Clinical Trial Protocol for PRIMARY2: A Multicentre, Phase 3, Randomised Controlled Trial Investigating the Additive Diagnostic Value of [68Ga]Ga-PSMA-11 Positron Emission Tomography/Computed Tomography in Men with Negative or Equivocal Multiparametric Magnetic Resonance Imaging for the Diagnosis of Clinically Significant Prostate Cancer

BACKGROUND

Multiparametric magnetic resonance imaging (mpMRI) has an established role for the diagnosis of clinically significant prostate cancer (sPCa). The PRIMARY trial demonstrated that [68Ga]Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) was associated with a significant improvement in sensitivity and negative predictive value for sPCa detection.

OBJECTIVE

To demonstrate that addition of prostate-specific membrane antigen (PSMA) radioligand PET/CT will enable some men to avoid transperineal prostate biopsy without missing sPCa, and will facilitate biopsy targeting of PSMA-avid sites.

DESIGN, SETTING, AND PARTICIPANTS

This multicentre, two-arm, phase 3, randomised controlled trial will recruit 660 participants scheduled to undergo biopsy. Eligible participants will have clinical suspicion of sPCa with a Prostate Imaging-Reporting and Data System (PI-RADS) score of 2 and red flags, or a PI-RADS score of 3 on mpMRI (PI-RADS v2). Participants will be randomised at a 1:1 ratio in permuted blocks stratified by centre. The trial is registered on ClinicalTrials.gov as NCT05154162.

INTERVENTION

In the experimental arm, participants will undergo pelvic PSMA PET/CT. Local and central reviewers will interpret scans independently using the PRIMARY score. Participants with a positive result will undergo targeted transperineal prostate biopsies, whereas those with a negative result will undergo prostate-specific antigen monitoring alone. In the control arm, all participants undergo template transperineal prostate biopsies. Participants will be followed for subsequent clinical care for up to 2 yr after randomisation.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

sPCa is defined as Gleason score 3 + 4 (≥10%) = 7 disease (grade group 2) or higher on transperineal prostate biopsy. Avoidance of transperineal prostate biopsy will be measured at 6 mo from randomisation. The primary endpoints will be analysed on an intention-to-treat basis.

CONCLUSIONS

Patient enrolment began in March 2022, with recruitment expected to take 36 mo.

PATIENT SUMMARY

For patients with suspected prostate cancer who have nonsuspicious or unclear MRI (magnetic resonance imaging) scan findings, a different type of scan (called PSMA PET/CT; prostate-specific membrane antigen positron emission tomography/computed tomography) may identify men who could avoid an invasive prostate biopsy. This type of scan could also help urologists in better targeting of samples from suspicious lesions during prostate biopsies.

Comparison of quantitative whole body PET parameters on [68Ga]Ga-PSMA-11 PET/CT using ordered Subset Expectation Maximization (OSEM) vs. bayesian penalized likelihood (BPL) reconstruction algorithms in men with metastatic castration-resistant prostate cancer

BACKGROUND

PSMA PET/CT is a predictive and prognostic biomarker for determining response to [177Lu]Lu-PSMA-617 in patients with metastatic castration resistant prostate cancer (mCRPC). Thresholds defined to date may not be generalizable to newer image reconstruction algorithms. Bayesian penalized likelihood (BPL) reconstruction algorithm is a novel reconstruction algorithm that may improve contrast whilst preventing introduction of image noise. The aim of this study is to compare the quantitative parameters obtained using BPL and the Ordered Subset Expectation Maximization (OSEM) reconstruction algorithms.

METHODS

Fifty consecutive patients with mCRPC who underwent [68Ga]Ga-PSMA-11 PET/CT using OSEM reconstruction to assess suitability for [177Lu]Lu-PSMA-617 therapy were selected. BPL algorithm was then used retrospectively to reconstruct the same PET raw data. Quantitative and volumetric measurements such as tumour standardised uptake value (SUV)max, SUVmean and Molecular Tumour Volume (MTV-PSMA) were calculated on both reconstruction methods. Results were compared (Bland-Altman, Pearson correlation coefficient) including subgroups with low and high-volume disease burdens (MTV-PSMA cut-off 40 mL).

