Rare Cases of Extracranial Metastases from High-grade Glioma Detected on FET PET-CT with Histopathological Confirmation.

Extracranial metastasis from high-grade glial tumors is an extremely rare condition with its reported incidence being <1%. The most common sites reported in the literature are leptomeninges and spinal cord, followed by the liver, lung, and skeletal system. Its low incidence is thought to be related to the intrinsic aggressive biology of the tumor, thus reducing median overall survival in patients. As there is lack of knowledge about the mechanism of extracranial spread of glioma cells, its diagnosis and management remain a major challenge. We report two cases of extracranial metastases from glial tumors to cervical nodes and postoperative site involving preauricular region detected on F18 Fluoro ethyl tyrosine (FET) positron emission tomography-computed tomography and later on confirmed with histopathology Fluoro ethyl tyrosine.

Intra-arterial PRRT with Lu-177 DOTATATE in Liver-dominant Metastatic Neuroendocrine Tumors: Early Assessment of Efficacy and Toxicity.

Purpose: We proposed to administer Lu-177-DOTATATE in intra-arterial (IA) mode for higher first-pass localization to somatostatin receptors, higher residence time in liver metastases, and more radiation to tumor. This study aimed at assessing early hematological, renal and hepatotoxicity; and objective response to IA peptide receptor radionuclide therapy (PRRT). Materials and Methods: Fourteen patients (4 females and 10 males) were prospectively assessed. 5/14 patients underwent 2 cycles, whereas 3/14 underwent 3 cycles, and 6/14 received 1 cycle of IA PRRT. 200 mCi of Lu-177-DOTATATE was administered in 15-20 min by IA route under angiographic guidance. Patients were asked to follow-up at 4 and 8 weeks with hematological, liver, and renal functional parameters, and Ga-68 DOTATATE positron emission tomography/computed tomography (PET/CT) after 8 weeks. Response was assessed using RECIST 1.1 and EORTC PET criteria. Results: Safety: 2/14 patients had high total and direct bilirubin, which reverted to normal after IA PRRT. Three patients had low albumin, which improved after 1 cycle. Nine patients showed no worsening of liver function. Two patients showed Grade 1 hematotoxicity which reverted to normal. Five patients showed high creatinine, but preserved glomerular filtration rate and EC clearance. On follow-up at 8 weeks, serum creatinine reverted to normal. Efficacy: In five patients who underwent 2 cycles of IA PRRT, 3 showed partial response (PR) on RECIST 1.1 and partial metabolic response (PMR) on EORTC criteria, whereas 2 showed stable disease (SD). In patients who underwent 3 cycles, 1 showed SD, whereas other patient showed PMR on DOTANOC PET/CT, with PR in size. Among the remaining seven patients, 5 showed PMR, whereas the other 2 showed SD. Thus 9/14 patients showed PR, whereas 5 showed SD on metabolic and size criteria. Conclusions: IA PRRT is a safe and efficacious approach for the treatment of liver dominant metastatic neuroendocrine tumors.

A Case Series Depicting PSMA Expression in Nonmalignant Lesions.

Prostate-specific membrane antigen (PSMA) is a widely accepted and used tracer in staging and biochemical recurrences of prostate cancer. PSMA is extensively expressed in normal prostatic epithelial cells and prostate cancer cells, with some amount of expression also in nonprostatic cells. False-positive PSMA uptake in nonmalignant lesions creates ambiguity in disease detection. In such cases, histopathological correlation and radiological follow-up assist in clinical decision-making. In this case series, we illustrate a few cases where PSMA uptake was incidentally found in some of the commonly occurring benign conditions.

PRRT with Lu-177 DOTATATE in Treatment-Refractory Progressive Meningioma: Initial Experience from a Tertiary-Care Neuro-Oncology Center.

