Predictive value of SUVmax from initial 18F-FDG PET/CT scans for treatment outcomes in endometrial cancer patients undergoing fertility sparing management.

OBJECTIVE: To evaluate whether the maximum standardized uptake value (SUVmax) from initial 18F-FDG PET/CT (fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography) scans could be a predictor of complete response and recurrence in patients with endometrial cancer who are undergoing fertility sparing management. METHODS: We conducted a retrospective review of patients who were diagnosed with endometrial cancer through biopsy and chose to undergo fertility sparing management using progestin at the Asan Medical Center, from January 2011 to December 2020. Of these, 113 patients who had an 18-FDG-PET/CT scan before starting treatment were included in our study. We measured SUVmax and examined its correlation with complete response and time to progression after achieving complete response to progestin therapy. RESULTS: Of 113 patients, 73 (64.6%) achieved a complete response through fertility sparing management. The receiver operating characteristic curve analysis revealed that the optimal cut-off value of SUVmax for predicting complete response was 6.2 (sensitivity 79.5%, specificity 57.5%, p=0.006). After analyzing recurrence in the 73 patients who achieved complete response, we found that patients with an SUVmax value >6.2 had a significantly shorter time to progression compared with those with a value <6.2. (p=0.04). CONCLUSIONS: SUVmax values of PET-CT, along with other clinicopathological parameters, could be used to predict treatment response and recurrence risk in patients with stage I endometrial cancer undergoing fertility sparing management.

Diagnostic performance of a deep-learning model using 18F-FDG PET/CT for evaluating recurrence after radiation therapy in patients with lung cancer.

OBJECTIVE: We developed a deep learning model for distinguishing radiation therapy (RT)-related changes and tumour recurrence in patients with lung cancer who underwent RT, and evaluated its performance. METHODS: We retrospectively recruited 308 patients with lung cancer with RT-related changes observed on 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) performed after RT. Patients were labelled as positive or negative for tumour recurrence through histologic diagnosis or clinical follow-up after 18F-FDG PET/CT. A two-dimensional (2D) slice-based convolutional neural network (CNN) model was created with a total of 3329 slices as input, and performance was evaluated with five independent test sets. RESULTS: For the five independent test sets, the area under the curve (AUC) of the receiver operating characteristic curve, sensitivity, and specificity were in the range of 0.98-0.99, 95-98%, and 87-95%, respectively. The region determined by the model was confirmed as an actual recurred tumour through the explainable artificial intelligence (AI) using gradient-weighted class activation mapping (Grad-CAM). CONCLUSION: The 2D slice-based CNN model using 18F-FDG PET imaging was able to distinguish well between RT-related changes and tumour recurrence in patients with lung cancer.

Performance of deep learning models for response evaluation on whole-body bone scans in prostate cancer.

OBJECTIVE: We aimed to develop deep learning classifiers for assessing therapeutic response on bone scans of patients with prostate cancer. METHODS: A set of 3791 consecutive bone scans coupled with their last previous scan (1528 patients) was evaluated. Bone scans were labeled as "progression" or "nonprogression" on the basis of clinical reports and image review. A 2D-convolutional neural network architecture was trained with three different preprocessing methods: 1) no preprocessing (Raw), 2) spatial normalization (SN), and 3) spatial and count normalization (SCN). Data were allocated into training, validation, and test sets in the ratio of 72:8:20, with the 20% independent test set rotating all scans over a five-fold testing procedure. A Grad-CAM algorithm was employed to generate class activation maps to visualize the lesions contributing to the decision. Diagnostic performance was compared using area under the receiver operating characteristics curves (AUCs). RESULTS: The data consisted of 791 scans labeled as "progression" and 3000 scans labeled as "nonprogression." The AUCs of the classifiers were 0.632-0.710 on the Raw dataset, were significantly higher with the use of SN at 0.784-0.854 (p < 0.001 for Raw versus SN), and higher still with SCN at 0.954-0.979 (p < 0.001 for SN versus SCN). Class activation maps of the SCN model visualized lesions contributing to the model's decision of progression. CONCLUSION: With preprocessing of spatial and count normalization, our deep learning model achieved excellent performance in classifying the therapeutic response of bone scans in patients with prostate cancer.

Application of preoperative fluorodeoxyglucose-PET/CT parameters for predicting prognosis of high-grade neuroendocrine cervical cancer.

