Residual Thyroid Tissue on Postoperative Diagnostic 131 I Radioactive Whole-Body Scan After Surgery in Differentiated Thyroid Cancer: A Tertiary Referral Centre Experience.

Residual thyroid tissue after total thyroidectomy in differentiated thyroid cancers is considered an independent risk factor for recurrence. Guidelines recommend following up patients after surgery with thyroglobulin (Tg), neck ultrasonography, and occasionally whole-body radioactive scan. However, the results of serum thyroglobulin and whole-body radioiodine scan are often discordant. The present study was undertaken to determine the levels of serum-stimulated thyroglobulin to complement the findings of residual thyroid tissue in the radioactive whole-body scan. One hundred twenty-six patients had undergone a radioiodine (131 I) whole-body scan (WBS) during the study duration, and 121 were available for analysis. The thyroglobulin level (measured by the CLIA method) was recorded at the time of these scans. The data was analysed to determine the level of stimulated thyroglobulin correlating with residual thyroid tissue, locoregional, and distant metastasis as assessed by WBS. The presence of residual thyroid tissue was noted in an overwhelmingly high 94% of cases. Twenty-four of the 28 patients with stimulated Tg < 2 ng/dl had residual thyroid tissue on a WBS. The discordancy rate (positive moderate - large WBS and negative serum thyroglobulin) of 64.28% was seen. Using ROC the serum thyroglobulin cut-offs levels for the loco-regional disease were found to be 27.705 ng/dl and 94.770 ng/dl for distant metastasis. The results highlight the fact that serum Tg levels cannot be used as an accurate predictor of the extent of the remnant thyroid tissue. Irrespective of the quality of surgery, which was analysed based on the centre and surgical specialty, over 90% of cases had residual thyroid tissue on WBS. The use of only stimulated Tg levels for follow-up may be inaccurate. Serum Tg is a useful test along with radioactive whole-body scans to distinguish local disease, loco-regional disease, and distant metastasis.

Role of Positron Emission Tomography/Computed Tomography in Preoperative Assessment of Carcinoma Endometrium-a Retrospective Analysis.

PET/CT has made significant inroads into routine oncological practice in recent times. In our study, we aim to determine its value in preoperative assessment of endometrial carcinoma. A retrospective study between January 2011 and March 2016 was conducted; we included all cases of carcinoma endometrium with a preoperative PET/CT scan. PET/CT images were analyzed and correlated with histological findings after surgical staging. A total of 46 cases were analyzed, mean age was 59.8 years, BMI 30.8 kg/m2, and most common histology endometrioid type (69.5%). We correlated PET/CT findings with histopathology as reference standard. PET/CT had a sensitivity of 40%, moderate specificity (75%) and accuracy (71.7%), good NPV (91.2%), but poor PPV (16.7%) for lymph node involvement. A total of 10 (21.7%) cases were detected to have distant metabolically active lesions on PET/CT, seven out of these were positive for malignancy. And 90% of them were either non-endometrioid type or grade two and higher. We found that SUV of primary tumor was significantly higher in patients with deep myometrial invasion (p = 0.018), and high-risk histological type of tumor (p = 0.022), though not statistically significant when lymph nodal involvement (p = 0.9), cervical involvement (p = 0.56), or histological grade (p = 0.84) were considered. Sensitivity and specificity of PET/CT in staging endometrial cancer is not high enough to reliably tailor lymphadenectomy. Although SUV of the primary tumor was significantly higher in patients with deep myometrial invasion and high-risk histological type, it's usefulness in classifying patients into predefined risk groups seems to be limited. However, it is useful in detecting distant metastasis especially in high-grade and non-endometrioid type of tumors. Thus, implementation of PET/CT as a surrogate for surgical staging of endometrial cancer remains enigmatic and is open to further research.

Utility of EBUS-TBNA in PET-positive mediastinal lymph nodes in subjects with extra-thoracic malignancy.

