Assessment of response to endocrine therapy using FDG PET/CT in metastatic breast cancer: a pilot study.

PURPOSE: The purpose of this pilot study was to assess whether outcome in metastatic or recurrent breast cancer patients is related to metabolic response to endocrine therapy determined by (18)F-FDG PET/CT. METHODS: The study group comprised 22 patients with breast cancer (age 58 ± 11 years, mean ± SD) who were scheduled to receive endocrine therapy. They were systematically assessed by PET/CT at baseline and after a mean of 10 ± 4 weeks for evaluation of response after induction. All patients demonstrated FDG-avid lesions on the baseline PET/CT scan. The metabolic response was assessed according to EORTC criteria and based on the mean difference in SUV(max) between the two PET/CT scans, and the patients were classified into four groups: complete or partial metabolic response, or stable or progressive metabolic disease (CMR, PMR, SMD and PMD, respectively). All patients were followed in our institution. RESULTS: Metastatic sites were localized in bone (n = 15), lymph nodes (n = 11), chest wall (n = 3), breast (n = 5), lung (n = 3), soft tissue (n = 1) and liver (n = 1). PMR was observed in 11 patients (50%), SMD in 5 (23%) and PMD in 6 (27%). The median progression-free survival (PFS) times were 20, 27 and 6 months in the PMR, SMD and PMD groups, respectively. PFS in the SMD group differed from that in the PMR and SMD groups (p < 0.0001). CONCLUSION: Metabolic response assessed by FDG PET/CT imaging in patients with metastatic breast cancer treated with endocrine therapy is predictive of the patients' PFS.

Single photon emission tomography/computed tomography (SPET/CT) and positron emission tomography/computed tomography (PET/CT) to image cancer.

Hybrid systems associating the sharpness of anatomic images coming from computed tomography (CT) and radionuclide functional imaging (SPET or PET) are opening a new era in oncology. This multimodal imaging method is now routinely used for the diagnosis, extent, follow up, treatment response and detection of occult disease in different types of malignancies with a significant impact on the treatment strategy leading for a change for more than 68% of all investigated patients.

Diagnostic and therapeutic imaging for cancer: therapeutic considerations and future directions.

As cancer treatment cost soar and the mantra for "personalized medicine" grows louder, we will increasingly be searching for solutions to these diametrically opposed forces. In this review we highlight several exciting novel imaging strategies including MRI, CT, PET SPECT, sentinel node, and ultrasound imaging that hold great promise for improving outcomes through detection of lymph node involvement. We provide clinical data that demonstrate how these evolving strategies have the potential to transform treatment paradigms.

High and typical 18F-FDG bowel uptake in patients treated with metformin.

PURPOSE: This prospective and bi-centric study was conducted in order to determine the impact of antidiabetic treatments (AD) on (18)F-FDG bowel uptake in type 2 diabetic patients. METHODS: Fifty-five patients with previously diagnosed and treated type 2 diabetes mellitus (group 1) were divided in two subgroups: AD treatment including metformin (n=32; group 1a) and AD treatment excluding metformin (n=23; group 1b). The 95 patients without diabetes mellitus made up controls (group 2). (18)F-FDG uptake in small intestine and colon was visually graded and semi-quantitatively measured using the maximum standardized uptake value. RESULTS: (18)F-FDG bowel uptake was significantly increased in AD patients (group 1) as compared to controls (group 2) (p<0.001). Bowel uptake was significantly higher in AD patients including metformin (group 1a) as compared to AD patients excluding metformin (group 1b) (p<0.01), whose bowel uptake was not significantly different from controls (group 2). A metformin treatment was predictive of an increased bowel uptake in the small intestine (odds ratio OR=16.9, p<0.0001) and in the colon (OR=95.3, p<0.0001), independently of the other factors considered in the multivariate analysis. Bowel uptake pattern in the patients treated with metformin was typically intense, diffuse and continuous along the bowel, strongly predominant in the colon, in both the digestive wall and lumen. CONCLUSION: This study emphasizes that metformin significantly increases (18)F-FDG uptake in colon and, to a lesser extent, in small intestine. It raises the question of stopping metformin treatment before an (18)F-FDG PET/CT scan is performed for intra-abdominal neoplasic lesion assessment.

