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.

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.

Dose estimation in patients from different protocols of 18F-FDG PET/CT studies and analysis of optimization strategies.

This study aimed to evaluate the dose in different protocols of 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (PET/CT) procedure. The retrospective study involves 207 patients with confirmed malignancies who underwent PET/CT. Effective dose (E) from PET was estimated based on injected activity and dose coefficient as per International Commission on Radiation Protection (ICRP) 128. Estimation of E from CT was done utilizing the dose length product (DLP) method and conversion factors as per ICRP 102. There was a significant statistical difference observed in E between different PET/CT protocols (P < .001). E of PET in the whole body (WB) was found to be 4.9 ± 0.9 mSv, whereas mean volume computed tomography dose indexvol, DLP, and E of CT in WB were 7.0 ± 0.2 mGy, 674.3 ± 80.7 mGy.cm, and 10.1 ± 1.2 mSv, respectively. No linear correlation was seen between the size-specific dose estimate and E of CT (r = -0.003; P = .978). The total mean E in WB PET/CT was 17.0 ± 1.7 mSv. CT dose was contributing more than PET dose in all protocols except brain PET/CT. Optimization strategies can be evaluated only if monitored periodically.

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.

Can 18 F FDG PET/CT metabolic parameters be used to noninvasively differentiate between different histopathological subtypes and Fuhrman grades of renal cell cancer?

AIM: To evaluate relationship between metabolic PET metabolic parameters and size of the primary tumor, various histopathological subtypes of renal cell carcinoma (RCC) and Fuhrman grade of the tumors. MATERIAL AND METHODS: Retrospective analysis of 93 biopsy-proven RCC patients who underwent pretreatment flourine 18 flourodeoxyglucose PET/computed tomography ( 18 F FDG PET/CT) was performed. Quantitative PET parameters, size of the primary tumor, histopathological subtypes and Fuhrman grades of the tumor were extracted. We tried to assess if there was any significant difference in the metabolic patterns of various histopathological subtypes of RCCs, Fuhrman grade of the tumors and size of the primary tumor. RESULTS: A significant correlation was noted between the size of primary tumor and maximum standardized uptake value (SUV max ), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) ( P  < 0.01, P  < 0.001 and P  < 0.001, respectively). SUV max values correlated significantly with the histopathological subtype ( P  < 0.001). Further sub-analyses was also done by segregating the patients into Low grade (Fuhrman grade 1 and 2) vs. High grade (Fuhrman grade 3 and 4). SUV max , MTV and TLG were significantly different between high grade vs. low grade tumors. ROC analysis yielded cut off values for SUV max , MTV and TLG to differentiate between high grade from low grade tumors. CONCLUSION: FDG PET/CT with the use of metabolic PET parameters can differentiate between different histopathological subtypes of RCC. Incorporation of metabolic parameters into clinical practice can potentially noninvasively identify patients with low-grade vs. high-grade RCC.

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.

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.

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.

Analysis of image quality by regulating beta function of BSREM reconstruction algorithm and comparison with conventional reconstructions in carcinoma breast studies of PET CT with BGO detector.

BACKGROUND: The study aimed to evaluate the beta penalization factor of the BSREM reconstruction algorithm on a five-ring BGO-based PET CT system and compared it with conventional reconstructions. METHODS: Retrospective study involves 30 breast cancer patient data of 18F-fluorodeoxyglucose ( 18 F-FDG) PET CT for reconstruction with OSEM, OSEM + PSF, and BSREM under variable ß factors ranging from 200 to 600 in the steps of 50. Liver noise, lesion SUVmax, SBR, and SNR for each reconstruction were calculated. Quantitative parameters of each beta factor of BSREM were compared with OSEM and OSEM + PSF, using the Wilcoxon sign rank test with Bonferroni correction, a value of P < 0.002 was considered statistically significant. Visual scoring by two readers was also evaluated. RESULTS: Thirty lesions of mean size 1.91 ± 0.58 cm range (0.7-3.6 cm) were identified. Liver noise and SBR were reduced, whereas SNR was increased with an increasing ß value of BSREM. In comparison with OSEM, liver noise was not significantly different from ß200 and ß250. SNR of OSEM was significantly lower than any other ß factors and SBR of ß factor less than 500 was significantly higher than OSEM. In comparison with OSEM + PSF, liver noise was not significantly different from ß400 and ß350-500 do not show a significant difference in SNR and SBR compared with OSEM + PSF. ß350 scored highest under visual scoring with a moderate agreement. CONCLUSION: The study quantitatively indicates the optimum beta range of ß250-450 and the qualitative evaluation indicates that ß350 is an optimum beta factor of BSREM in breast cancer cases for 18 F-FDG WB-PET CT.