BACKGROUND/AIM: Patients with primary extra-thoracic malignancy (ETM) often have hyper-metabolic mediastinal lymph nodes (HM-MLN) in the PET-scan done for initial staging or post treatment follow-up. There is scant data on the etiology of HM-MLN in such patients, which can also be due to non-malignant causes. We used endobronchial ultrasound (EBUS) guided sampling to determine the etiology of HM-MLN in patients with ETM and study the relationship between PET-SUV values and a diagnosis of malignancy in this population. MATERIALS AND METHODS: 65 consecutive patients, from March 2013 to March 2017 with either known ETM for primary staging or post-treatment follow-up, with PET CT showing HM-MLN (SUV > 2.5) were included in the study. RESULTS: 65 patients with ETM had EBUS-TBNA for HM-MLN. 20/65 (30.7%) were malignant, 45/65 (69.23%) were benign MLN. In patients with benign etiology of HM-MLN, 6/45 (13.3%) had necrotising granulomatous, 24/45 (53.3%) had non- necrotising granulomatous MLN and 15/45 (33.3%) had reactive MLN. We found discordance (i.e. primary ETM responded to treatment and a new HM-MLN was detected) in 21/65 (32.3%) patients with PET-CT done for initial ETM staging, and 44/65 (67.7%) with a post-treatment PET-CT. showed. Correlating SUV with diagnoses, the SUV values in EBUS-proven malignant MLN were 8.9 ± 4.1, while they were 10.2 ± 5.57 in benign MLN. There was no statistically significant difference between the SUV of benign and malignant MLNs. CONCLUSION: This study shows a significant incidence of EBUS-TBNA proven benign diagnoses 45/65 (69.2%) in 'SUV-deemed-malignant MLN' and a poor relationship between high SUV and malignant MLN, in patients with known ETM. The ETM related HM-MLN have a significant chance of being benign, and a tissue diagnosis is imperative as it impacts on the treatment plan and prognosis.

Small-Sized Thyroid Cancers-a Single Institutional Experience in India.

The incidence of small differentiated thyroid carcinomas is increasing worldwide in the recent years, especially tumours of size less than 2 cm in diameter. In this study, we have analysed the patterns of behaviour of small-sized thyroid carcinomas (<2 cm, T1 tumours) in comparison with large-sized thyroid carcinomas. This is a retrospectively analysed data of patients with thyroid carcinoma. The following parameters were analysed: distribution with regard to age, sex and the presence of metastasis based on radioiodine scan. The following histopathological details were collected: maximal tumour diameter, extrathyroidal extension and lymphovascular invasion. Out of 152 patients, 39 patients were excluded due to the non-availability of complete details. Among the 113 patients of thyroid carcinomas, 43 patients (28%) were presented with small-sized tumours (measuring less than 2 cm). In small-sized thyroid tumours, 21.6% showed extrathyroidal extension. 2.7% of the small-sized thyroid carcinomas showed perineural invasion as compared to 6.3% of the large-sized thyroid carcinomas. Twenty percent of the small-sized thyroid carcinomas showed lymphovascular emboli. 51.2% of the small-sized thyroid carcinomas were presented with nodal metastasis as compared to 40% of the large-sized thyroid carcinomas. 57.5% of the small-sized thyroid carcinomas showed extracapsular extension as compared to 57.8% of the large-sized thyroid carcinomas. Despite small size, thyroid carcinomas have properties to behave aggressively as comparable to large-sized thyroid carcinomas. Taking the above facts into account, the small thyroid cancers should be treated with considerable caution as large thyroid cancers, especially since we have limited tools to predict the preoperative poor prognostic factors.

Utility of Gallium-68 DOTANOC PET/CT in the localization of Tumour-induced osteomalacia.

