and CA 15-3 serum concentration in the follow-up of breast cancer.

The follow-up bone scans (BS) of 158 women with breast cancer and without known bone metastases were reviewed and compared with serum CA 15-3 concentration. Ninety-three BS were systematic (normal serum CA 15-3) and 3 corresponded to proven bone metastases. Sixty-five BS were motivated:-by isolated bone pain (20 BS. 1 corresponding to metastases),-by bone pain and signs of progression of the disease (11 BS. 7 corresponding to metastases: elevated serum CA 15-3 except in one case), by known visceral metastases (20 BS. 6 corresponding to metastases with elevated serum CA 15-3), by an isolated increase of serum CA 15-3 (7 BS. 4 corresponding to metastasis) by local recurrence (7 BS. 1 corresponding to metastasis). These results show that bone metastases were diagnosed in 6 patients whose serum CA 15-3 concentration was normal. We conclude that the existence of normal tumor markers is not sufficient to exclude the possibility of bone metastases.

Reevaluaton of the usefulness of systematic bone scanning in initial staging and follow-up of small cell lung carcinoma, taking into account the serum levels of neuron-specific enolase.

The prescription of bone scans (BS) in the initial staging and follow-up of small cell lung carcinoma (SCLC) is a traditional attitude. The availability of the serum neuron-specific enolase (NSE) assay and budget limitations led us to evaluate retrospectively, in 57 patients, the consequences of a more selective attitude, namely to perform BS only in those patients with abnormal serum NSE levels. Both BS and NSE assays were performed in 47 patients referred for initial staging of SCLC; NSE levels were normal in 8 but in 2 of these cases (25%) secondary bone localizations with great clinical significance were discovered at BS. During follow-up, 59 BS were performed in conjunction with NSE assays; 45 NSE levels were in the normal range whereas 17 (38%) corresponding BS were suggestive of bone metastases. In conclusion, due to the frequent occurrence of false-negative results in patients with bone metastases, serum NSE levels proved to be useless in the selection for BS of patients suffering from SCLC.

CA 15-3 and bone scintigraphy in the follow-up of breast cancer.

By means of the retrospective study of the clinical records of 158 women followed for breast cancer, we aimed to evaluate the consequences of a non-systematic indication for bone scan (BS) based either on CA 15-3 levels alone or a combination of tumor marker levels and clinical criteria. With the first option, the negative predictive value was 95% and 82% of the BS would have been avoided. With the second option, the negative predictive value was 97% and 59% of the BS would have been avoided. Furthermore, the preliminary results of a longitudinal study showed that those patients with normal CA 15-3 levels and positive bone scans showed a subsequent rise in CA 15-3 levels which frequently became elevated with a average delay of 15 months. Omission of systematic bone scans in the follow-up of breast cancer patients is likely to lead to a delay in the diagnosis of bone metastasis in 3% to 5%, the consequences of which have to be examined carefully.

In vivo inaccessibility of somatostatin receptors to 111In-pentreotide in primary renal cell carcinoma.

The presence of somatostatin receptors on human renal cell carcinomas in surgically removed kidneys has been demonstrated by autoradiography. The aim of this study was to detect to in vivo presence of somatostatin receptors in primary renal tumours and their possible metastases before surgery, using 111In-pentreotide scintigraphy. 201Tl was used as a sensitive tumour-seeking agent with blood flow-dependent uptake. Fifteen patients were imaged before surgical removal of the renal tumour. Thirteen tumours were malignant. The large tumours (more than 4 cm in diameter) did not accumulate 111In-pentreotide or 201Tl. In contrast, the single small tumour accumulated both tracers. A scalp skin metastasis was demonstrated in one patient by 201Tl and 111In-pentreotide uptake. In one case, known lung metastases were visualized with both 201Tl and 111In-pentreotide, but the lung metastases of another three patients as well as one case of epidural metastasis were not identified. In one patient with a photopaenic lesion, positive labelling of the surgically removed tumour was demonstrated by in vitro autoradiography. Somatostatin receptor scintigraphy with 111In-pentreotide appears to have little value for the detection of metastases in patients with renal cell carcinoma, as some metastases (especially those of the lungs) were missed. The absence of 111In-pentreotide uptake by large primary tumours is an interesting finding, suggesting inaccessibility of these very large tumours to drugs.