Diagnostic Performance of Response Assessment FDG-PET/CECT in HNSCC Treated With Definitive Radio(chemo)therapy Using NI-RADS.

OBJECTIVE: To assess the diagnostic performance of response assessment 18F-fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography (FDG-PET/CECT) following definitive radio(chemo)therapy in head and neck squamous cell carcinoma (HNSCC) using Neck Imaging Reporting and Data System (NI-RADS). STUDY DESIGN: A retrospective analysis from a prospectively maintained dataset. SETTING: Tertiary-care comprehensive cancer center in a low-middle-income country. METHODS: Adults with newly diagnosed, biopsy-proven, nonmetastatic HNSCC treated with definitive radio(chemo)therapy were included. Posttreatment response assessment FDG-PET/CECT scans were retrospectively assigned NI-RADS categories (1-3) for the primary site, neck, and both sites combined. Locoregional recurrence occurring within 2-years was defined as the event of interest. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were calculated. Locoregional control stratified by NI-RADS categories was computed with the Kaplan-Meier method and compared using the log-rank test. RESULTS: Posttreatment FDG-PET/CECT scans were available in 190 patients constituting the present study cohort. Sensitivity, specificity, PPV, NPV, and overall accuracy of the NI-RADS template for the primary site was 73.5%, 81.4%, 46.3%, 93.4%, and 80.0%, respectively. Similar metrics for the neck were 72.7%, 87.5%, 43.2%, 96.1%, and 85.8%, respectively. Combining primary site and neck, the corresponding metrics of diagnostic accuracy were 84.4%, 69.7%, 46.3%, 93.5%, and 73.2%, respectively. At a median follow-up of 40 months, Kaplan-Meier estimates of 2-year locoregional control were significantly higher for NI-RADS category 1 (94.2%) compared to NI-RADS category 2 (69.4%) and category 3 (20.4%), respectively (stratified log-rank p < .0001). CONCLUSION: FDG-PET/CECT using the NI-RADS template is associated with good diagnostic performance and prognostic utility in HNSCC treated with definitive radio(chemo)therapy.

68 Ga-DOTATATE PET/CT imaging in endogenous hyperinsulinemic hypoglycemia: A tertiary endocrine centre experience.

OBJECTIVE: Literature regarding utility of 68 Ga-DOTATATE PET/CT in insulinoma localization across various subgroups [benign/malignant/multiple endocrine neoplasia-1 (MEN-1) syndrome associated] remains scarce. In this study, the performance of 68 Ga-DOTATATE PET/CT was compared with contrast-enhanced computed tomography (CECT) and 68 Ga-NODAGA-Exendin-4 PET/CT (whenever available) in an endogenous hyperinsulinemic hypoglycemia (EHH) cohort. DESIGN: Retrospective audit. PATIENTS: EHH patients [N = 36, lesions (n) = 49, final diagnosis: benign sporadic insulinoma (BSI) (N = 20), malignant insulinoma (N = 4, n = 14), MEN-1 syndrome associated insulinoma (N = 9, n = 15), Munchausen syndrome (N = 2) and drug-induced hypoglycemia (N = 1)] having both preoperative imaging modalities (CECT and 68 Ga-DOTATATE PET/CT). MEASUREMENTS: Per-lesion sensitivity (Sn) and positive predictive value (PPV) for histopathological diagnosis of insulinoma. RESULTS: Sn and PPV of 68 Ga-DOTATATE PET/CT were 67.3% and 89.2%; 55% and 100%; 85.7% and 100%; and 66.7% and 77% for overall EHH, BSI, malignant, and MEN-1 syndrome associated insulinoma cohorts respectively. Despite having comparatively lower sensitivity in BSI cohort, 68 Ga-DOTATATE PET/CT localized a pancreatic tail lesion missed by other modalities. 68 Ga-DOTATATE PET/CT had comparatively higher sensitivity in malignant insulinoma than BSI cohort. 68 Ga-DOTATATE PET/CT also paved the way for successful response to 177 Lu-based peptide receptor radionuclide therapy (PRRT). In MEN-1 cases, lower PPV as compared with BSI was due to uptake in non-insulinoma pancreatic neuroendocrine tumours (Pan-NET). CONCLUSIONS: 68 Ga-DOTATATE PET/CT has supplemental role in selected cases of BSI with negative and/or discordant results with CECT and 68 Ga-NODAGA-Exendin-4 PET/CT. In malignant insulinoma, 68 Ga-DOTATATE-PET/CT has an additional theranostic potential. Interference due to uptake in non-insulinoma Pan-NET in MEN-1 syndrome may hinder insulinoma localization with 68 Ga-DOTATATE-PET/CT.

