Impact of FDG PET/CT on detection of synchronous and metachronous malignancies and clinical management in patients with multiple primary cancers.

Multiple primary cancers are usually defined as primary malignant tumors of different histological origins in one person. Recently, there has been an increase in the number of patients diagnosed with multiple primary cancers. The study aims to evaluate the role of PET/CT in detecting second primary and subsequent tumors as well as to demonstrate the influence on the treatment management in patients with histologically proven synchronous or metachronous tumors. Fifty patients with clinically proven at least one malignancy have been evaluated and followed up for a year. Another inclusion criterion was a biopsy-proven additional primary synchronous (within 2-6 months after the first one) or metachronous (more than 6 months after the diagnosis of the first one) malignant tumor in a different organ. All patients were scanned on GE Discovery PET/CT 16 slices scanner from the top of the head to mid-thigh. The study was performed one hour after injection, using the weight-adjusted activity, hydration of patients with diuretic stimulation, and oral/i.v. contrast intake. Thirty out of 50 patients were females. The youngest patient was 25 years old, while the highest age was 84 years. Ten of the patients had third primary tumors and one patient had four different malignancies. Metachronous tumors were 2.4-fold higher than synchronous ones. The minimum time to detect a second tumor was 1 month, while the maximum was 15 years. As second malignancies we detected fourteen gastrointestinal cancers (28%), ten urogenital ones (20%), ten pulmonary tumors (20%), five breast cancers (10%), four lymphoma patients (8%), four head and neck squamous cell carcinomas (8%), two NET (4%), and one sarcoma (2%). As a result of the 18F-FDG PET/CT scan, the therapy plans of all 50 patients required modification at the minimum for the second tumor. 64% of the patients had multimodality therapy for their first cancer, which suggests that this approach could play an important role in the development of MPM. 81% of the additional malignancies in the female group, detected by PET/CT were in stages I or II, which provides a higher probability of cure. On the other hand, we detected advanced stage second primary disease in 70% of the patients in the male group. PET/CT can identify a significant number of additional primary neoplasms in patients with known primary cancer, acquiring combined metabolic and morphologic information, as well as its whole-body protocol. Integrated PET/CT can significantly modify the assessment of the tumor's dissemination and often change patient management substantially. Subsequent primary lesions identified after PET/CT scan are mainly in the early stage and thus have an excellent likelihood of being cured if treated promptly and aggressively.

The impact of 18F-FDG PET/CT in the clinical management of patients with lymph node metastasis of unknown primary origin.

The aim of this study was to evaluate the diagnostic performance and the utility of F-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) in the clinical management of patients presenting with lymph node metastasis of undefined primary origin (CUP). A total of 53 patients (34 males, 19 females) with a diagnosis of lymph node metastasis according to the histopathology and/or conventional imaging were enrolled in this retrospective study. Patients were divided into four groups according to the initial location of their metastasis - group 1, cervical lymph nodes (n=39), group 2, axillary lymph nodes (n=6), group 3, mediastinal lymph nodes (n=2) and group 4, abdominal and pelvic lymph nodes (n=6). The site of a probable primary malignancy suggested by PET/CT was confirmed by biopsy/further investigations or follow-up. 18F-FDG PET/CT accurately detected the primary carcinoma in 19 of 53 patients (36%), with head and neck cancer and lung carcinoma being the most common primary locations. The PET-CT scan results were negative for primary site localization in 13% of patients (false-negative), while 45% had true negative results, and 6% displayed false-positive results. Additional distant metastatic foci were identified in 21 of all patients (40%). The overall sensitivity, specificity, and accuracy rates of the study were identified as 73%, 89%, and 81%, respectively; in the group with cervical lymph node metastasis sensitivity 70% and specificity 84%. To conclude, 18F-FDG PET/CT is a sensitive and selective procedure for detecting unknown primary tumors, especially in the clinical setting of cervical lymph node metastasis and its use should be encouraged earlier in the pre-treatment phase of CUP-patients, leading to higher detection of probable primary sites, guiding subsequent biopsy, and more accurate detection of distant metastases in a single examination.

Detection of Ureteral Stump Transitional Cell Carcinoma, Presenting as Bone Metastases from Unknown Primary by 18F-FDG PET/CT: A Case Report with Review of Literature.

A case of occult carcinoma of the ureteral stump is reported. A 67-year-old man presented with pain syndrome due to multiple bone metastases from unknown primary origin detected by previous imaging studies as magnetic resonance imaging, whole body contrast-enhanced computed tomography (CT), and technetium-99m methyldiphosphonate bone scan. He had undergone a right nephrectomy for a benign disease previously. He was referred to our department for an 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) to help localize possible primary tumor. Our observations in this case show that the use of 18F-FDG PET/CT successfully and more accurately evaluated the overall tumor burden and led to a rapid decision of an adequate therapeutic approach.

Interactions of poly(vinylpyrrolidone) with ibuprofen and naproxen: experimental and modeling studies.

PURPOSE: To elucidate the differences in the interaction of chiralic ibuprofen (IBP) and naproxen (NAP) with poly(vinylpyrrolidone) (PVP) in a solid state. METHODS: Drugs/PVP physical mixtures and solid dispersions were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrometry (FT-IR), solid state (13)C NMR spectroscopy, and x-ray diffractometry. Molecular modeling study of the crystal structures and PVP was performed. RESULTS: A spontaneous conversion of IBP/PVP physical mixtures in a stable glasslike form (solid dispersion) was observed after storage. The enantiomer reacted more strongly than the racemate. NAP did not interact with PVP. The crystal structures of drugs showed differences in the hydrogen bonding, aromatic interactions, molecular energies, and distances inside the crystals. The trimer structure of PVP was built and optimized. It was proposed that each PVP monomer could interact with one IBP dimmer in contrast to NAP, where two out of three PVP monomers faced the catemer carboxylic groups. CONCLUSIONS: The differences in the interaction of PVP with racemic IBP, enantiomer IBP, and NAP can be related to the differences in their crystal structures. The correlation between the experimental data and the results of the molecular modeling analysis suggest that the IBP dimmer structures are likely to perform HB and aromatic interactions with PVP.