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.

Evaluation of post-chemotherapy residual seminomatous masses by 18F-fluorodeoxyglucose PET/CT using tumor-to-liver ratio - conundrum or solution?

OBJECTIVE: Assessment of diagnostic accuracy of FDG-PET/CT in the detection of viable disease in post-chemotherapy seminomatous residual masses using visual interpretation, SUVmax, and T/L ratio. METHODS: This is a retrospective study assessing the post-chemotherapy seminomatous residual masses of size >3 cm. The PET/CT scan findings were interpreted visually for presence of residual disease which were validated from histopathology reports or imaging follow-up for a maximum of 3 years. SUVmax and T/L ratios were also determined for all the residual lesions. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value NPV were calculated and compared for all three parameters along with ROC analysis to obtain an optimal cutoff value for SUVmax and T/L ratio, respectively. RESULTS: Sample size was 49. Out of these 49 patients, 8 had validation of PET results with histopathology. Rest was validated with imaging follow-up. FDG-PET was positive in 30 patients and negative in 19 patients by visual interpretation. The sensitivity, specificity, PPV, and NPV by this method were 100%, 62.5%, 73%, and 100%, respectively. The SUVmax and T/L ratios were also calculated for these lesions. The cutoff for these two variables was 4.56 and 1.21, respectively. The sensitivity, specificity, PPV, and NPV at these cutoffs were 76%, 87.5%, 86%, 77.7%, and 92%, 87.5%, 88%, 91%, respectively. CONCLUSION: FDG-PET has a favorable diagnostic value in predicting viable disease in post-chemotherapy seminomatous residual masses and using T/L ratio cutoff of 1.21 will increase the specificity of the test.

Intracranial disease in pediatric Hodgkin lymphoma-case report and review of literature.

Central nervous system (CNS) involvement in Hodgkin lymphoma (HL) is an extremely rare presentation with dismal outcomes according to reported literature. An 8-year-old girl presented to us with complaints of on-off fever, right cervical swelling and bilateral ptosis. Positron emission tomography (PET) showed intracranial extra-axial soft tissue masses in right infero-lateral temporal lobe, sella and bilateral parasellar region along with cervical, mediastinal, axillary, abdominal and inguino-pelvic nodes, liver lesions and extensive marrow lesions involving the axial and appendicular skeleton. Histopathology of the cervical lymph node revealed a diagnosis of classical Hodgkin lymphoma. Child received 2 cycles of OEPA and 4 cycles of COPP followed by radiotherapy to bulky cervical lymph nodes and intracranial lesion. The child has been disease-free for 44 months with no neurological sequalae. Intracranial spread is rare in Hodgkin lymphoma and is associated with inferior outcomes. Due to its rarity, there are no specific treatment guidelines for this entity. The choice of ideal chemotherapeutic agents and role of whole-brain radiotherapy needs further evaluation.

18 F-FDG PET/CT Appearance of Radiation-Induced Delayed Transverse Myelitis.

ABSTRACT: Delayed-onset radiation-induced myelitis is a rare but serious complication of radiation exposure to the spinal cord. In this report, we describe the 18 F-FDG PET/CT findings of radiation-induced myelitis in a patient with carcinoma of buccal mucosa treated with external beam radiotherapy.

Comparison of 68 Ga-FAPI PET and 18 F-FDG PET Findings in a Patient With Bilateral Breast Cancer of 2 Different Histopathologies.

ABSTRACT: We present the findings of 18 F-FDG PET and 68 Ga-fibroblast activation protein PET scans done in a case of bilateral breast carcinoma with 2 different histopathology, left breast tubulolobular carcinoma and right breast invasive breast carcinoma of no special type.

Congenital Melanocytic Nevi Syndrome With Leptomeningeal Melanoma.

ABSTRACT: The incidence of congenital melanocytic nevi (CMNs) is 1% to 6% for small- to intermediate-size nevi to 1 in 500,000 for giant size nevi. Large and satellite CMNs are known to be associated with neurocutaneous melanosis and central nervous system malformations such as Dandy-Walker malformation, defects of the vertebra-skull, and intraspinal lipomas. We hereby present a case of CMN syndrome in an 18-year-old girl with leptomeningeal melanoma, evaluated with MRI, adequately staged, and screened with FDG PET.

Unusual Presentation of Helicobacter pylori Infection as PSMA-Avid Gastric Mass.

