Contribution of F-18 fluorodeoxyglucose PET/CT and contrast-enhanced thoracic CT texture analyses to the differentiation of benign and malignant mediastinal lymph nodes.

BACKGROUND: Texture analysis and machine learning methods are useful in distinguishing between benign and malignant tissues. PURPOSE: To discriminate benign from malignant or metastatic mediastinal lymph nodes using F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and contrast-enhanced computed tomography (CT) texture analyses with machine learning and determine lung cancer subtypes based on the analysis of lymph nodes. MATERIAL AND METHODS: Suitable texture features were entered into the algorithms. Features that statistically significantly differed between the lymph nodes with small cell lung cancer (SCLC), adenocarcinoma (ADC), and squamous cell carcinoma (SCC) were determined. RESULTS: The most successful algorithms were decision tree with the sensitivity, specificity, and area under the curve (AUC) values of 89%, 50%, and 0.692, respectively, and naive Bayes (NB) with the sensitivity, specificity, and AUC values of 50%, 81%, and 0.756, respectively, for PET/CT, and NB with the sensitivity, specificity, and AUC values of 10%, 96%, and 0.515, respectively, and logistic regression with the sensitivity, specificity, and AUC values of 21%, 83%, and 0.631, respectively, for CT. In total, 13 features were able to differentiate SCLC and ADC, two features SCLC and SCC, and 33 features ADC and SCC lymph node metastases in PET/CT. One feature differed between SCLC and ADC metastases in CT. CONCLUSION: Texture analysis is beneficial to discriminate between benign and malignant lymph nodes and differentiate lung cancer subtypes based on the analysis of lymph nodes.

The role of metabolic tumor parameters predicting cervical lymph node metastasis in patients with head and neck squamous cell carcinoma.

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.

Relation of whole-body metabolic tumor volume and total lesion glycolysis on fluorodeoxyglucose PET/computed tomography with clinical and laboratory parameters in newly diagnosed multiple myeloma.

OBJECTIVE: This study aims to evaluate the relationships of metabolic fluorodeoxyglucose PET/computed tomography (FDG PET/CT) parameters such as whole-body metabolic tumor volume (WB MTV), WB-total lesion glycolysis (TLG), and bone marrow (BM)-mean standard uptake value (SUVmean) with clinical stage and other prognostic biomarkers in newly diagnosed multiple myeloma (MM) patients. METHODS: Patients who underwent pretreatment PET/CT with the diagnosis of MM were evaluated retrospectively. The number of focal lesions, WB MTV, WB TLG, and BM SUVmean values were measured on FDG PET/CT images. Clinical stages and prognostic laboratory parameters were recorded the pretreatment period. RESULTS: WB MTV and WB TLG values were significantly higher in patients with more than three focal lesions on FDG PET/CT scan (all P < 0.001). According to the Revised International Staging System (R-ISS), all WB MTV, WB TLG, and BM SUVmean values are significantly higher in patients with stage 3 disease than in stages 1-2 ( P = 0.027, P = 0.019, P = 0.001, respectively). Serum creatinine level is positively correlated with WB MTV, WB TLG, and BM SUVmean values ( P = 0.020, P = 0.004, P < 0.001, respectively). In addition, the ß2 microglobulin level, an essential biochemical prognostic parameter, was positively correlated with the BM SUVmean value ( P = 0.013). CONCLUSION: The BM SUVmean, WB MTV, and WB TLG values, which reflect FDG avid WB tumor burden, are associated with prognostic biomarkers and R-ISS stage in newly diagnosed MM patients. It contributes to the identification of high-risk patients at the pretreatment staging.

Relationships Between DCE-MRI, DWI, and 18F-FDG PET/CT Parameters with Tumor Grade and Stage in Patients with Head and Neck Squamous Cell Carcinoma

Objectives: Properties of head and neck squamous cell carcinoma (HNSCC) such as cellularity, vascularity, and glucose metabolism interact with each other. This study aimed to investigate the associations between diffusion-weighted imaging (DWI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and positron emission tomography/computed tomography (PET/CT) in patients with HNSCC. Methods: Fourteen patients who were diagnosed with HNSCC were investigated using DCE-MRI, DCE, and 18fluoride-fluorodeoxyglucose PET/CT and evaluated retrospectively. Ktrans, Kep, Ve, and initial area under the curve (iAUC) parameters from DCE-MRI, ADCmax, ADCmean, and ADCmin parameters from DWI, and maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) parameters from PET were obtained. Spearman's correlation coefficient was used to analyze associations between these parameters. In addition, these parameters were grouped according to tumor grade and T and N stages, and the difference between the groups was evaluated using the Mann-Whitney U test. Results: Correlations at varying degrees were observed in the parameters investigated. ADCmean moderately correlated with Ve (p=0.035; r=0.566). Ktrans inversely correlated with SUVmax (p=0.017; r=-0.626). iAUC inversely correlated with SUVmax, SUVmean, TLG, and MTV (p<0.05, r≤-0.700). MTV (40% threshold) was significantly higher in T4 tumors than in T1-3 tumors (p=0.020). No significant difference was found in the grouping made according to tumor grade and N stage in terms of these parameters. Conclusion: Tumor cellularity, vascular permeability, and glucose metabolism had significant correlations at different degrees. Furthermore, MTV may be useful in predicting T4 tumors.