PURPOSE: Refractory and/or recurrent meningiomas have poor outcomes, and the treatment options are limited. Peptide receptor radionuclide therapy (PRRT) has been used in this setting with promising results. We have documented our experience of using intravenous (IV) and intra-arterial (IA) approaches of Lu-177 DOTATATE PRRT. METHODS: Eight patients with relapsed/refractory high-grade meningioma received PRRT with Lu-177 DOTATATE by IV and an IA route. At least 2 cycles were administered. Time to progression was calculated from the first PRRT session to progression. The response was assessed on MRI using RANO criteria, and visual analysis of uptake was done on Ga-68 DOTANOC PET/CT. Post-therapy dosimetry calculations for estimating the absorbed dose were performed. RESULTS: Median time to progression was 8.9 months. One patient showed disease progression, whereas seven patients showed stable disease at 4 weeks following 2 cycles of PRRT. Dosimetric analysis showed higher dose and retention time by IA approach. No significant peri-procedural or PRRT associated toxicity was seen. CONCLUSION: PRRT is a safe and effective therapeutic option for relapsed/refractory meningioma. The IA approach yields better dose delivery and should be routinely practised.

Tata Memorial Centre Evidence Based Use of Nuclear medicine diagnostic and treatment modalities in cancer.

ABSTRACT: PET/CT and radioisotope therapy are diagnostic and therapeutic arms of Nuclear Medicine, respectively. With the emergence of better technology, PET/CT has become an accessible modality. Diagnostic tracers exploring disease-specific targets has led the clinicians to look beyond FDG PET. Moreover, with the emergence of theranostic pairs of radiopharmaceuticals, radioisotope therapy is gradually making it's way into treatment algorithm of common cancers in India. We therefore would like to discuss in detail the updates in PET/CT imaging and radionuclide therapy and generate a consensus-driven evidence based document which would guide the practitioners of Oncology.

Primary Neuroendocrine Tumor of Prostate in a Case of Metastatic Adenocarcinoma of Lung: Rare Entity with Histopathological and Gallium 68 DOTANOC Positron Emission Tomography Correlation.

Neuroendocrine tumor (NET) of the prostate is an extremely rare entity which represents <1% of the prostatic cancers, but with increasing incidence. Its spectrum encompasses several histological variants ranging from well-differentiated tumor which are often indolent in nature; to aggressive neuroendocrine carcinoma which portends aggressive management. Hence, such rare entities are to be characterized and treated accordingly. We report an unusual case of well-differentiated NET of prostate which was flagged on fluorodeoxyglucose positron emission tomography computed tomography (PET/CT) performed for other indication and confirmed on Gallium-68 DOTANOC PET/CT. Histopathology and immunohistochemistry confirmed the findings subsequently.

Clinical Concept-Based Radiology Reports Classification Pipeline for Lung Carcinoma.

Rising incidence and mortality of cancer have led to an incremental amount of research in the field. To learn from preexisting data, it has become important to capture maximum information related to disease type, stage, treatment, and outcomes. Medical imaging reports are rich in this kind of information but are only present as free text. The extraction of information from such unstructured text reports is labor-intensive. The use of Natural Language Processing (NLP) tools to extract information from radiology reports can make it less time-consuming as well as more effective. In this study, we have developed and compared different models for the classification of lung carcinoma reports using clinical concepts. This study was approved by the institutional ethics committee as a retrospective study with a waiver of informed consent. A clinical concept-based classification pipeline for lung carcinoma radiology reports was developed using rule-based as well as machine learning models and compared. The machine learning models used were XGBoost and two more deep learning model architectures with bidirectional long short-term neural networks. A corpus consisting of 1700 radiology reports including computed tomography (CT) and positron emission tomography/computed tomography (PET/CT) reports were used for development and testing. Five hundred one radiology reports from MIMIC-III Clinical Database version 1.4 was used for external validation. The pipeline achieved an overall F1 score of 0.94 on the internal set and 0.74 on external validation with the rule-based algorithm using expert input giving the best performance. Among the machine learning models, the Bi-LSTM_dropout model performed better than the ML model using XGBoost and the Bi-LSTM_simple model on internal set, whereas on external validation, the Bi-LSTM_simple model performed relatively better than other 2. This pipeline can be used for clinical concept-based classification of radiology reports related to lung carcinoma from a huge corpus and also for automated annotation of these reports.

Diagnostic performance of F-18 FDG PET/CT in recurrent adenocarcinoma gallbladder and its impact on post-recurrence survival.