BACKGROUND: Tumour-induced osteomalacia (TIO) is a rare disorder characterized by hypophosphataemic osteomalacia caused by small mesenchymal tumours secreting fibroblast growth factor 23 (FGF 23). The most difficult part in the management of these patients is the localization of tumours causing TIO. OBJECTIVE: We describe the utility of Gallium (Ga)-68 DOTANOC PET/CT in the localization of tumours causing TIO. PATIENTS AND METHODS: The study was conducted in a single tertiary referral university teaching hospital in India. Ten patients with TIO who underwent Ga-68 DOTANOC PET/CT from the time period 2009 to 2014 were included in this study. Their detailed clinical history, biochemical parameters, imaging modalities, surgical interventions, histopathology and outcomes were reviewed. RESULTS: Ga-68 DOTANOC PET/CT could correctly localize the tumours in TIO in 9 of the 10 cases in which it was performed. Complete resection of the tumour led to full clinical recovery in six of the ten patients; two patients who had partial resection and one patient who underwent radiofrequency ablation showed partial remission. One patient in whom Ga-68 DOTANOC PET/CT was positive in vertebral body with a low standardized uptake value (SUV) did not show up the tumour on surgery. CONCLUSIONS: We conclude that Ga-68 DOTANOC PET/CT can be used as the first imaging modality in patients diagnosed with TIO. The extremely good outcome following the resection of these small otherwise undiagnosed tumours far outweighs its cost even in resource limited settings.

Multicenter Reproducibility of 18F-Fluciclatide PET Imaging in Subjects with Solid Tumors.

UNLABELLED: Integrins are upregulated on both tumor cells and associated vasculature, where they play an important role in angiogenesis and metastasis. Fluciclatide is an arginine-glycine-aspartic acid peptide with high affinity for αvß3/αvß5 integrin, which can be radiolabeled for PET imaging of angiogenesis. Thus, (18)F-fluciclatide is a potential biomarker of therapeutic response to antiangiogenic inhibitors. The aim of this study was to evaluate the reproducibility of (18)F-fluciclatide in multiple solid-tumor types. METHODS: Thirty-nine patients underwent PET/CT scanning at 40, 65, and 90 min after injection of (18)F-fluciclatide (maximum, 370 MBq) on 2 separate days (2-9 d apart). Patients did not receive any therapy between PET/CT scans. (18)F-fluciclatide images were reported and quantitative measures of uptake were extracted using the PERCIST methodology. Intrasubject reproducibility of PET uptake in all measurable lesions was evaluated by calculating relative differences in SUV between PET scans for each lesion during the 2 imaging sessions. RESULTS: Thirty-nine measurable lesions were detected in 26 patients. Lesion uptake correlated strongly across imaging sessions (r = 0.92, P < 0.05, at 40 min; r = 0.94, P < 0.05, at 65 min; r = 0.94, P < 0.05, at 90 min) with a mean relative difference and SD of the relative difference of 0.006 ± 0.18 at 40 min, 0.003 ± 0.19 at 65 min, and 0.025 ± 0.20 at 90 min. This reflects 95% limits of repeatability of 35%-39% for the difference between the 2 SUV measurements or a variability of 18%-20% in agreement from that observed in well-calibrated multicenter (18)F-FDG studies. CONCLUSION: The test-retest reproducibility of (18)F-fluciclatide across multiple tumor types has been measured and shown to be acceptable. This is an important step in the development of this in vivo biomarker to identify and quantify response to antiangiogenic therapy in cancer patients.

Re-irradiation with hypo-fractionated stereotactic robotic radiotherapy for salvage in adult patients with brainstem glioma.

PURPOSE: Brainstem glioma (BSG) is often treated with definitive irradiation. However, subsequent progression and death occur as a rule rather than the exception, after varying periods of control. The outlook of patients with post-irradiation progression is dismal, and most of these patients are treated with supportive care alone. Despite the obvious risks with an area as critical as the brainstem, it is a possibility to encounter situations wherein the patients (themselves or their associates) ask for re-irradiation, with the hope of a few extra months of life. The risk of radiation-induced brainstem toxicity may be justifiable under the strict assumption that the patients stand a chance of benefiting from re-irradiation but still may not live long enough to manifest brainstem toxicity. METHODS: Five adult BSG patients were treated with re-irradiation using robotic-arm stereotactic radiation therapy (SRT) between September 2009 and July 2012, primarily at the request of the concerned patient parties. Re-irradiation doses ranged from 16 to 25 Gray (Gy) delivered by robotic arm stereotactic irradiation in 2-5 fractions. RESULTS: Four out of five patients enjoyed a prolongation of survival in the order of months (three, five, six, and 14 months), which was very significant given that all patients had severe neurological compromise and poor performance status prior to re-irradiation. One patient has survived 36 months after re-irradiation and thus has lived long enough to manifest late radiation-induced brainstem toxicity. CONCLUSION: Despite the obvious risks of brainstem toxicity associated with the use of re-irradiation for BSG, the use of fractionated stereotactic re-irradiation seems to offers prospects of additional periods of local control and augments duration of life.