OBJECTIVE: High-grade neuroendocrine cervical cancer (HGNECC) is a rare and aggressive cervical cancer subtype. In this study, we aimed to evaluate the prognostic value of fluorodeoxyglucose-PET/computed tomography (CT) parameters for HGNECC. MATERIALS AND METHODS: This single-center retrospective study included 29 patients with HGNECC who underwent fluorodeoxyglucose-PET/CT scan followed by surgery between 2006 and 2016. RESULTS: The median follow-up period was 40 (range, 4-184) months. After surgery, the resection margins were tumor-negative in 28 patients (96.6%), 8 (27.6%) patients had parametrial tumor invasion, and 7 patients (24.1%) tested positive for lymph node metastasis. The tumor recurred in 20 patients (69%) and 18 patients (62.1%) died during the observation period. In the univariate analyses, age and total lesion glycolysis (TLG) were associated with worse disease-free survival (DFS) (age, hazard ratio 1.056, 95% CI 1.014-1.100, P  = 0.009; TLG2.5, hazard ratio 1.003, 95% CI 1-1.006, P  = 0.033; and TLG3.0, hazard ratio 1.003, 95% CI 1-1.006, P  = 0.034). In the multivariate analyses, older age and higher TLG3.0 were identified as independent poor prognostic factors for DFS (age, hazard ratio 1.058, 95% CI 1.014-1.104, P  = 0.009; TLG3.0, hazard ratio 1.004, 95% CI 1-1.007, P  = 0.033), while resection margin involvement was identified as an independent factor to predict poor overall survival (hazard ratio 20.717, 95% CI 1.289-332.964, P  = 0.032). CONCLUSION: Among the preoperative fluorodeoxyglucose-PET/CT parameters, TLG3.0 may be useful for predicting DFS in patients with HGNECC.

Diagnostic performance of deep learning models for detecting bone metastasis on whole-body bone scan in prostate cancer.

PURPOSE: We evaluated the performance of deep learning classifiers for bone scans of prostate cancer patients. METHODS: A total of 9113 consecutive bone scans (5342 prostate cancer patients) were initially evaluated. Bone scans were labeled as positive/negative for bone metastasis using clinical reports and image review for ground truth diagnosis. Two different 2D convolutional neural network (CNN) architectures were proposed: (1) whole body-based (WB) and (2) tandem architectures integrating whole body and local patches, here named as "global-local unified emphasis" (GLUE). Both models were trained using abundant (72%:8%:20% for training:validation:test sets) and limited training data (10%:40%:50%). The allocation of test sets was rotated across all images: therefore, fivefold and twofold cross-validation test results were available for abundant and limited settings, respectively. RESULTS: A total of 2991 positive and 6142 negative bone scans were used as input. For the abundant training setting, the receiver operating characteristics curves of both the GLUE and WB models indicated excellent diagnostic ability in terms of the area under the curve (GLUE: 0.936-0.955, WB: 0.933-0.957, P > 0.05 in four of the fivefold tests). The overall accuracies of the GLUE and WB models were 0.900 and 0.889, respectively. With the limited training setting, the GLUE models showed significantly higher AUCs than the WB models (0.894-0.908 vs. 0.870-0.877, P < 0.0001). CONCLUSION: Our 2D-CNN models accurately classified bone scans of prostate cancer patients. While both showed excellent performance with the abundant dataset, the GLUE model showed higher performance than the WB model in the limited data setting.

Deep learning detection of prostate cancer recurrence with 18F-FACBC (fluciclovine, Axumin®) positron emission tomography.