PURPOSE: To analyze diagnostic performance of F-18 FDG PET/CT in recurrent adenocarcinoma gallbladder (GBC) and to establish its possible impact on post-recurrence survival. METHOD: FDG PET/CT studies of suspected recurrent GBC were retrospectively analyzed alongside tumor markers serum CEA and CA 19-9. Abnormal FDG-avid lesions and abnormal morphological lesions were considered positive for recurrence, and were categorized as isolated abdominal wall recurrence, loco-regional recurrence, and distant metastatic disease. Histopathology, definite progression on imaging and positive response to treatment was considered as reference standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were used as diagnostic performance parameters. Post-recurrence survival was calculated whenever appropriate follow-up was available, based on the abovementioned categories of sites of recurrence using survival curves and log-rank test. RESULTS: Out of 117 PET/CT studies, 93 (79.5%) were positive and 24 (20.5%) were negative for recurrence. 86 out of 93 were true positive and 23 of 24 were true negative. PET/CT demonstrated sensitivity, specificity, PPV, NPV and accuracy of 98.8%, 76.7%, 92.5%, 95.8% and 93.1%, respectively. Diagnostic performance of PET/CT was significantly better than combination tumor markers. Of 66 cases with available follow-up, isolated abdominal wall (port/scar site) recurrence and loco-regional recurrence demonstrated significantly higher post-recurrence survival as compared to distant metastasis; median survival being 39, 25 and 12 months, respectively. CONCLUSION: F-18 FDG PET/CT has better diagnostic performance than tumor markers combination. Isolated abdominal wall (port/scar site) recurrence and loco-regional recurrence on PET/CT demonstrated better survival than non-regional metastatic disease. These results suggest a possible role of PET/CT as a surveillance modality, as well as a guide to therapeutic decision-making in cases of recurrent GBC.

Sporadic Cerebellar Hemangioblastoma With Strong SSTR Expression on 68 Ga-DOTANOC PET/CT.

ABSTRACT: Sporadic cerebellar hemangioblastomas are rare with majority of these tumors presenting as a part of von Hippel-Lindau syndrome. We demonstrate an unusual case of a symptomatic sporadic cerebellar hemangioblastoma mimicking a meningioma on MRI and 68 Ga-DOTANOC PET imaging.

An Audit of Systemic Therapy in Medullary Carcinoma Thyroid.

There is a paucity of evidence of the impact of sorafenib on MCT and it is the preferred therapy used in India. We decided to do an audit of all patients of MCT who were referred to us for systemic therapy. The objective of this exercise was to identify the treatment pattern, outcomes, and adverse events with therapy in MCT. Baseline demographics (age, gender, ECOG PS, comorbidities, habits), tumor details (site of metastasis), previous treatment details, clinical features at metastasis (symptomatic or asymptomatic), the pattern of treatment, adverse events (CTCAE version 4.02), date of progression, date of death and status, and follow-up were extracted from the rare tumor database and electronic medical records. Out of 75 patients referred for therapy for MCT, 47 (62.7%) patients were considered for immediate tyrosine kinase inhibitors as they had symptomatic status and 28 (37.3%) patients were kept on observation due to the asymptomatic nature of the disease. Out of the 28 patients, 15 (53.6%, n = 28) patients were subsequently started on TKI while in 13 (46.4%, n = 28) patients observation was continued. In the overall cohort, the median PFS was 18.9 months (95% CI 11.9-29.9) and OS was 26.6 months (95% CI 14.4-39.0). Among variables tested, only female gender had an impact on PFS (hazard ratio = 0.364 95% CI 0.148-0.895; P = 0.028) and the absence of lung metastasis had a positive impact on OS (hazard ratio = 0.443 95% CI 0.207-0.95; P = 0.037). Most commonly used TKI was sorafenib (n = 61) and sunitinib in 1 patient. The most common adverse events with TKI were palmo-plantar dysesthesia (50, 80.6%) and oral mucositis (25, 40.2%). The strategy of treating symptomatic MCT and observing in asymptomatic MCT is associated with reasonable PFS and OS. Sorafenib is the most commonly used TKI in our setup and provides similar outcomes as globally.

Benign Metastasizing Leiomyoma and Findings on Fluorodeoxyglucose Positron Emission Tomography/Contrast-Enhanced Computed Tomography.

Benign metastasizing leiomyoma is a rare condition where benign smooth muscle tumors having a histological appearance similar to uterine leiomyoma are present at distant sites. This entity is commonly associated with a past history of hysterectomy done for uterine fibroids. The knowledge of the presence of significant fluorodeoxyglucose uptake in leiomyoma helped in the diagnosis of this condition in a 47-year-old patient who being evaluated for multiple unusual sites of metastases; this was further confirmed on histopathology.