Preparation of patient doses of (177)Lu-DOTA-TATE using indigenously produced (177)Lu: the Indian experience.

PURPOSE: (177)Lu (T(1/2) = 6.73 days, E(ß(max)) = 0.497 MeV, E(γ) = 113 KeV [6.4%] and 208 KeV [11%])-labeled DOTA-TATE, a somatostatin analog, is presently being considered a promising agent for the treatment of patients suffering from inoperable neuroendocrine tumors, which overexpress somatostatin receptors. The objective of the present work was to develop an optimized protocol for the preparation of therapeutic dose of (177)Lu-DOTA-TATE with as high as achievable specific activity at the time of its administration, taking into account the variable specific activity of (177)Lu available during the preparation of the agent. METHODS: (177)Lu labeling of DOTA-TATE was carried out using a precalculated amount of DOTA-TATE based on the available specific activity of (177)Lu at the time of preparation, keeping a minimum molar ratio of [DOTA-TATE]:[Lu] = 4:1, so that (177)Lu-DOTA-TATE could be obtained with highest possible specific activity without compromising its radiochemical purity and stability. RESULTS: One hundred (100) batches of (177)Lu-DOTA-TATE were prepared following this protocol till date at five different nuclear medicine centers of India, with a radiochemical purity of 98.25% ± 1.1% and specific activity of 32.74-65.49 GBq/µmol (885-1770 mCi/µmol). Till date, 250 patient doses of (177)Lu-DOTA-TATE have been dispensed and administered in 150 patients suffering from various types of neuroendocrine-originated tumors. CONCLUSIONS: The developed method ensures that patient doses of (177)Lu-DOTA-TATE could be prepared with highest possible specific activity depending upon the available specific activity of (177)Lu at the hospital radio-pharmacy.

Technical note: Image guided internal fiducial placement for stereotactic radiosurgery (CyberKnife).

Internal gold fiducials are necessary for tracking the translational and rotational movements of target lesions during stereotactic radiosurgery. The fiducials are generally placed under image guidance in and around the lesions by interventional radiologists. Specific challenges are encountered during the procedure. This article discusses the basic principles and techniques as well as the specific complications.

PET/CT-guided percutaneous biopsy of isolated intramuscular metastases from postcricoid cancer.

(18)F-FDG PET/CT has made it possible to identify many unsuspected lesions such as isolated intramuscular metastases because of its ability to detect abnormal metabolic activity in an early stage even without clinical symptoms or morphologic changes. We need to modify our routine techniques for performing biopsies of such lesions because they may not be visualized on morphologic imaging. We describe a technique in which fused PET/CT is used to guide the percutaneous biopsy needle for sampling isolated intramuscular metastatic lesions in a patient whose intramuscular metastases were identified only on PET/CT, not on CT or ultrasound, and were clinically occult.

Marchiafava-Bignami disease: Two cases with magnetic resonance imaging and positron emission tomography scan findings.

We report two patients with Marchiafava-Bignami disease (MBD). A 38-year-old male with chronic alcohol abuse developed acute onset cerebellar ataxia and altered sensorium. He was diagnosed to have acute form (Type II) of MBD. Magnetic resonance imaging (MRI) showed extensive lesions involving the corpus callosum in its entire extent and also bilateral corona radiata and centrum semiovale. Corpus callosum had heterogeneous signal changes with ring enhancement. Positron emission tomography scan demonstrated reduced cerebral glucose metabolism diffusely over both the cerebral hemispheres. The second patient was 55-year-old male with chronic alcohol intake developed acute onset vomiting followed by behavioral abnormalities and altered sensorium. MRI showed diffuse lesion involving entire corpus callosum with suggestion of necrosis. Both the patients subsequently recovered, the first patient is back to his previous occupation and the second patient could be rehabilitated with some lighter work in his previous work place. Functional brain imaging may help to understand the pathogenesis of acute MBD and possibly the behavioral manifestations.