Impact of FDG PET-CT imaging on the decision making in the biologic suspicion of ovarian carcinoma recurrence.

OBJECTIVES: The aim of this prospective study was to evaluate the impact of integrated PET-CT on treatment management in ovarian carcinoma recurrence suspicion because of increased CA-125. METHODS: Twenty-nine patients (mean age=61 years), initially treated for ovarian carcinoma (FIGO stage I n=2, stage II n=3, stage III n=21 and stage IV n=3), presenting with increased CA-125 (mean=160 IU/ml, range 33-1930), underwent subsequently a CT and a PET-CT scans. The recurrence was acknowledged by the referring physicians for all patients. The impact of PET-CT on patient's management was evaluated by comparing the therapeutic decision mentioned respectively on the pre and post PET-CT questionnaires filled in by the oncologists. RESULTS: The CT scan was positive in 22/29 patients (76%) and negative in 7/29 patients (24%). The PET-CT scan was positive in 27/29 patients (93%) and negative in 2/29 (7%) patients. Five out of the seven patients with a negative CT scan had a positive PET-CT scan. In comparison to CT scan alone, the PET-CT scan modified the disease distribution for 16 patients (55%; p<0.001) in the following ways: more advanced disease (n=11), more limited disease (n=4), and different localizations (n=1). The assessment of pre and post PET-CT questionnaires showed a statistically significant change in the decision making for 10 patients (34%, p<0.0001). CONCLUSION: This questionnaire-based study showed that PET-CT imaging allows a better restaging than CT and induces a change in clinical management in over one third of patients with suspected ovarian carcinoma recurrence on increased CA-125.

Diagnosis and localization of renal cyst infection by 18F-fluorodeoxyglucose PET/CT in polycystic kidney disease.

Renal cyst infection in polycystic kidney disease is a serious complication. Early diagnosis and localization of infected cyst are crucial and usually require conventional imaging modalities, including ultrasound and computed tomography (CT). However, their contribution is limited because of nonspecific results. We report on a patient with suspected renal cyst infection for which 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT scan allowed the exact localization of the infected cyst and guided a drainage procedure. FDG-PET/CT imaging could be a valuable tool for early identification of infected renal cyst infection, and may contribute to better patient management.

In search of an unknown primary tumour presenting with cervical metastases: performance of hybrid FDG-PET-CT.

OBJECTIVES: In patients with cervical lymph node metastases from unknown primary tumour (UPT), the primary tumour is frequently localized in the head and neck area. Because the detection of the primary tumour is of importance to optimize the patient's management and allows a targeted therapy, the performances of hybrid positron emission tomography-computed tomography (PET-CT) using fluorodeoxyglucose (FDG) were evaluated in a retrospective study. METHODS: Thirty-eight consecutive patients with cervical lymph node metastases, and in whom the primary was not detected by the comprehensive diagnostic work-up including endoscopy and conventional imaging methods, were referred for a PET-CT scan. RESULTS: PET-CT was positive with an increased FDG focal uptake suggesting the potential primary site in 68% of patients (26/38), which guided the biopsies during a second rigid panendoscopy in 17 of these 26 patients: 13 primary tumours were then histologically proven. PET-CT showed distant lesions in three patients. It had treatment-related implications in 23/38 patients (60%), consisting of modification of radiation planning, surgery or abstention from surgery. CONCLUSION: Hybrid FDG-PET-CT is helpful for the detection of a potential head and neck primary tumour. Furthermore, hybrid FDG-PET-CT has the ability to diagnose occult or distant second tumour and metastatic disease and modify patient management.

[The role of PET scan in gastrointestinal stromal tumors]. / Place de l'imagerie par Tomographie par Emission de Positons pour les tumeurs stromales gastro-intestinales.