RESULTS

The SUVmax and SUVmean were higher, and MTV-PSMA was lower in the BPL reconstructed images compared to the OSEM group, with a mean difference of 8.4 (17.5%), 0.7 (8.2%) and - 21.5 mL (-3.4%), respectively. There was a strong correlation between the calculated SUVmax, SUVmean, and MTV-PSMA values in the OSEM and BPL reconstructed images (Pearson r values of 0.98, 0.99, and 1.0, respectively). No patients were reclassified from low to high volume disease or vice versa when switching from OSEM to BPL reconstruction.

CONCLUSIONS

[68Ga]Ga-PSMA-11 PET/CT quantitative and volumetric parameters produced by BPL and OSEM reconstruction methods are strongly correlated. Differences are proportional and small for SUVmean, which is used as a predictive biomarker. Our study suggests that both reconstruction methods are acceptable without clinical impact on quantitative or volumetric findings. For longitudinal comparison, committing to the same reconstruction method would be preferred to ensure consistency.

Development of a Visually Calculated SUVmean (HIT Score) on Screening PSMA PET/CT to Predict Treatment Response to 177Lu-PSMA Therapy: Comparison with Quantitative SUVmean and Patient Outcomes

177Lu-PSMA therapy is an effective treatment in patients with metastatic castration-resistant prostate cancer. SUVmean is a valuable screening biomarker to assess the suitability for 177Lu-PSMA therapy but requires quantitative software. This study aims to develop a simple, clinically applicable prostate-specific membrane antigen PET/CT score that encompasses the elements of SUVmean without requiring additional quantification. Methods: Datasets from ethics-approved trials of patients with metastatic castration-resistant prostate cancer after androgen receptor signaling inhibition and taxane chemotherapy (or unfit for taxane), who were treated with 177Lu-PSMA-617 and 177Lu-PSMA I&T with a pretreatment screening with 68Ga-PSMA-11 PET/CT, and clinical outcome data, including a prostate-specific antigen (PSA) 50% response rate (PSA50), PSA progression-free survival (PSA-PFS), and overall survival (OS), were included. The screening 68Ga-PSMA-11 PET/CT of all participants was analyzed both semiquantitatively and visually. Semiquantitative analysis was used to derive the SUVmean Visual analysis of the 68Ga-PSMA-11 PET/CT images involved a binary visual heterogeneity assessment (homogeneous or heterogeneous), allocating a tumor SUVmax range (<15, 15-29, 30-49, 50-79, or ≥80). A 4-category score incorporating both heterogeneity and intensity of tumors (HIT) was then developed as a combination of heterogeneity and intensity (SUVmax range). The SUVmax was less than 15 for score 1, 15-79 with heterogeneous intensity for score 2, 15-79 with homogeneous intensity for score 3, and 80 or greater for score 4. This score was evaluated according to clinical outcomes (PSA50, PSA-PFS, and OS) and compared with SUVmean Results: Data from 139 participants were analyzed. In total, 75 (54%) patients achieved a PSA50 with a median PSA-PFS of 5.5 mo (95% CI, 4.1-6.0 mo) and an OS of 13.5 mo (95% CI, 11.1-17.9 mo). SUVmean was associated with PSA50 and survival outcomes when analyzed as a continuous variable or as quartiles. The PSA50 for HIT scores 1-4 was 0%, 39%, 65%, and 76%, respectively. The HIT score was strongly related to PSA-PFS and OS (log-rank test, P < 0.001 and P = 0.002). The median PSA-PFS for HIT scores 1-4 was 1.0, 4.1, 6.0, and 8.5, respectively, and the median OS was 7.6, 12.0, 18.5, and 16.9 mo, respectively. Cohen κ between readers for the HIT score was 0.71. Conclusion: A prostate-specific membrane antigen PET/CT score incorporating HIT derived from tools on a standard PET workstation is comparable with quantitative SUVmean as a prognostic tool following 177Lu-PSMA therapy.

The Prognostic Power of Preablation Stimulated Thyroglobulin in Children With Differentiated Thyroid Cancer

OBJECTIVE

To analyze prognostic factors in children with differentiated thyroid carcinoma (DTC) who have been treated in a single center in the last 27 years.