PURPOSE: To evaluate the performance of deep learning (DL) classifiers in discriminating normal and abnormal 18F-FACBC (fluciclovine, Axumin®) PET scans based on the presence of tumor recurrence and/or metastases in patients with prostate cancer (PC) and biochemical recurrence (BCR). METHODS: A total of 251 consecutive 18F-fluciclovine PET scans were acquired between September 2017 and June 2019 in 233 PC patients with BCR (18 patients had 2 scans). PET images were labeled as normal or abnormal using clinical reports as the ground truth. Convolutional neural network (CNN) models were trained using two different architectures, a 2D-CNN (ResNet-50) using single slices (slice-based approach) and the same 2D-CNN and a 3D-CNN (ResNet-14) using a hundred slices per PET image (case-based approach). Models' performances were evaluated on independent test datasets. RESULTS: For the 2D-CNN slice-based approach, 6800 and 536 slices were used for training and test datasets, respectively. The sensitivity and specificity of this model were 90.7% and 95.1%, and the area under the curve (AUC) of receiver operating characteristic curve was 0.971 (p < 0.001). For the case-based approaches using both 2D-CNN and 3D-CNN architectures, a training dataset of 100 images and a test dataset of 28 images were randomly allocated. The sensitivity, specificity, and AUC to discriminate abnormal images by the 2D-CNN and 3D-CNN case-based approaches were 85.7%, 71.4%, and 0.750 (p = 0.013) and 71.4%, 71.4%, and 0.699 (p = 0.053), respectively. CONCLUSION: DL accurately classifies abnormal 18F-fluciclovine PET images of the pelvis in patients with BCR of PC. A DL classifier using single slice prediction had superior performance over case-based prediction.

Feasibility and effectiveness of treatment strategy of tandem high-dose chemotherapy and autologous stem cell transplantation in combination with 131 I-MIBG therapy for high-risk neuroblastoma.

This study was performed to evaluate the safety and effectiveness of tandem HDCT/ASCT combined with targeted radiotherapy using 131 I-MIBG for high-risk neuroblastoma. Patients with high-risk neuroblastoma were treated with 8 to 10 cycles of induction chemotherapy before tandem HDCT/ASCT. Patients received 131 I-MIBG treatment before the second HDCT/ASCT. Local radiotherapy and maintenance therapy were performed after tandem HDCT/ASCT. Between 2012 and 2016, 19 patients were diagnosed with high-risk neuroblastoma in our institution and 18 of them received tandem HDCT/ASCT combined with 131 I-MIBG therapy. For the first HDCT/ASCT regimen, 12 patients received busulfan/melphalan and six patients received melphalan/etoposide/carboplatin. The second HDCT included ThioCy. The median dose of 131 I-MIBG was 17.2 mCi/kg for the first eight patients, while 12 patients in the latter period of the study received reduced dose of 10.7 mCi/kg. The 5-year OS and EFS rates were 79% and 61%, respectively, for all 19 patients with high-risk neuroblastoma, and 83% and 64%, respectively, for 18 patients who completed tandem HDCT/ASCT combined with 131 I-MIBG therapy. Six patients experienced disease relapse and five patients died. Treatment-related mortality was not observed. Among 15 evaluable patients, 11 patients (73%) developed hypothyroidism, six patients (40%) had CKD, and six patients (40%) had growth failure. Hypothyroidism and growth failure were less frequent in patients who received reduced doses of 131 I-MIBG therapy. Tandem HDCT/ASCT combined with HD 131 I-MIBG therapy could be feasible for patients with high-risk neuroblastoma with acceptable toxicity profiles and favorable outcomes.

Clinicopathologic risk factors of radioactive iodine therapy based on response assessment in patients with differentiated thyroid cancer: a multicenter retrospective cohort study.

PURPOSE: We investigated whether predictive clinicopathologic factors can be affected by different response criteria and how the clinical usefulness of radioactive iodine (RAI) therapy should be evaluated considering variable factors in patients with differentiated thyroid carcinoma (DTC). METHODS: A total of 1563 patients with DTC who underwent first RAI therapy after total or near total thyroidectomy were retrospectively enrolled from 25 hospitals. Response to therapy was evaluated with two different protocols based on combination of biochemical and imaging studies: (1) serum thyroglobulin (Tg) and neck ultrasonography (US) and (2) serum Tg, neck US, and radioiodine scan. The responses to therapy were classified into excellent and non-excellent or acceptable and non-acceptable to minimize the effect of non-specific imaging findings. We investigated which factors were associated with response to therapy depending on the follow-up protocols as well as response classifications. Multivariate logistic regression analysis was performed to identify factors significantly predicting response to therapy. RESULTS: The proportion of patients in the excellent response group significantly decreased from 76.5 to 59.6% when radioiodine scan was added to the follow-up protocol (P < 0.001). Preparation method (recombinant human TSH vs. thyroid hormone withdrawal) was a significant factor for excellent response prediction evaluated with radioiodine scan (OR 2.129; 95% CI 1.687-2.685; P < 0.001) but was not for other types of response classifications. Administered RAI activity, which was classified as low (1.11 GBq) or high (3.7 GBq or higher), significantly predicted both excellent and acceptable responses regardless of the follow-up protocol. CONCLUSIONS: The clinical impact of factors related to response prediction differed depending on the follow-up protocol or classification of response criteria. A high administered activity of RAI was a significant factor predicting a favorable response to therapy regardless of the follow-up protocol or classification of response criteria.