Radiomics: a quantitative imaging biomarker in precision oncology.

Cancer treatment is heading towards precision medicine driven by genetic and biochemical markers. Various genetic and biochemical markers are utilized to render personalized treatment in cancer. In the last decade, noninvasive imaging biomarkers have also been developed to assist personalized decision support systems in oncology. The imaging biomarkers i.e., radiomics is being researched to develop specific digital phenotype of tumor in cancer. Radiomics is a process to extract high throughput data from medical images by using advanced mathematical and statistical algorithms. The radiomics process involves various steps i.e., image generation, segmentation of region of interest (e.g. a tumor), image preprocessing, radiomic feature extraction, feature analysis and selection and finally prediction model development. Radiomics process explores the heterogeneity, irregularity and size parameters of the tumor to calculate thousands of advanced features. Our study investigates the role of radiomics in precision oncology. Radiomics research has witnessed a rapid growth in the last decade with several studies published that show the potential of radiomics in diagnosis and treatment outcome prediction in oncology. Several radiomics based prediction models have been developed and reported in the literature to predict various prediction endpoints i.e., overall survival, progression-free survival and recurrence in various cancer i.e., brain tumor, head and neck cancer, lung cancer and several other cancer types. Radiomics based digital phenotypes have shown promising results in diagnosis and treatment outcome prediction in oncology. In the coming years, radiomics is going to play a significant role in precision oncology.

Prognostic value of lung shunt fraction in hepatocellular carcinoma and unresectable liver dominant metastatic colorectal cancer undergoing transarterial radioembolisation.

AIM: To assess the overall survival and determine whether pre-TARE shunt fraction, tumor volume and tumor marker impact the outcome. METHODS: This is a retrospective study of 75 patients who were referred for 90Y-glass microsphere radioembolisation by a joint clinic decision between 1 January 2010 and 31 December 2014. All patients underwent pre-TARE CECT and 99mTc-MAA lung shunt fraction (LSF) imaging. RESULTS: Overall survival was 19 months for hepatocellular carcinoma (HCC) and 24 months for metastatic colorectal carcinoma. For hepatocellular carcinoma-LSF higher than 6.51 % was predictive of significantly decreased survival (P value 0.00). A progressive disease in survival was observed as LSF increased from less than 6.51 % to more than 20%. Tumor volume and tumor marker did show correlation with patient outcomes. For metastatic colorectal carcinoma-LSF and tumor marker did not show significant correlation with survival and tumor volume showed significant correlation with survival with P value of 0.049.

Radiation-Induced Meningioma in a Case of Medulloblastoma Treated 11 Years Ago-Detected on 68Ga-DOTANOC PET/CT.

ABSTRACT: Medulloblastomas, especially the sonic hedgehog subgroup, are treated aggressively with surgery and chemoradiotherapy, as they are associated with high local site recurrence rate and poor overall survival. Radiation-induced meningioma is the most common delayed complication of craniospinal irradiation. This needs to be differentiated from meningeal or ependymal metastases as the later need aggressive management. We report one such rare case, in a patient who completed treatment for medulloblastoma 11 years ago, was in remission, and now presented with dural-based lesions.

All that Glitters on PSMA is Not a Lesion: An Unusual Artifact on PSMA PET/CT.

Nonspecific uptake of prostate-specific membrane antigen (PSMA) on PSMA positron-emission tomography/computed tomography (CT) is normally encountered in benign conditions, which is detected on morphological changes on CT component. However, having a site of uptake without any CT finding is a rare occurrence. We herewith report one such rare case of a 66-year-old male with metastatic prostatic adenocarcinoma, who demonstrated an incidental finding of intense focal PSMA uptake in the lung parenchyma.

Spectrum of Flurodeoxyglucose Positron Emission Tomography/Computerized Tomography Findings in Tumors and Tumor-Like Conditions of the Musculoskeletal System.