METHODS

We studied 126 children (≤18 years old) who have been treated with near-total thyroidectomy followed by radioiodine therapy and thyroid hormone replacement. Follow-up of the patients was done 2, 6, and 12 months after treatment and then by yearly evaluation. Response to treatment was defined according to the American Thyroid Association guidelines.

RESULTS

Papillary thyroid cancer was the main pathology (93.7%), and 52.4% of the patients had lymph node metastasis at presentation, which was extensive (>5) in 30% of the patients. Distant metastasis was seen in 8.8%. The mean initial dose of I-131 was 74 ± 42.2 MBq/kg. The median follow-up was 59 months and the median time to achieve an excellent response was 29 months. The preablation stimulated thyroglobulin (psTg) level was 202.4 ± 301.8 ng/mL in patients with first-year incomplete response compared with 11.2 ± 17.5 ng/mL in others (P =.001). Furthermore, using logistic regression, the psTg level was found to be the only significant predictor of distant metastasis, and psTg ≥ 13.75 ng/mL was the most powerful predictor of first-year incomplete response. Moreover, distant metastasis was more common in boys than in girls, and it took longer time for boys to achieve an excellent response.

CONCLUSION

The psTg level was the only significant predictor of distant metastases in children with DTC, and psTg ≥ 13.75 ng/mL was the most powerful predictor of first-year incomplete response.

How to Report PSMA PET

Prostate cancer (PCa) is the most common cancer diagnosed in men in most developed countries and a leading cause of cancer-related morbidity and mortality. Prostate-specific membrane antigen positron emission tomography (PSMA-PET) has become a valuable tool in the staging and assessment of disease recurrence in PCa, and more recently for assessment for treatment eligibility to PSMA radioligand therapy (RLT). Harmonization of PSMA-PET interpretation and synoptic reports are needed to communicate concisely and reproducibly PSMA-PET/CT to referring physicians and to support clinician therapeutic management decisions in various stages of the disease. Uniform image interpretation is also important to provide comparable data between clinical trials and to translate such data from research to daily practice. This review provides an overview of the value of PSMA-PET across the different clinical stages of PCa, discusses published reporting criteria for PSMA-PET, identifies pitfalls in reporting PSMA, and provides recommendations for synoptic reports.

Predictive value and accuracy of [18F]FDG PET/CT modified response criteria for checkpoint immunotherapy in patients with advanced melanoma

PURPOSE

Immune checkpoint inhibitors (ICIs) are widely used in metastatic melanoma and dramatically alter the treatment of these patients. Given the high cost and potential toxicity, a reliable method for evaluating treatment response is needed. In this study, we assessed tumor response in patients with metastatic melanoma treated with ICIs using three modified response criteria: PET Response Evaluation Criteria for Immunotherapy (PERCIMT), PET Response Criteria in Solid Tumors for up to Five Lesions (PERCIST5), and immunotherapy-modified PET Response Criteria in Solid Tumors for up to Five Lesions (imPERCIST5).

METHODS

Ninety-one patients with non-resectable stage IV metastatic melanoma who received ICIs were retrospectively enrolled in this study. Each patient had two [18F]FDG PET/CT scans performed before and after ICI therapy. Responses at the follow-up scan were evaluated according to PERCIMT, PERCIST5, and imPERCIST5 criteria. Patients were classified into four groups: complete metabolic response (CMR), partial metabolic response (PMR), progressive metabolic disease (PMD), and stable metabolic disease (SMD). To assess the "disease control rate," two groups have been defined based on each criterion: patients with CMR, PMR, and SMD as "disease-controlled group (i.e., responders)" and PMD as the "uncontrolled-disease group (i.e., non-responders)". The correspondence between metabolic tumor response defined by these criteria and clinical outcome was assessed and compared.

RESULTS

The response and the disease control rates were 40.7% and 71.4%, 41.8% and 50.5%, and 54.9% and 74.7% based on the PERCIMT, PERCIST5, and imPERCIST5 criteria, respectively. PERCIMT and imPERCIST5 showed significantly different disease control rates from that of PERCIST5 (P < 0.001), whereas it was not significant between PERCIMT and imPERCIST5. Overall survival was significantly longer in the metabolic responder groups than in the non-responder groups based on PERCIMT and PERCIST5 criteria (PERCIMT: 2.48 versus 1.47 years, P = 0.003; PERCIST5: 2.57 versus 1.81 years. P = 0.017). However, according to imPERCIST5 criterion, this difference was not observed (P = 0.12).