ABSTRACT: 68 Ga-PSMA PET/CT is one of the most common imaging uses for prostate cancer imaging. Although initially thought to be specific for prostate cancer, there are many evidences that are coming of its concentration in many other neoplastic and nonneoplastic pathologies. Helicobacter pylori is the most common bacteria causing gastric inflammation and usually presents with gastroduodenal ulcer. Here we present one unusual case of benign gastric mass formation caused by H. pylori infection with PSMA concentration.

Bone metastases in prostate cancer - Gallium-68-labeled prostate-specific membrane antigen or Fluorine 18 sodium fluoride PET/computed tomography - the better tracer?

OBJECTIVE: The objective was to assess the roles of 68Ga-PSMA PET/CT and 18F-NaF PET/CT in evaluation of skeletal metastatic lesions in prostate cancer. METHODS: Two hundred consecutive prostate cancer patients who had undergone 68Ga-PSMA PET/CT and 18F-NaF PET/CT at baseline evaluation (n = 80) and following suspected recurrence or disease progression (restaging) (n = 120) were analyzed retrospectively. RESULTS: PSMA and NAF scans were positive for skeletal metastatic lesions in 67% (134 patients) and negative in 33% (66 patients). The scans were concordant in 80% (160 patients: 66 negative and 94 positive) and discordant in 20% (40 patients). Among 40 discordant results, 14 were baseline and 26 were restaging studies. PSMA detected more number of lesions in 11 (nine baseline and two restaging). These were true positive marrow or lytic metastatic lesions. NaF revealed more number of lesions in 29 (5 initial and 24 restaging). These were false positive on follow-up imaging. No statistical difference (P value = 0.7 by McNemar test) between the two scans for identifying absence or presence of at least one skeletal lesion was noted at baseline staging. CONCLUSION: Though, both 18F-NaF and 68Ga-PSMA are excellent tracers for evaluation of skeletal metastases in prostate cancer, there is a distinct advantage of 68Ga-PSMA PET/CT due to detection of additional skeletal lesions and absence of false positive lesions. In addition, absence of PSMA avidity in healed metastases in the restaging setting opens up new avenue for assessment of response of skeletal metastases.

Impact of FDG PET/CT Scan in Changing Management of Well-Differentiated Neuroendocrine Tumors With Ki67 Index Less Than or Equal to 5.

OBJECTIVES: This study aimed to see the impact of FDG PET/CT with somatostatin receptor PET (SSTR PET) in directing the treatment plan in lower-grade well-differentiated neuroendocrine tumors (NETs) with Ki67 index ≤5%. METHODS: Sixty-three NET cases with Ki67 index ≤5% with both FDG PET and SSTR PET ( 68 Ga-DOTANOC PET) were included for this retrospective observational study. FDG PET findings were classified into positive, weakly positive, and negative based on a visual scale. Clinical factors considered while referring for FDG PET scan were audited from electronic medical records. The addition of chemotherapy was considered as FDG-directed change in treatment. RESULTS: Sixty patients showed intense SSTR expression in the primary and metastatic sites (if present). Three patients showed no evidence of SSTR expression, in whom the scans were done after resection of the primary tumor. The FDG PET was positive in 25 (39.6%), weakly positive in 11 (17.4%), and negative in 27 (42.8%). Specific clinical reason for doing FDG PET was found in 34 patients, and in the remaining 29, there was no justification or specific indication for doing the FDG study; 73.5% of patients from the former group was either FDG positive or weakly positive, and 26.5% were negative; in the other group, 62.1% were FDG-negative, and 37.9% were positive ( P = 0.004). Treatment-naive patients with symptom duration of ≤5 months were associated with more FDG positivity than patients with >5 months' symptom duration ( P = 0.006). FDG PET/CT led to change in management in 17.4% of all the patients, 9.6% of grade 1, and 25% of grade 2 patients. CONCLUSIONS: In lower-grade NET, FDG positivity was seen in a sizable number of the cases, and this led to change in management in 17.4% of the cases. Specific clinical features could be utilized to successfully discriminate between FDG-avid and non-FDG-avid disease in lower-grade NETs, and this had impact in management change as well.

Rare Presentation of Radiation-induced Sarcoma Detected on F-18 FDG Positron Emission Tomography/Computed Tomography in a Treated Case of Giant Cell Tumor.

Giant cell tumors (GCTs) are benign bone lesions which are treated with curettage and bone grafting. Infrequently, GCTs show local site recurrences which are then treated with either surgical excision or radiation therapy. Radiation-induced sarcoma is rarely seen as a late complication of radiation therapy which needs to be differentiated from recurrent GCT. We report one such rare case of radiation-induced sarcoma detected on Flourine-18 fluorodeoxyglucose (18F FDG) positron emission tomography/computed tomography in a 40-year-old male who was treated with radiation therapy for recurrent GCT 9 years ago.