Is Skeletal Imaging Essential in the Staging Workup for Conventional Chondrosarcoma?

BACKGROUND: Staging of a bone sarcoma before initiating treatment helps orthopaedic oncologists determine the intent of treatment and predicting the prognosis. As per National Comprehensive Cancer Network (NCCN) and European Society for Medical Oncology (ESMO) guidelines, there are no exclusive recommendations for chondrosarcoma staging. They are staged similar to other bone sarcomas even though skeletal metastases are extremely rare in chondrosarcomas. QUESTIONS/PURPOSES: We asked: (1) What proportion of patients with a chondrosarcoma present with detectable only skeletal metastasis? (2) What proportion of patients with chondrosarcoma present with skeletal metastasis with or without concurrent pulmonary metastases? METHODS: Between January 2006 to December 2017, 480 patients with histology-proven chondrosarcomas of the extremity, including clavicle, scapula, spine, and pelvis, presented to our institute. Fifty-three patients were excluded due to incomplete details about their staging. The remaining 427 were retrospectively analyzed and included in this study. Their clinical, radiological, and histopathological details were retrieved from patient files and electronic medical records. Of the 427 patients included, 53 had Grade 1 chondrosarcoma, 330 had Grade 2 chondrosarcoma, and 41 had Grade 3 chondrosarcoma. Grade was not available in three patients. All patients were staged with a thoracic CT scan and bone scan or a whole body fluorodeoxyglucose positron-emission tomography/CT (FDG PET/CT). Patients with a suspected or documented metastasis were reviewed again by an experienced radiologist and a nuclear medicine expert for the purpose of this study. A total of 8% (35 of 427) of patients with chondrosarcoma had isolated lung metastases at the time of initial staging. These included 9% (31 of 330) of patients with Grade 2 chondrosarcomas and 10% (4 of 41) of patients with Grade 3 chondrosarcomas. No patient with a Grade 1 chondrosarcoma had detectable lung metastases. The primary study endpoint was the number of patients who had a diagnosis of skeletal or skeletal and lung metastases as identified by the staging modalities. RESULTS: Three patients with Grade 2 chondrosarcoma had only skeletal metastasis. No patients with Grade 1 or Grade 3 chondrosarcoma had detectable bone metastases. Combined lung and bone metastases were seen in only two patients with Grade 2 chondrosarcoma. CONCLUSIONS: Our study found that the incidence of bony metastasis in conventional chondrosarcomas is extremely low. Considering the present results, we believe skeletal scanning may be overused in current staging algorithms. We do not have survival outcomes to know if detecting these few patients with skeletal lesions at initial presentation would be important in the absence of symptoms, but our data suggest that omitting skeletal imaging from the staging work-up of conventional chondrosarcomas should be considered. It may be reserved for patients with documented pulmonary metastases. LEVEL OF EVIDENCE: Level IV, diagnostic study.

Assessment of the impact of 2015 American Thyroid Association guidelines in management of differentiated thyroid cancer patients.

The 2015 American Thyroid Association (ATA) guideline have suggested modifications in the risk stratification (RS) for differentiated thyroid cancer (DTC) patients, introduced the concept of dynamic risk stratification (DRS) and redefined the role of radioactive iodine (RAI) in treatment algorithm. The aim of this retrospective audit was to assess the practical implications of these modifications in management of DTC. METHODS: A total of 138 DTC patients were stratified according to ATA 2009 and 2015 guidelines into low (LR), intermediate (IR) and high (HR) risk groups. Change in RS and in intention of RAI use was calculated. Deviation in administered RAI dosage from the guidelines was assessed. 1-year follow-up data was audited to assess how the DRS modified the initial risk estimate. RESULTS: A total of 11.6% of patients changed their RS categories in 2015 guidelines. A total of 10.1% got upstaged to HR, and 1.4% got downstaged to LR. In 2.17% of patients' intention of RAI use changed to remnant ablation from adjuvant therapy and 65% of the LR patients won't require any RAI therapy. A total of 26.7% of patients had received significantly more RAI dosage according to ATA 2015. At 1-year follow-up according to DRS 84% of LR, 75% of IR and 44% of HR patients showed excellent response (ER). CONCLUSION: More patients changed RS to HR than to LR. Intention of RAI use changed in only a small number of patients. Significantly higher dosage of RAI is being administered to patients in current practice. The effect of DRS in modifying the initial RS was most prominent in IR, with most showing ER to initial therapy.