CONCLUSION

Although the appearance of new lesions can be secondary to an inflammatory response to ICIs and indicative of pseudoprogression, given the higher rate of true progression, the appearance of new lesions should be interpreted deliberately. Of the three assessed modified criteria, PERCIMT appear to provide more reliable metabolic response assessment that correlates strongly with overall patient survival.

Comparison between viral vector and mRNA based COVID-19 vaccination in prevalence and severity of regional immune reactions, and 18F-FDG PET/CT features

Objectives

The coronavirus pandemic caused by SARS-CoV-2 commenced in late 2019, and global wide vaccination appears to be the only reasonable solution to fight this dreadful virus. There are two main types of COVID-19 immunization using viral vector and mRNA-based vaccines. However, the impact of each of type on ¹⁸F-FDG PET/CT needs to be accurately assessed. This study aimed to compare the ¹⁸F-FDG PET/CT features of these two types of COVID-19 vaccines.

Methods

A total of 188 patients referred for ¹⁸F-FDG PET/CT with a recent history of either BioNTech/Pfizer or AstraZeneca COVID-19 vaccination, and a control group of 40 patients with no history of any type of recent vaccination, were included in the study. ¹⁸F-FDG PET/CT studies of vaccinated patients assessed for injection site uptake and regional nodal and systemic reactions post vaccination. The data were compared to the control group and to the contralateral side for each patient. The findings were compared between patients who received Pfizer and AstraZeneca vaccines.

Results

¹⁸F-FDG PET/CT was semiquantitatively positive in 50.5% of the studied population for vaccine-related features. The ipsilateral axillary and infra- and supraclavicular lymph nodes were significantly larger in size and exhibited higher metabolic activity compared to the contralateral lymph nodes after both types of vaccination. The prevalence of regional nodal reactions post Pfizer and AstraZeneca vaccination was 39% and 17.9% on visual, and 61% and 47.6% on semiquantitative assessments, respectively. Patients receiving the Pfizer vaccine exhibited higher metabolic activity in the ipsilateral regional lymph nodes (p<0.05). No significant difference in the intensity of regional nodal reaction post vaccination was noted between the first four weeks.

Conclusion

Significant local and regional nodal reactions are observed after both viral vector and mRNA COVID-19 vaccination with a tendency to extend toward the infra- and supraclavicular nodal stations but not to the pulmonary hilum. The greater intensity and extension of the nodal reaction after Pfizer vaccination suggests a higher possibility of false-positive results on ¹⁸F-FDG PET/CT studies using mRNA vaccination technology.

More Accurate Imaging Is Not Stage Migration: Time To Move from "Hubble" to "Webb" in Hormone-sensitive Prostate Cancer

Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) produces strikingly superior images compared to conventional imaging, raising the important question of whether conventional imaging is sufficiently accurate to guide patient management. Reducing false positive results with consequent improvement in accuracy is not stage migration and PSMA PET/CT can be a successor to conventional imaging in the staging of metastatic hormone-sensitive prostate cancer.

The value of FDG PET/CT imaging in outcome prediction and response assessment of lymphoma patients treated with immunotherapy: a meta-analysis and systematic review

PURPOSE

Treatment strategies of lymphoid malignancies have been revolutionized by immunotherapy. Because of the inherent property of Hodgkin lymphoma and some subtypes of non-Hodgkin lymphoma as a highly FDG-avid tumor, functional ¹⁸F-FDG PET/CT imaging is already embedded in their routine care. Nevertheless, the question is whether it is still valuable in the context of these tumors being treated with immunotherapy. Herein, we will review the value of ¹⁸F-FDG PET/CT imaging lymphoid tumors treated with immunotherapy regimens.

METHODS

A comprehensive literature search of the PubMed database was conducted on the value of the ¹⁸F-FDG PET/CT for immunotherapy response monitoring of patients with malignant lymphoma. The articles were considered eligible if they met all of the following inclusion criteria: (a) clinical studies on patients with different types of malignant lymphoma, (b) treatment with anti-CD20 antibodies, immune checkpoint inhibitors or immune cell therapies, (c) and incorporated PET/CT with ¹⁸F-FDG as the PET tracer.