Applying postoperative radioiodine therapy before 3 months seems to decrease ablation success in patients with differentiated thyroid carcinoma.

OBJECTIVES: Radioiodine can be applied for remnant ablation in low and low to intermediate-risk patients with differentiated thyroid cancer (DTC). A controversy still exists about the application time interval of radioiodine following total thyroidectomy. In this study, we investigated the effect of radioiodine (RAI) therapy timing on the success rates of the ablation. METHODS: We retrospectively reviewed the data of DTC patients who underwent total thyroidectomy and were treated with radioiodine remnant ablation during 2013-2017. Because the objective of this study was to determine the success of ablation according to the postoperative RAI therapy timing, any patients with a pathologic uptake outside the thyroid bed as well as high-risk patients determined before and at RAI therapy were excluded from the study. Finally, 503 patients with low and low to intermediate-risk groups were included in the study. Successful ablation was defined as no visible focal uptake on the neck on I-131 whole body scan with stimulated thyroglobulin (Tg) level of < 1 ng/mL and a normal or undetectable antithyroglobulin antibody (ATG). The time interval from total thyroidectomy to RAI therapy (titRAI) was calculated as months for each patient. RESULTS: A total of 115 (22.9%) patients were in the low to intermediate-risk group whereas most of the patients were at the low-risk group according to the American Thyroid Association (ATA) 2015. Successful ablation was observed in 388 (77.1%) patients. The titRAI was ≤ 3 months in 151 (30.0%) patients and > 3 months in 352 (70.0%) patients. The ratio of successful ablation was statistically higher in patients with a titRAI > 3 months (81.2% of patients) than in patients with ≤ 3 months (67.5% of patients) (χ2 11.247, p 0.001). The rate of successful ablation was 20.3% higher in patients treated after 3 months. There was no statistical difference when titRAI cut off was reduced to 2 months (p > 0.5). CONCLUSION: Investigated the effect of radioiodine therapy initiated before 3 months after total thyroidectomy and it seems to decrease ablation success.

Factors affecting overall survival and progression-free survival in patients with metastatic castration resistant prostate cancer received 177Lu PSMA I&T therapy.

OBJECTIVE: Lutetium-177 (177Lu) prostate specific membrane antigen (PSMA) radionuclide therapy (RNT) is an effective and safe treatment option in patients with metastatic castration resistant prostate cancer (mCRPC). The first aim of this study was to determine RNT response rate. The second and main aim of this study is measure overall and progression-free survival (OS and PFS) and to determine the factors have effect on OS and PFS. MATERIAL AND METHODS: Patients with mCRPC had 177Lu PSMA RNT every 6-8 weeks. Therapy response of each cycle determined wit PSA after 6-8 weeks. Overall survival and PFS were measured, then effects of age, Gleason grade, local recurrence, extraabdominopelvic located lymph node metastasis, visceral metastasis, prostate specific antigen (PSA) changing after the first RNT, pretreatment PSA, hemoglobin (Hb), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) values on survivals were determined. RESULTS: Forty-five patients were treated with total of 164 cycles of RNT. Fifteen patients (33%) had PSA decline of ≥50%, 23 patients (51%) showed any PSA decline and 20 patients (44%) showed PSA increase of ≥25%. Median OS and PFS were 17,1 months and 7,4 months. Patients had any or ≥50% PSA response after the first cycle, lower initial ALP (<120U/L) had longer OS and PFS. Patients had normal Hb showed longer OS and patients had lower initial PSA (<51ng/mL) had longer PFS. Patients had PSA progression of ≥25% had shorter OS and PFS. CONCLUSION: Prostate specific antigen response after the first cycle, lower initial ALP is related to longer OS and PFS. Normal pretreatment Hb is a predictor of longer OS and lower initial PSA is related to longer PFS. Prostate specific antigen progression after the first cycle causes shorter OS and PFS.