Performance of 68Ga-DOTA-Conjugated Somatostatin Receptor-Targeting Peptide PET in Detection of Pheochromocytoma and Paraganglioma: A Systematic Review and Metaanalysis.

We performed a systematic review and metaanalysis of the performance of 68Ga-DOTA-conjugated somatostatin receptor-targeting peptide (68Ga-DOTA-SST) PET in the detection of pheochromocytomas and paragangliomas (PPGLs). Methods: PubMed and Embase were searched until May 8, 2018. We included studies that reported the detection rate of 68Ga-DOTA-SST PET in patients with PPGLs. Detection rates were pooled using a random-effects model. Subgroup analyses and metaregression were performed to explore the cause of heterogeneity. Results: Thirteen studies were included for qualitative synthesis. Per-lesion detection rates of 68Ga-DOTA-SST PET were consistently higher (ranging from 92% to 100%) than other imaging modalities, including 18F-fluorohydroxyphenylalanine (18F-FDOPA) PET, 18F-FDG PET, and 123/131I-metaiodobenzylguanidine (123/131I-MIBG) scintigraphy. However, in patients with polycythemia/paraganglioma syndrome, the detection rate of 68Ga-DOTA-DOTATATE PET was 35%. Nine studies (215 patients) with no specific inclusion criteria for subtype were quantitatively synthesized. The pooled detection rate was 93% (95% confidence interval [CI], 91%-95%), which was significantly higher than that of 18F-FDOPA PET (80% [95% CI, 69%-88%]), 18F-FDG PET (74% [95% CI, 46%-91%]), and 123/131I-MIBG scan (38% [95% CI, 20%-59%], P < 0.001 for all). A greater prevalence of head and neck paragangliomas was associated with higher detection rates of 68Ga-DOTA-SST PET (P = 0.0002). Conclusion:68Ga-DOTA-SST PET exhibited superior performance for lesion detection, over other functional imaging modalities, in patients with PPGLs, with the exception of polycythemia/paraganglioma syndrome. This might suggest 68Ga-DOTA-SST PET as a first-line imaging modality for the primary staging of PPGL or the restaging of PPGL with unknown genetic status.

Prognostic Value of Volumetric Parameters of Pretreatment 18F-FDG PET/CT in Esophageal Cancer: A Systematic Review and Meta-analysis.

PURPOSE: We performed a systematic review and meta-analysis on the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) derived from pretreatment F-FDG PET/CT in patients with esophageal cancer. METHODS: PubMed and EMBASE databases were searched until April 12, 2018, for studies that evaluated MTV or TLG as prognostic factors in esophageal cancer, with overall survival (OS) and event-free survival serving as the end points. Hazard ratios (HRs) were meta-analytically pooled using a random-effects model. Subgroup analyses based on the clinicopathological and PET variables were performed. RESULTS: In total, 16 studies with 1294 patients were included. The pooled HRs of MTV and TLG for OS were 2.26 (95% confidence interval [CI], 1.73-2.96) and 2.23 (95% CI, 1.73-2.87), respectively. Regarding event-free survival, the pooled HRs of MTV and TLG were 2.03 (95% CI, 1.66-2.49) and 2.57 (95% CI, 1.82-3.62), respectively. Metabolic tumor volume was found to be a significant prognostic factor for OS consistently across multiple subgroups classified based on stage, histological subtype, treatment, delineation of volume of interest, and the determination method of cutoff value, with pooled HRs ranging from 1.96 to 2.54. CONCLUSIONS: In patients with esophageal cancer, MTV and TLG derived from pretreatment F-FDG PET are significant prognostic factors. As prognostic biomarkers, volumetric metabolic parameters may bolster the role of F-FDG PET in the management of esophageal cancer.

Performance of pre-treatment ¹8F-fluorodeoxyglucose positron emission tomography/computed tomography for detecting metastasis in ovarian cancer: a systematic review and meta-analysis.