RESULTS

From the initial 1488 papers identified, 91 were ultimately included in our study. In anti-CD20 therapy, the highest pooled hazard ratios (HRs) of baseline, early, and late response monitoring parameters for progression-free survival (PFS) belong to metabolic tumor volume (MTV) (3.19 (95%CI: 2.36-4.30)), maximum standardized uptake value (SUVmax) (3.25 (95%CI: 2.08-5.08)), and Deauville score (DS) (3.73 (95%CI: 2.50-5.56)), respectively. These measurements for overall survival (OS) were MTV (4.39 (95%CI: 2.71-7.08)), DS (3.23 (95%CI: 1.87-5.58)), and DS (3.64 (95%CI: 1.40-9.43)), respectively. Early and late ¹⁸F-FDG PET/CT response assessment in immune checkpoint inhibitors (ICI) and immune cell therapy might be an effective tool for prediction of clinical outcome.

CONCLUSION

For anti-CD20 therapy of lymphoma, the MTV as a baseline ¹⁸F-FDG PET/CT-derived parameter has the highest HRs for PFS and OS. The DS as visual criteria in early and late response assessment has higher HRs for PFS and OS compared to the international harmonization project (IHP) visual criteria in anti-CD20 therapy. Early changes in ¹⁸F-FDG PET parameters may be predictive of response to ICIs and cell therapy in lymphoma patients.

Response Evaluation and Survival Prediction After PD-1 Immunotherapy in Patients with Non-Small Cell Lung Cancer: Comparison of Assessment Methods

Immunotherapy using programmed death-1 blockers is a promising modality for non-small cell lung cancer (NSCLC). Therefore, defining the most accurate response criteria for immunotherapy monitoring is of great importance in patient management. This study aimed to compare the correlation between survival outcome and response assessment by PERCIST, version 1.0; immunotherapy-modified PERCIST (imPERCIST); RECIST, version 1.1; and immunotherapy-modified RECIST (iRECIST) in NSCLC patients. Methods: Seventy-two patients with NSCLC who were treated with nivolumab or pembrolizumab and had baseline and follow-up ¹⁸F-FDG PET/CT data were analyzed. The patients were categorized into responders (complete or partial response) and nonresponders (stable or progressive disease) according to PERCIST1 and PERCIST5 (analyzing the peak SUV normalized by lean body mass [SUL_peak] of 1 or up to 5 lesions), imPERCIST1, imPERCIST5, RECIST, and iRECIST. The correlation between achieved response and overall survival (OS) was compared. Results: The overall response rate and the overall disease control rate of the study population were 29% and 74%, respectively. The OS and progression-free survival (PFS) of patients with complete and partial response were statistically comparable. The OS and PFS were significantly different between responders and nonresponders (20.3 vs. 10.6 mo, P = 0.001, for OS and 15.5 vs. 2.2 mo, P < 0.001, for PFS, respectively). Twenty-three (32%) patients with progressive disease according to PERCIST5 had controlled disease according to imPERCIST5; follow-up of patients showed that 22% of these patients had pseudoprogression. The overall incidence of pseudoprogression was 7%. The response rate was 25% and 24% according to PERCIST1 and PERCIST5 (P = 0.2) and 32% and 29% according to imPERCIST1 and imPERCIST5 (P = 0.5), respectively, indicating no significant difference between analyzing the SUL_peak of only the most ¹⁸F-FDG-avid lesion and analyzing up to the 5 most ¹⁸F-FDG-avid lesions. Conclusion: The achieved response by all conventional and immunotherapy-modified methods correlated strongly with patients' survival outcome, with significantly longer OS and PFS in responders than in nonresponders according to all assessed definitions. The most ¹⁸F-FDG-avid lesion according to PERCIST and imPERCIST accurately reflects the overall metabolic response.

Longer Time to Reach Excellent Response to Treatment in Familial Versus Sporadic Non-medullary Thyroid Cancer (NMTC): A Matched Case-Control Study

BACKGROUND

Familial non-medullary thyroid cancer (NMTC) are supposed to be more aggressive and require more frequent treatment compared to non-familial thyroid cancer.