Abdominal CT is considered the imaging method of choice for the staging and treatment monitoring of Gastrointestinal Stromal Tumors (GIST). The role of Whole-body FDG-PET seems limited for staging because of the low rate of extra-abdominal tumoral involvement and lower sensitivity than CT. However, PET provides assessment of therapeutic response to imatinib as early as 8 days after treatment is begun. The decrease in the metabolic tumor activity is often marked and intense and it is easier to evaluate than changes in tumor shrinkage and density measured on CT. PET may also be useful when morphological findings are unclear, treatment efficacy uncertain or when progression is identified on CT scan, especially when these findings do not agree with clinical data. PET and CT are complementary and hybrid PET/CT systems have been shown to be useful in GIST. PET may be proposed for the assessment of treatment response in prospective studies with imatinib or other molecules. In patients with GIST, FDG-PET should be performed based on a pluridisciplinary decision.

[FDG (18 fluorodeoxyglucose) positron emission tomography and breast cancer]. / Tomographie par emission de positons (TEP) au FDG et cancer du sein.

Positron emission tomography (PET) is a metabolic radionuclide imaging method in which a tracer labeled with a positron emitter is detected with a dedicated system. 18F-fluorodeoxyglucose (FDG) accumulates in tumor cells because of their increased glycolytic activity, and is thus widely used as a tracer in oncology. This increased metabolic activity precedes morphologic modifications, making FDG-PET a very useful tool for detecting and staging cancer. It can also be used to characterize morphologic changes, differentiating not only between benign and malignant lesions, but also between viable tumor cells and areas of necrosis and/or fibrosis induced by treatments. Being a whole-body examination, it allows malignancies to be staged in a single procedure. Systems combining PET and CT (computed tomography) offer improved performance, providing both metabolic and anatomical data. This technique appears to be useful for initial breast cancer staging, especially of locally advanced forms and suspected recurrences (increase of isolated tumor marker). Early studies of PET evaluation of responses to hormonal and/or cytotoxic therapies have also given very promising results. However, this technique does not seem sufficiently sensitive to be included in the initial screening or diagnosis of primary tumors, owing to its limited resolution (about 5 mm) and its restricted availability. This approach is poorly sensitive when used for axillary assessment, but offers good specificity.

Incidental colonic focal lesions detected by FDG PET/CT.

OBJECTIVE: The aim of this study was to assess the performance of FDG PET/CT for the detection of colonic lesions, especially advanced neoplasms (villous or >10-mm adenomas, carcinomas). Because of 18F FDG accumulation in adenomatous polyps, PET using FDG can detect early premalignant colorectal lesions. MATERIALS AND METHODS: FDG PET/CT studies performed for a 1-year period in 1,716 consecutive patients with various malignant diseases, except colorectal cancer, were retrospectively reviewed. PET images obtained 1 hr after FDG injection and non-contrast CT images used for attenuation correction were fused for analysis. Of 45 patients showing intense focal colonic FDG uptake, 20 patients (with 21 foci) underwent a colonoscopic investigation, and, when necessary, polyp resection. The intensity of FDG uptake was quantified using the standardized uptake value (SUV(max)). RESULTS: The FDG colonic foci were associated with 18 colonoscopic abnormalities in 15 patients, with no colonic abnormality detected in five patients (false-positive [FP] results). Histopathologic findings revealed advanced neoplasms in 13 patients (13 villous adenomas and three carcinomas) and two cases of hyperplastic polyps. A difference in the mean SUV(max) was found between FP and true-positive colonic FDG foci but was not statistically significant (p = 0.14). CONCLUSION: Presence of a focal colonic FDG uptake incidental finding on a PET/CT scan justifies a colonoscopy to detect (pre-)malignant lesions. The fusion of PET and CT images allows an accurate localization of the lesions. PET/CT is a useful tool to differentiate pathologic from physiologic FDG uptake.