OBJECTIVE: We describe a systematic review and meta-analysis of the performance of ¹8F-fluorodeoxyglucose (¹8F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting metastasis in ovarian cancer. METHODS: MEDLINE and Embase were searched for diagnostic accuracy studies that used ¹8F-FDG PET or PET/CT for pre-treatment staging, using surgical findings as the reference standard. Sensitivities and specificities were pooled and plotted in a hierarchic summary receiver operating characteristic plot. Potential causes of heterogeneity were explored through sensitivity analyses. RESULTS: Eight studies with 594 patients were included. The overall pooled sensitivity and specificity for metastasis were 0.72 (95% confidence interval [CI]=0.61-0.81) and 0.93 (95% CI=0.85-0.97), respectively. There was considerable heterogeneity in sensitivity (I²=97.57%) and specificity (I²=96.74%). In sensitivity analyses, studies that used laparotomy as the reference standard showed significantly higher sensitivity and specificity (0.77; 95% CI=0.67-0.87 and 0.96; 95% CI=0.92-0.99, respectively) than those including diagnostic laparoscopy (0.62; 95% CI=0.46-0.77 and 0.84; 95% CI=0.69-0.99, respectively). Higher specificity was shown in studies that confirmed surgical findings by pathologic evaluation (0.95; 95% CI=0.90-0.99) than in a study without pathologic confirmation (0.69; 95% CI=0.24-1.00). Studies with a lower prevalence of the FDG-avid subtype showed higher specificity (0.97; 95% CI=0.94-1.00) than those with a greater prevalence (0.89; 95% CI=0.80-0.97). CONCLUSION: Pre-treatment ¹8F-FDG PET/CT shows moderate sensitivity and high specificity for detecting metastasis in ovarian cancer. With its low false-positive rate, it can help select surgical approaches or alternative treatment options.

A systematic review of the prognostic value of texture analysis in 18F-FDG PET in lung cancer.

OBJECTIVE: The aim of this study was to perform a systematic review of the prognostic value of texture parameters derived by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in patients with lung cancer. METHODS: PubMed and EMBASE databases were searched up to March 12, 2018, for original articles involving texture analysis for the prediction of prognosis in patients with lung cancer. Risk of bias in the studies was critically assessed using the QUIPS tool. The results of survival analysis in the included studies were compared. RESULTS: Of the 446 articles retrieved, 17 studies were eligible for inclusion. Our review suggests that the prognostic value of texture parameters in lung cancer remains unproven. Most studies had a moderate to high risk of bias. Texture parameters that described prognosis were not replicated across studies. Conflicting results on hazard ratios were found among the studies. This discrepancy is partly explained by false-positive findings originating from statistical error and variability caused by different methodologies used for image acquisition and processing in the included studies. CONCLUSION: Based on currently available evidence, there is insufficient evidence to support the prognostic value of texture analysis in 18F-FDG PET in lung cancer. Further studies implementing well-established methodologies and statistical evidence are warranted for proper validation of these promising imaging biomarkers.

Thyroid Incidentalomas Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography: Malignant Risk Stratification and Management Plan.

OBJECTIVE: The aims of this study were to stratify the risk of malignancy in thyroid incidentalomas detected on 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG PET/CT) using ultrasound features according to guidelines for thyroid nodules and to develop a subsequent management plan. METHODS: From a historical cohort of 96,942 consecutive patients who underwent 18F-FDG PET/CT between October 2008 and September 2015, 1342 patients with 1364 nodules underwent ultrasound evaluation for focal uptake in thyroid gland, with a final diagnosis made for 877 patients with 907 nodules, which were included in this study. Ultrasound images were retrospectively reviewed, and they were stratified according to the American Thyroid Association and Korean Thyroid Image Reporting and Data System guidelines. The calculated malignancy risks were compared with the estimated risks suggested by the guidelines. RESULTS: The overall malignancy risk of thyroid incidentalomas detected on 18F-FDG PET/CT was 54.7%. When stratified according to the American Thyroid Association guidelines, the malignancy risks of thyroid incidentalomas with high and intermediate suspicion (93.2% and 45.2%, respectively) were higher than those indicated in the guidelines. The malignancy risks of thyroid incidentalomas with low and very low suspicion (8.1% and 0%, respectively) were within the guideline ranges. These findings were also noted when thyroid incidentalomas were stratified according to the Korean Thyroid Image Reporting and Data System, and in a subgroup of nodules >1 cm. CONCLUSIONS: Ultrasound examinations can be used to stratify the malignancy risk of thyroid incidentalomas detected on 18F-FDG PET/CT. The risk of malignancy did not increase in thyroid incidentalomas with low and very low suspicion, indicating that only selective biopsies may be needed in these categories of thyroid incidentalomas.

