The aim of this study is to investigate the clinical role of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with carcinoma of unknown primary (CUP). One hundred twenty one patients with a diagnosis of CUP who underwent whole body 18F-FDG PET/CT imaging were included in this retrospective study. The final diagnoses were confirmed either histopathologically or by clinical follow-up. The 18F-FDG-PET/CT successfully detected the primary tumor in 59 out of 121 (49%) patients. The most common primary tumor as detected by 18F-FDG PET/CT was lung cancer (n=31). In a patient, two primary tumors (colon and prostate) were detected on PET/CT imaging. Bone marrow biopsy revealed prostate cancer in this patient and the colon cancer was accepted as a synchronous second primary tumor. 18F-FDG PET/CT findings were false-positive in 11 patients. 18F-FDG PET/CT could not detect any primary lesion in 51 patients, whose conventional work-up detected a primary tumor in 11 and thus considered as false-negative. The sensitivity, specificity rate and accuracy of 18F-FDG PET/CT in detection of primary tumor were identified as 84%, 78% and 82%, respectively. Whole body 18F-FDG PET/CT is an effective method for detecting the primary tumor in patients with CUP. In addition to detecting the primary tumor, it can also help determine disease extent and contribute to patient management.

Laryngeal tuberculosis is a rare presentation of tuberculosis. It can mimic laryngeal carcinoma with its clinical and imaging findings. A 51-year old woman underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging for clinically suspected carcinoma of the larynx. PET/CT revealed lung lesions consistent with tuberculosis in additional to hypermetabolic focus on larynx. The patient was histopathologically diagnosed with lung and laryngeal tuberculosis.

The treatment of stage III non-small cell lung cancer (NSCLC) is complex. Here, we aimed to examine the prognostic utility of sarcopenia and metabolic muscle volumes and evaluate their relationship with oncological treatments in patients with locally advanced NSCLC. Patients with unresectable stage III NSCLC were evaluated retrospectively. Muscle fields were measured, and metabolic parameters of the psoas were obtained. The skeletal muscle index (SMI), sarcopenia, sarcopenic obesity, and body mass index (BMI)-associated sarcopenia were evaluated. Fifty-three (94.6%) patients were men, and three (5.4%) were women. Sarcopenia was identified in 36 (64.3%) patients. Pretreatment sarcopenia and BMI-associated sarcopenia negatively affected overall survival (p = 0.040 and 0.023, respectively). A high psoas SUVmean (Standardized Uptake Value mean) and low mean psoas HU (Hounsfield unit) were poor prognostic factors (p = 0.009 and 0.014, respectively). SMI and muscle mass decreased after oncological treatment. Advanced age, inability to complete treatment, administration of chemoradiotherapy after chemotherapy, presence of sarcopenia, and a low mean psoas HU decreased survival. In conclusion, sarcopenia and BMI-associated sarcopenia are poor prognostic factors in patients with lung cancer. Oncological treatments can adversely affect muscle mass. The metabolic parameters of the psoas muscle can predict patient prognosis.

Purpose: This study aimed to investigate the contribution of metabolic positron emission tomography/computed tomography (PET/CT) parameters of the primary tumor in predicting regional lymph node metastasis (LNM) at initial staging in patients with head and neck squamous cell carcinoma (HNSCC). Methods: A total of 114 patients diagnosed with HNSCC and who underwent PET/CT scanning for staging were included in the study between May 2014 and December 2020. Predictive values of maximum standardized uptake value (SUVmax), maximum standardized uptake ratio (SURmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor in the prediction of cervical LNM were evaluated with logistic regression. Results: The patients were diagnosed with cancer of the larynx (46.5%), oropharynx (9.6%), nasopharynx (22.8%), hypopharynx (4.4%), and oral cavity (16.7%). All metabolic parameters of the primary tumor were significantly different between patients with positive and negative LNM (all P < 0.001). MTV (P = 0.022) and TLG (P = 0.007) were significantly higher in patients with contralateral LNM. MTV value of the primary tumor was found as the single significant predictor of regional LNM in patients with HNSCC (OR = 23.17, P < 0.001 vs. OR = 31.1, P < 0.001, respectively) in univariate and multivariate logistic regression analyses. The sensitivity, specificity, and accuracy of MTV were 89%, 80%, and 86%, respectively. Conclusion: MTV of the primary tumor can predict regional LNM and guide the selection of the treatment modalities and clinical decisions in patients with HNSCC at initial staging.

Objective: To investigate whether age or other factors are determinants of distant metastasis in patients with lung cancer. Study Design: Observational study. Place and Duration of Study: Department of Nuclear Medicine, Recep Tayyip Erdogan University, Rize, Turkey between December, 2018 and February, 2019. Methodology: A total of 152 patients with lung cancer, who underwent positron emission tomography/computed tomography (PET/CT) for staging, were included in this study. Patients were grouped according to age (>65 and <65 years) and distant metastasis status. Metastasis localisation of patients was evaluated by PET/CT. Univariate/multivariate regression analyses were performed to determine risk factors for distant metastasis. Results: No significant difference was found when the relation of distant metastasis with stage distribution was examined both age groups. Distant metastasis rates were significantly higher in female patients than in male patients (p = 0.019) and in patients with small-cell lung carcinoma (SCLC)-adenocarcinoma than in those with other histopathological subtypes (p <0.001). Most of the patients in both groups had a stage 4 disease, and bone distant metastasis was the most common in both age groups. Univariate/multivariate analyses identified that female gender (p = 0.017/p = 0.003), SCLC subtype (p = 0.013/p 0.008), T3/T4 tumour (p <0.001/p 66 pack-years (p = 0.047/p = 0.047) were independent factors for the presence of distant metastasis. Conclusion: Although age is not a risk factor for distant metastasis in lung cancer, female gender, T3/4 tumour, SCLC subtype, and smoking history of >66 pack-years are high-risk factors. PET/CT is recommended as the first-choice imaging technique in patients with lung cancer indicated for distant metastasis scanning.

The study was to evaluate the effect of radioactive iodine (RAI) treatment application time and clinical, histopathological factors on ablation success in patients with operated papillary thyroid cancer (PTC) in low and intermediate-risk. One hundred sixty-one patients with PTC in the low and intermediate-risk were evaluated. Most patients (89.4%) were in the low-risk, and 10.6% were in the intermediate-risk. When the patients were divided into two groups according to the date of receiving RAI treatment after surgery, those who received early treatment (≤3 months) constituted the majority of the patients (72.7%). Seventeen patients received 1.85 Gigabecquerel (GBq), 119 3.7 GBq, 25 5.55 GBq RAI. Most patients (82%) achieved ablation success after the first RAI treatment. The time interval between surgery and RAI treatment did not affect ablation success. Stimulated Tg level measured on the RAI treatment day was an independent predictive factor for successful ablation (p<0.001). The cut-off value of Tg found to predict ablation failure was 5.86 ng/ml. It was concluded that 5.55 GBq RAI treatment could predict ablation success compared to 1.85 GBq dose (p=0.017). It was concluded that having a T1 tumor may predict treatment success compared to a T2 or T3 tumor (p=0.001, p<0.001, retrospectively). The time interval does not affect ablation success in low and intermediate-risk PTC. The ablation success rate may decrease in patients who receive low-dose RAI and have high Tg levels before treatment. The most crucial factor in achieving ablation success is giving enough doses of RAI to ablate the residual tissue.