The relation between staging fluorine-18 fluorodeoxyglucose positron emission tomog- raphy/computed tomography metabolic parameters and tumor necrosis rate in pediatric osteosarcoma patients

Background/aim: The aim of this study was to investigate the contribution of fluorine-18 (F-18) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging in staging of pediatric osteosarcoma patients and also to evaluate the ability of metabolic parameters from the primary tumor to predict tumor necrosis rate (TNR). Material and methods: F-18 FDG-PET/CT imaging was performed in staging 37 pediatric osteosarcoma patients. The metabolic pa- rameters SUVmax (maximum standardised uptake value), MTV (metabolic tumour volume), and TLG (total lesion glycolysis) were measured from the primary tumor. TNR level of the primary tumor was histopathologically measured after standard neoadjuvant chemotherapy treatment. The contribution of F-18 FDG-PET/CT to staging of pediatric osteosarcoma patients and the accuracy of metabolic parameters of the primary tumor to predict TNR were analized by regression analysis. Results: MTV and TLG of the primary tumor were found to efficiently predict histopathologic TNR, whereas SUVmax was not (P = 0.012, P = 0.027, P = 0.25, respectively). Also 5 of 12 patients (41.6%) who were initially defined as localised osteosarcoma were upstaged in consequence of staging F-18 FDG-PET/CT findings. Conclusion: F-18 FDG-PET/CT staging in pediatric osteosarcoma patients can effectively distinguish metastatic-localised disease. MTV and TLG values are important parameters, which can efficiently be used to predict TNR.

Paratesticular Rhabdomyosarcoma Associated with Tuberculosis.

We report a 16-year-old male patient diagnosed with paratesticular rhabdomyosarcoma and mediastinal tuberculous lymphadenitis. The differential diagnosis between high or early stage of rhabdomyosarcoma and tuberculosis (TB) was critical in this patient without a history of TB. Unexpected lymphadenopathies detected during the staging of patients with malignancy should be carefully evaluated, and TB should be taken into consideration in the differential diagnosis especially in underdeveloped and developing countries. Unnecessary additional treatments increase the rate of mortality and morbidity because of upstaging of cancer. Further, TB reactivation can be seen during chemotherapy because of immunosuppression.

The Added-value of Staging 18F-FDG PET/CT in the Prediction of Overall Survival in the Patients with Bladder Cancer.

Objectives: This retrospective study aimed to evaluate the prognostic importance of 18F-fluorodeoxyglucose (18F-FDG)-positive pelvic lymph nodes (LNs) and extra-pelvic disease on staging 18F-FDG positron emission tomography/computed tomography (PET/CT) in patients with bladder cancer. Methods: Bladder cancer patients who underwent staging 18F-FDG PET/CT were included in the study. Histopathologic features of tumors, therapy histories, presence of distinguishable tumors on CT and PET images, sizes and maximum standardized uptake value (SUVmax) of primary tumors, total numbers, sizes, and SUVmax of 18F-FDG-positive pelvic and extra-pelvic LNs, and total numbers and SUVmax of distant metastases (M1a/1b) were recorded. Patients were followed up until death or the last medical visit. Factors predicting overall survival were determined using Cox regression analysis. Results: Fifty-five patients [median age: 70 (53-84), 48 (87.3%) male, 7 (12.7%) female] with bladder cancer were included in this study. Twenty-nine (52.7%) patients had 18F-FDG positive pelvic LNs, while 24 (43.7%) patients had 18F-FDG positive extra-pelvic disease. Patients with 18F-FDGpositive pelvic LNs had a higher rate of extra-pelvic disease (p=0.003). The median follow-up duration was 13.5 months. The median overall survival was 16.3 months [95% confidence interval (CI) 8.9-23.7]. The primary tumor distinguishability on PET (p=0.011) and CT (p=0.009) images, the presence of 18F-FDG-positive pelvic LNs (p<0.001) and 18F-FDG-positive extra-pelvic disease/distant metastases (M1a/M1b) (p<0.001), and the number of distant metastases (p=0.034) were associated with mortality. The 18F-FDG-positive extra-pelvic disease/distant metastases [p=0.029, odds ratio: 4.15 (95% CI 1.16-14.86)] was found to be an independent predictor of mortality in patients with bladder cancer. Conclusion: The presence of 18F-FDG-positive extra-pelvic disease in pretreatment 18F-FDG PET/CT is an important prognostic factor in bladder cancer patients.

Primary tumor heterogeneity on pretreatment 18F-FDG PET/CT to predict outcome in patients with rectal cancer who underwent surgery after neoadjuvant therapy.