Preoperative [18F]FDG PET/CT tumour heterogeneity index in patients with uterine leiomyosarcoma: a multicentre retrospective study.

PURPOSE: We investigated the prognostic value of the tumour heterogeneity index determined on preoperative [18F]FDG PET/CT in patients with uterine leiomyosarcoma (LMS). METHODS: We retrospectively reviewed patients with uterine LMS who underwent preoperative [18F]FDG PET/CT scans at three tertiary referral hospitals. The PET/CT parameters maximum standardized uptake value of the primary tumour (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis were assessed. The negative values of the MTV linear regression slope (nMLRS) according to the SUV thresholds of 2.5 and 3.0 were determined as the tumour heterogeneity index. The value of PET/CT-derived parameters in predicting progression-free survival (PFS) and overall survival (OS) were determined in regression analyses. RESULTS: Clinicopathological and PET/CT data from 16 patients were reviewed. The median postsurgical follow-up was 21 months (range 4-82 months), and 12 patients (75.0%) experienced recurrence. Tumour size (P = 0.017), SUVmax (P = 0.019), MTV (P = 0.016) and nMLRS (P = 0.008) were significant prognostic factors for recurrence. MTV (P = 0.048) and nMLRS (P = 0.045) were significant prognostic factors for patient survival. nMLRS was correlated with clinicopathological parameters including tumour size (Pearson's correlation coefficient γ = 0.825, P < 0.001) and lymph node metastasis (γ = 0.721, P = 0.004). Patient groups categorized according to the nMLRS cut-off value showed significant differences in PFS (P = 0.033) and OS (P = 0.044). CONCLUSION: The preoperative tumour heterogeneity index obtained using the MTV linear regression slope may be a novel and useful prognostic marker in uterine LMS.

Diagnostic value of integrated ¹8F-fluoro-2-deoxyglucose positron emission tomography/computed tomography in recurrent epithelial ovarian cancer: accuracy of patient selection for secondary cytoreduction in 134 patients.

OBJECTIVE: The aim of this study was to evaluate the diagnostic value of integrated ¹8F-fluoro-2-deoxyglucose-positron emission tomography/computed tomography (¹8F-FDG-PET/CT) for suspected recurrence of epithelial ovarian cancer (EOC) with non-disseminated lesions. METHODS: We retrospectively reviewed the medical records of recurrent EOC patients who underwent secondary cytoreduction from January 2000 to December 2013. A total of 134 patients underwent secondary cytoreduction after imaging with either ¹8F-FDG-PET/CT or contrast-enhanced computed tomography (CECT). RESULTS: In a patient-based analysis of 134 patients, 124 (92.5%) were confirmed to be positive for malignancy. Among 72 patients with suspected non-disseminated recurrence on ¹8F-FDG-PET/CT, 65 (89.0%) were confirmed to have recurrence, giving 98.5% sensitivity, 87.7% accuracy, and 88.9% positive predictive value (PPV). In the 65 patients with recurrence, residual tumor remained in 14 patients, giving an accuracy of patient selection for secondary cytoreduction of 69.4% (50/72) and it is higher than that of CECT (64.0%). In 169 lesions removed from patients who underwent preoperative ¹8F-FDG-PET/CT, 135 (79.9%) were confirmed to be positive for malignancy and 124 were accurately detected by ¹8F-FDG-PET/CT, giving 91.9% sensitivity, 81.1% accuracy, and 85.5% PPV. Foreign body granuloma was found in 33.3% of 21 lesions with false-positive ¹8F-FDG-PET/CT findings (7/21). The mean preoperative cancer antigen 125 (CA-125) level in false-positive patients was 28.8 U/mL. CONCLUSION: Compared with CECT, ¹8F-FDG-PET/CT shows higher sensitivity in lesion-based analysis and better accuracy of patient selection for secondary cytoreduction. However, there is still a need for integration of the results of ¹8F-FDG-PET/CT, CECT, and CA-125 levels to aid treatment planning.

Comparison of Core-Needle Biopsy and Fine-Needle Aspiration for Evaluating Thyroid Incidentalomas Detected by 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: A Propensity Score Analysis.

