RESUMO
Background Imaging with F18-fluorodeoxyglucose PET/CT is used to determine sites of abnormal glucose metabolism and can be used to characterize and localize many types of tumors. Aim To assess the prevalence of multiple primary malignant neoplasms (MPMN) detected by PET/CT in cancer patients. Material and Methods F18-fluorodeoxyglucose PET/CT scans performed to 800 patients with a newly diagnosed cancer or with already treated tumors were retrospectively reviewed. In patients whose examination described incidental findings not related to the primary tumor, a research was done about further laboratory, imaging or pathological studies. Results In 188 PET/CT scans (23%) an incidental finding was found. Of these, 66 (35%) were considered as MPMN, 12 as atypical metastases of a known primary tumor, 14 as false positive images (inflammatory or physiologic uptake) and 29 as benign or low grade tumors. In 67 cases (36% of all incidental tumors), the finding was not confirmed. Seven percent of patients with a newly diagnosed tumor had a synchronic MPMN detected by PET/CT. Nine percent of patients with treated tumors developed a metachronous MPMN during their follow up. The most common incidental tumors were thyroid cancer in 15 cases, kidney cancer in 13, lung cancer in 10, colorectal carcinoma in 9, breast cancer in 6, prostate cancer in 4, non-Hodgkin lymphoma in 3 and pancreatic cancer in 2. Conclusions A MPMN is detected by PET/CT in a significant number of cancer patients.
Assuntos
Humanos , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Carcinoma/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias Primárias Múltiplas/diagnóstico por imagem , Carcinoma/classificação , Carcinoma/complicações , Adenocarcinoma/classificação , Adenocarcinoma/complicações , Adenocarcinoma/diagnóstico por imagem , Estudos Transversais , Compostos Radiofarmacêuticos , Fluordesoxiglucose F18 , Detecção Precoce de Câncer/métodos , Neoplasias Primárias Múltiplas/classificação , Neoplasias Primárias Múltiplas/complicaçõesRESUMO
Background: PET/CT (Positron emission tomography/computed tomography) is a hybrid image modality widely used in oncology, for staging, therapy evaluation or follow up. Aim: To evaluate the prognostic value ofPET/CT in lung cancer. Material and Methods: Retrospective review of PET/CT records, selecting 51 patients with a lung malignancy, mass or nodule referred for PET/CT between December 2008 and December 2010. All had pathological confirmation of malignancy and had not been treated previously. Age, gender, body mass index, radiological features of lung tumor and metastases, and lung tumor 18F-fluoro-2-deoxy-d-glucose uptake using the SUV (Standardized uptake value) index were recorded. Survival was analyzed usingKaplan-Meier curves and a Cox proportional regression analysis. Results: Pathology confirmed the presence of lung cancer in 47 patients aged 30 to 88 years. Four patients (7.8%) had other type of tumors such as carcinoid or lymphoma. Fifty percent of lung cancer patients died during a mean observation lapse of 18 months (range: 2-34 months). Patients with metastases, local lymph node involvement, a lung tumor size > 3 cm and high tumor uptake (SUVmax > 6) had significantly lower survival. Occurrence of metastases was the only independent prognostic factor in the Cox regression. A lung lesion with a SUVmax ≥ 12 was always associated to hilar/mediastinal lymph node involvement. Conclusions: PET/CT imaging gives important prognostic information in lung cancer patients.