Bone and soft-tissue tumors display a wide range of metabolic activity on flurodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) imaging due to their varying histopathological features. Several benign tumors show high FDG uptake similar to that seen in malignant lesions and their metabolic characteristics can overlap. Certain benign tumors can potentially undergo malignant transformation and FDG PET/CT can play an important role in detecting malignant change. The intensity of metabolic activity on FDG PET/CT correlates with histological grade of malignant tumors and also acts as a valuable prognostic factor. FDG PET/CT plays an important role in the staging work up of bone and soft-tissue malignancies. It has been found to be superior to conventional imaging techniques primarily for detecting distant metastatic disease. Because of its ability to detect metabolic changes, FDG PET/CT is a very useful in assessing response to treatment. Metabolic response seen on FDG PET is a powerful surrogate marker of histopathological response to chemotherapy. The purpose of this article is to study the variable patterns of FDG uptake in tumors of the musculoskeletal system, describe the clinical utility of FDG PET/CT in predicting malignant change in benign tumors and discuss its role in staging, response assessment, and prognostication of malignant lesions.

Myeloid Sarcoma of the Prostatic Tissue Diagnosed on 18F-FDG PET/CT in Treated Case of Acute Myeloid Leukemia.

Myeloid sarcoma is a rare extramedullary manifestation of acute myeloid leukemia (AML) that often presents during remission or disease relapse. The most common site of relapse being, however, many rare sites has been reported in the existing literature. We are herewith presenting the case of a 27-year-old patient of AML who showed an unusual site of relapse on fluorodeoxyglucose positron emission tomography/computed tomography scan.

Pelvic Venous Thromboembolism Leading to Pulmonary Embolism in a Case of Chondroblastic Osteosarcoma Detected on FDG PET/CT.

Chondroblastic osteosarcoma is an uncommon subtype of osteosarcoma, constituting about 25% of all osteosarcoma cases. It has shown high propensity for developing tumor thrombi and thromboembolism, with poor overall survival rate. Differentiation between tumor thrombus and bland thrombus is an important factor in making treatment decisions. 18 F fluorodeoxyglucose positron emission tomography/computed tomography plays a very important role in detecting and differentiating bland thrombus from tumor thrombus.

Brain FET PET tumor-to-white mater ratio to differentiate recurrence from post-treatment changes in high-grade gliomas.

BACKGROUND AND PURPOSE: Highergrade glial neoplasms undergo standard treatment with surgery, radiotherapy, and alkylating agents. There is often a clinical/neuroimaging dilemma in the post-treatment setting to differentiate disease recurrence from treatment-related changes. FET (fluoro-ethyl-tyrosine) PET has emerged as a molecular imaging modality for cases where MR imaging is inconclusive. This study aims to develop a cutoff on FET PET for differentiating true recurrence from post-treatment changes. METHODS: We retrospectively analyzed72 patientswith post-treatment grade 3 or 4 brain gliomas. Five to six mCi of 18 F-FET was injected and static imaging of the brain was performed at 20 min. A tumor-to-white matter (T/Wm) ratio was used as semiquantitative parameter. A T/Wm cutoff of 2.5 was used for image interpretation. Imaging findings were confirmed by either histopathologic diagnosis in a multidisciplinary joint clinic or based on follow-up of clinical and neuroimaging findings. RESULTS: Forty-one of 72 patients (57%) showed recurrent disease on FET PET. Thirty-five of them were confirmed to have tumor recurrence; six patients showed post-treatment changes. Thirty-one of 72 patients (43%) showed post-treatment changes on FET PET; 27 were confirmed as post-treatment change and four patients had tumor recurrence on subsequent MR imaging. An optimum T/Wm cutoff of 2.65 was derived based on receiver operating characteristic analysis with a sensitivity of 80% and specificity of 87.5%. CONCLUSION: Static FET PET can be used as problem-solving imaging modality with a T/Wm cutoff of 2.65 to differentiate late recurrence from post-treatment changes in grade 3 or 4 brain gliomas with equivocal MR features.

Unusual Variant of Breast Cancer Presenting With Pituitary Symptoms Detected on 68Ga-DOTATATE PET/CT.

ABSTRACT: Carcinoma of breast with neuroendocrine differentiation is an extremely rare entity, especially in male population. Although the "garden variety" of male breast cancers is often metastatic at presentation, with an aggressive course, there is hardly any literature about neuroendocrine variants. We report a case of a 57-year-old man who had pituitary symptoms, which on 68Ga-DOTANOC PET/CT imaging turned out to be a metastatic lesion, with somatostatin expressing primary in breast and other sites, with histopathological confirmation of neuroendocrine differentiation in breast cancer.