BACKGROUND: This study used a propensity score analysis to assess the roles of core-needle biopsy (CNB) and fine-needle aspiration (FNA) in the evaluation of thyroid incidentalomas detected on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). METHODS: The study population was obtained from a historical cohort who underwent 18F-FDG PET/CT between October 2008 and September 2015. Patients were included who underwent ultrasound-guided CNB or FNA for incidental focal uptake of 18F-FDG in the thyroid gland on PET/CT. The primary study outcomes included the inconclusive result rates in the CNB and FNA groups. The secondary outcome measures included the non-diagnostic result rate and the diagnostic performance for neoplasms. Multivariate analysis, propensity score matching, and inverse probability weighting were conducted. RESULTS: A total of 1360 nodules from 1338 patients were included in this study: 859 nodules from 850 patients underwent FNA, and 501 nodules from 488 patients underwent CNB. Compared to FNA, CNB demonstrated a significantly lower inconclusive result rate in the pooled cohort (23.8% vs. 35.4%; p < 0.001), propensity score-matched cohorts (22.9% vs. 36.6%; p < 0.001), and with inverse probability weighting (22.4% vs. 35.2%; p < 0.001). Non-diagnostic result rates were also significantly lower in CNB than in FNA. The diagnostic performance of the two groups in the pooled and matched cohorts was similar, with no significant differences found. CONCLUSIONS: The significantly lower inconclusive result rates in CNB than in FNA were consistent within the propensity score-matched cohorts. Therefore, CNB appears to be a promising diagnostic tool for patients with thyroid incidentalomas detected on 18F-FDG PET/CT.

Endoscopic biliary stent insertion through specialized duodenal stent for combined malignant biliary and duodenal obstruction facilitated by stent or PTBD guidance.

OBJECTIVES: Endoscopic stenting for combined malignant biliary and duodenal obstruction is technically demanding. However, this procedure can be facilitated when there is guidance from previously inserted stent or PTBD tube. This study aimed to evaluate the feasibility and clinical success rate of endoscopic placement of biliary self-expandable metal stent (SEMS) through duodenal SEMS in patients with combined biliary and duodenal obstruction due to inoperable or metastatic periampullary malignancy. MATERIALS AND METHODS: A total of 12 patients with combined malignant biliary and duodenal stricture underwent insertion of biliary SEMS through the mesh of specialized duodenal SEMS from July 2012 to October 2016. Technical and clinical success rate, adverse events and survival after completion of SEMS insertion were evaluated. RESULTS: The duodenal strictures were located in the first portion of the duodenum in four patients (Type I), in the second portion in three patients (Type II), and in the third portion in five patients (Type III). Technical success rate of combined metallic stenting was 91.7%. Insertion of biliary SEMS was guided by previously inserted biliary SEMS in nine patients, plastic stent in one patient, and PTBD in two patients. Clinical success rate was 90.9%. There were no early adverse events after the procedure. Mean survival period after combined metallic stenting was 91.9 days (range: 15-245 days). CONCLUSIONS: Endoscopic placement of biliary SEMS through duodenal SEMS is feasible with high success rates and relatively easy when there is guidance. This method can be a good alternative for palliation in patients with combined biliary and duodenal obstruction.

Prognostic value of metabolic parameters determined by preoperative ¹8F-FDG PET/CT in patients with uterine carcinosarcoma.

OBJECTIVE: To evaluate the prognostic value of metabolic parameters measured by preoperative ¹8F-fluorodeoxyglucose (¹8F-FDG) positron emission tomography (PET)/computed tomography (CT) in patients with uterine carcinosarcoma (UCS). METHODS: Data of 55 eligible patients with UCS who underwent preoperative ¹8F-FDG PET/CT and surgical staging were analyzed retrospectively. Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV2.5), and total lesion glycolysis (TLG2.5) of the primary tumors were measured using a SUV threshold of 2.5. The optimal cutoff value of each parameter was determined by time-dependent receiver operating characteristic curve, and its impact on progression-free survival and overall survival was evaluated by Cox proportional hazards model. RESULTS: During a median follow-up period of 29 (range, 1.5-109.4) months, 47.3% (26/55) of the patients experienced disease progression, and the disease-associated mortality rate was 43.6% (24/55). Univariate analysis determined that hazard ratios (HRs) for disease progression for SUVmax (≥8.33), MTV2.5 (≥63.92 mL), and TLG2.5 (≥396.16) were 1.930 (95% confidence interval [CI]=0.793-4.701), 3.264 (95% CI=1.466-7.268), and 2.692 (95% CI=1.224-5.924), respectively. And, HRs for death were 1.979 (95% CI=0.774-5.060), 2.764 (95% CI=1.217-6.274), and 2.721 (95% CI=1.198-6.182), respectively. While peritoneal cytology, histology, and tumor diameter were independent prognostic factors in multivariate analysis, MTV and TLG were not. CONCLUSION: Though MTV and TLG of primary UCS were not independent predictors compared to surgically obtained data, MTV and TLG of primary UCS may provide useful information on prognosis especially in patients who are not able to undergo surgical staging.