OBJECTIVES

This matched case-control study aimed to compare the response to treatment between the matched case-control groups of familial and sporadic NMTC.

METHODS

This is a retrospective study in patients with familial NMTC (at least one other first-degree relative involved) who were treated with surgery, followed by radio-iodine therapy (RIT) without consideration of its familial origin. Response to treatment was compared between familial NMTC and age, sex, and TNM stage-matched non-familial NMTC (control group). Response to treatment was assessed one and two years after RIT, and time to excellent response was identified.

RESULTS

Out of 2,944 NMTC patients, 81 (2.75%) patients had familial NMTC. We compared 66 patients with familial NMTC and 66 sporadic NMTC patients. There was no significant difference in first thyroglobulin, initial and accumulative iodine dose, and additional treatments (additional surgery and radiotherapy) between patients and controls. Although no significant difference was noted in one and two years' responses to treatment between the case and control groups, familial NMTC patients required more time to achieve excellent response (26.7 ± 24.9 versus 15.9 ± 9.0 months, P = 0.01). No significant difference was noted between familial NMTC patients with two or more than two involved relatives.

CONCLUSIONS

Our study showed that if patients with familial NMTCs were treated in the same way as non-familial patients, the time to excellent response would be significantly longer, even when they have only one other involved relative.

Application of 99mTc-UBI 29-41 scintigraphy in knee periprosthetic infection diagnosis

AIM

 In recent years, the use of total knee arthroplasty (TKA) is considered a safe and cost-effective orthopedic procedure for alleviating the chronic pain and treatment of progressive osteoarthritis. This procedure may have some complications including periprosthetic infection as the most serious and aseptic loosening as the most common one. Differentiating between these entities is important because each has a different therapeutic approach. This study was conducted to investigate the ability of ^99mTC-UBI scan to distinguish septic from aseptic loosening in a painful knee prosthesis.

METHODS

 34 patients with painful knee prostheses were included. The ^99mTC-UBI scan was done immediately after IV administration of ^99mTC-UBI in early dynamic and 30-minute static images. Time-activity curve (TAC) was drawn for all patients and target to non-target ratio (T/NT) was calculated on 30-minute images. The final diagnosis was confirmed by surgical findings, microbiologic culture results or active clinical follow up.

RESULTS

 Using TAC analysis, 24 ^99mTC-UBI scans were considered negative and 10 positive for an infectious process. Sensitivity, specificity, negative and positive predictive values were 56 %, 80 %, 83 %, and 50 %, respectively. T/NT ratio analysis on 30-minute static images demonstrated 9 positive and 25 negative patterns, with a cut off value of 1.83 for the T/NT ratio. The sensitivity, specificity, negative and positive predictive values, and accuracy of this test modality were all 100 %.

CONCLUSIONS

 Our findings show ^99mTc-UBI scan is an excellent clinical diagnostic test for differentiating septic from aseptic loosening of the knee prostheses with perfect sensitivity and specificity. Highly accurate results were obtained only 30 minutes after injection.

Prognostic value and optimal threshold of first thyroglobulin in low/intermediate risk DTC

BACKGROUND

The aim of this study was to define prognostic value and optimal threshold of first thyroglobulin (fTg) measured after thyroidectomy and just before radio-iodine therapy (RIT), in low/intermediate risk patients with differentiated thyroid cancer (DTC).

METHODS

This is a retrospective study in 383 patients with DTC who were treated with surgery followed by RIT. Response to treatment was assessed 1 and 2 years after RIT. Odds ratio of different risk factors like age, sex, TNM stage, fTg and Anti-Tg Ab were compared between patients with and without incomplete response 1 and 2 years after treatment. Receiver operating curve analysis was used for definition of optimal fTg cut off for detection of incomplete response.