PURPOSE: This retrospective study aimed to investigate the value of texture features of primary tumors in pretreatment 18F-FDG PET/CT in the prediction of response to treatment, progression, and overall survival in patients with rectal cancer who underwent surgery after neoadjuvant therapy(NAT). METHODS: Patients with rectal cancer who had pretreatment 18F-FDG PET/CT, and underwent surgery after NAT were included in this study. Clinicopathologic features, date of last follow-up, progression, and death were recorded. Textural and conventional PET parameters(maximum standardized uptake value-SUVmax, metabolic tumor volume-MTV, total lesion glycolysis-TLG) were obtained from PET/CT images using LifeX program. Parameters were grouped using Youden index in ROC analysis. Factors predicting the pathological response to treatment, progression, and overall survival were determined using logistic regression and Cox regression analyses. RESULTS: Forty-four patients (26(59%) male, 18(41%) female; 60.1±11.4 years) with rectal cancer were included in this study. The numbers of patients with responders and non-responders to NAT were 15(34.9%) and 28(65.1%), respectively. One patient' pathology report did not contain the response status to NAT. The median of follow-up duration was 29.9 months. 9(20.5%) showed disease progression, and 8(18.2%) died during the follow-up period. Difference entropyGLCM and correlationGLCM parameters were found as independent predictors for response to NAT. The positivity of surgical margin, intensity interquartile rangeCONV and AUC-CSHDISC texture parameters were independent predictors of progression, while normalized inverse differenceGLCM and LZLGEGLZLM parameters were independent predictors of mortality. CONCLUSION: The texture parameters obtained from pretreatment 18F-FDG PET/CT have presented a more robust predictive value than conventional parameters in patients with rectal cancer who underwent surgery after NAT.

Prognostic value of primary tumor and lymph node volumetric metabolic parameters at pre-treatment F-18 FDG PET/CT in nasopharyngeal carcinoma.

BACKGROUND: The aim of this study was to evaluate the prognostic significance of volumetric metabolic parameters of pre-treatment PET/CT along with clinical characteristics in patients with non-metastatic nasopharyngeal carcinoma. MATERIAL AND METHODS: Seventy-nine patients with nasopharyngeal carcinoma underwent F18- FDG PET/CT for pretreatment evaluation and included in this study. The patient features (patient age, tumor histopathology, T and N stage, size of primary tumor and the largest cervical lymph node) and PET parameters were analyzed: maximum, mean and peak standardized uptake values (SUVmax, SUVmean, SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for primary tumor and largest cervical lymph node. After treatment, patients were evaluated for disease progression and mortality. Survival analysis for progression-free survival (PFS) and over-all survival (OS) was performed with Kaplan-Meier method using PET findings and clinical characteristics. RESULTS: The median follow-up duration was 29.7 months (range 3-125 months). Among clinical characteristics, no parameters had significance association for PFS. Primary tumor-MTV and cervical lymph node-MTV were independent prognostic factors for PFS (p = 0.025 and p = 0.004, respectively).Patients with primary tumor-MTV >19.4 and patients with lymph node-MTV>3.4 had shorter PFS. For OS, age and the size of the lymph node were independent prognostic factor (p = 0.031 and p = 0.029).Patients with age over 54 years and patients with lymph node size >1 cm were associated with decreased OS. CONCLUSION: Primary tumor-MTV and lymph node-MTV on pre-treatment PET/CT are significant prognostic factors for long-term PFS in non-metastatic nasopharyngeal carcinoma. We consider that measuring MTV as volume-based metabolic parameter on pretreatment PET/CT may contribute decision of treatment intensity and individualized risk stratification and may improve long-term PFS. Additionally, age and the size of lymph node are independent prognostic factors for mortality.

A Rare Extramedullary Involvement Site in Patients With Multiple Myeloma: Stomach.

ABSTRACT: Multiple myeloma (MM) is a hematologic malignancy associated with uncontrolled clonal proliferation of plasma cells. Extramedullary disease in MM is an aggressive entity with a poor prognosis. Moreover, involvement of the gastrointestinal tract is a rare aggressive biological sign. 18 F-FDG PET/CT is an irreplaceable modality in the assessment of extramedullary disease. We present 2 cases with gastric involvement of MM that were shown by 18 F-FDG PET/CT and confirmed as plasma cell infiltration pathologically. 18 F-FDG PET/CT studies of MM patients should be interpreted carefully for gastrointestinal involvement, and it should be kept in mind that it can mimic other malignancies.

A rare case describing catastrophic destruction of the whole skeleton caused by severe hyperparathyroidism.

Osteitis fibrosa cystica is a skeletal disorder seen in advanced stages of persistent hyperparathyroidism. Although the measurement of serum Ca and intact-parathormone levels provides early diagnosis and decreases the incidence of radiographic bone involvement, progressive major bone lesions may still be seen in developing countries even in the modern era. We aimed to share, by writing up this report, our astonishment after observing how the skeletal system can be ruined by persistent hyperparathyroidism.