The Value of Preoperative Positron Emission Tomography/Computed Tomography in Node-Negative Endometrial Cancer on Magnetic Resonance Imaging.

OBJECTIVE: The aim of this study was to investigate the value of [18F]fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in predicting lymph node status in node-negative endometrial cancer on preoperative magnetic resonance imaging (MRI). METHODS: Patients with endometrial cancer who underwent both preoperative MRI and FDG-PET/CT followed by hysterectomy and lymphadenectomy were initially included. We then enrolled patients with MRI-defined node-negative disease (lymph nodes <1 cm in the short-axis diameter, or no visible lymph node). Histologic examination was the gold standard for lymph node metastasis diagnosis. The diagnostic performance of FDG-PET/CT in predicting lymph node metastasis was calculated in patient-by-patient and lymph node station-by-station analyses. RESULTS: On preoperative MRI, 362 patients had no lymph node metastasis. All patients underwent pelvic lymph node dissection and 118 patients underwent further para-aortic lymph node dissection. From 2099 lymph node stations, 10,238 lymph nodes were retrieved. Twenty-seven patients (7.5%) had lymph node metastasis in 49 lymph node stations (2.3%) on pathologic examination. FDG-PET/CT identified lymph node metastasis in five patients (18.5%) and eight lymph node stations (16.3%). The median diameter of false-negative metastatic lymph nodes was 6 mm (range 1-22) in the long axis and 3 mm (range 1-11) in the short axis. For para-aortic lymph nodes, FDG-PET/CT diagnosed 2 of 11 patients (18.1%) with para-aortic lymph node metastasis, and 3 of 12 para-aortic lymph node stations (25%) with metastasis. CONCLUSION: Preoperative FDG-PET/CT has low value in predicting lymph node metastasis in node-negative endometrial cancer on preoperative MRI.

Prognostic significance of preoperative ¹8F-FDG PET/CT in uterine leiomyosarcoma.

OBJECTIVE: Uterine leiomyosarcoma (LMS) is a rare and aggressive disease with poor outcome. Due to its rarity and conflict of data, investigation on finding prognostic factor is challenging. The aim of the study was to investigate the prognostic significance of preoperative ¹8F-fluorodeoxyglucose (¹8F-FDG) positron emission tomography/computed tomography (PET/CT) in uterine LMS. METHODS: This was a retrospective observational cohort study in 3 tertiary referral hospitals. We retrospectively evaluated data from patients with pathologically proven uterine LMS who underwent preoperative ¹8F-FDG PET/CT scans at 3 institutions. The prognostic implication of PET/CT parameters and other clinico-pathological parameters on disease-free survival (DFS) and overall survival (OS) was evaluated. RESULTS: Clinico-patholgical data were reviewed for 19 eligible patients. In the group overall, median DFS and OS were 12 and 20 months, respectively. As for the recurrence, large tumor size, and high tumor maximum standardized uptake value (SUVmax) were demonstrated as risk factors of recurrence. As for the OS, high tumor SUVmax was demonstrated as the unique risk factor. There were significant differences in tumor size, mitotic count, SUVmax, and DFS between patients with and without recurrence. Also, there were significant differences in tumor size, SUVmax, DFS, and OS between 2 subgroups stratified by cut-off SUVmax. CONCLUSION: SUVmax at preoperative ¹8F-FDG PET/CT was associated with worse outcome in patients with uterine LMS. In the preoperative setting, SUVmax can be a valuable non-invasive prognostic marker. Additionally, SUVmax can help identify highly aggressive uterine LMS and may help in adjusting standard treatment toward an individualized, risk-adapted treatment.