RESULTS

218 female and 55 male with DTC had negative anti-Tg antibody (mean age: 37.5±14.5 years) and analyzed separately. fTg≥33.5 ng/mL and fTg/TSH ratio of ≥0.36 had the optimal sensitivity and specificity for detection of incomplete response 1 and 2 years after treatment. fTg<33.5 ng/mL had NPV of 98.5% for exclusion of distant metastases. Patients with fTg≥33.5 ng/mL had longer "time to excellent response" (3.6±2.3 vs. 2.0±1.8 yrs) and needed more additional treatments compared to patients with fTg<33.5 ng/mL. Multivariate analysis showed that fTg was the most potent risk factor for prediction of treatment failure 1 and 2 years after RIT.

CONCLUSIONS

fTg of ≥33.5 ng/mL was the most important risk factor for prediction of treatment failure after RIT and could be included in decision algorithms regarding intensity of treatments in low/intermediate risk patients with DTC.

Comparison of Treatment Response Achieved by Tablet Splitting Versus Whole Tablet Administration of Levothyroxine in Patients with Thyroid Cancer

Objectives

TSH suppression by Levothyroxine consumption is a mainstay of thyroid cancer treatment. Tablet-splitting is a worldwide approach in dose adjustment in patients. However, it is highly recommended to evaluate the validity of tablet splitting for each distinctive drug by clinical trials before routinely using tablet halves in clinical practice. In this study we compared the effect of 150 µg dose of Levothyroxine by use of a100 and a 50 µg tablets or one and half 100 µg tablets in Differentiated thyroid cancer (DTC) patients.

Methods

One hundred DTC patients treated with one and half 100 µg Levothyroxine tablets were randomly divided into two groups. The first group continued taking medication as before and the second group received the same daily dose by taking one 100 and one 50 microgram Levothyroxine tablets. The mean changes in TSH and T3 levels and patients weight were compared between the groups.

Results

91 patients completed the study. Levothyroxine consumption pattern, age, gender distribution, weight and TSH levels were comparable between groups at the beginning of the study. The mean change of body weights, serum levels of T3 and TSH showed no significant difference between groups in different time points during the study (P>0.05).

Conclusion

This study showed similar efficacy of tablet splitting and two tablets administration for Levothyroxine; however, patients preferred two tablets at the end of the study. It can be concluded that tablet splitting can be used as an alternative way when the 50 µg tablet is not available.

Long-Acting Somatostatin Analog Therapy Differentially Alters 68Ga-DOTATATE Uptake in Normal Tissues Compared with Primary Tumors and Metastatic Lesions

Synthetic somatostatin analogs have been posed as a potential source of error in somatostatin receptor imaging through interference with tumor detection; however, experimental models and clinical studies have shown a complex mechanism of the effect of octreotide on tumors. The aim of this study was to assess whether ⁶⁸Ga-DOTATATE uptake before treatment with long-acting somatostatin analogs differs from that after treatment. Methods: Thirty patients (15 men; age [mean ± SD], 64.6 ± 13.4 y) who had intermediately differentiated to well-differentiated neuroendocrine tumors and who underwent ⁶⁸Ga-DOTATATE PET/CT scanning before and after receiving long-acting repeatable octreotide (Sandostatin LAR) were included in the study. The SUV_max and SUV_mean of healthy target organs, residual primary tumor, and up to 5 lesions with the highest SUV_max in each organ were compared before and after octreotide treatment. Results: The mean time interval between the 2 ⁶⁸Ga-DOTATATE studies was 9.6 ± 7.2 mo, and the mean time gap between the last Sandostatin LAR injection and the second ⁶⁸Ga-DOTATATE study was 25.1 ± 14.8 d. The pretreatment mean SUV_max and SUV_mean were both significantly higher in the thyroid, liver, and spleen (P < 0.05) than the values measured after the administration of Sandostatin LAR. No significant differences were found among the uptake indices for residual primary tumor or any metastatic lesions in the liver, bone, lung, or lymph nodes before and after Sandostatin LAR administration (P > 0.05). Conclusion: Long-acting octreotide treatment diminished ⁶⁸Ga-DOTATATE uptake in the liver, spleen, and thyroid but did not compromise tracer uptake in residual primary tumor and metastatic lesions. These findings have a direct impact on the interpretation of ⁶⁸Ga-DOTATATE PET/CT scans.

Relationship between gated myocardial perfusion SPECT findings and hemodynamic, electrocardiographic, and heart rate changes after Dipyridamole infusion

After dipyridamole infusion, electrocardiographic (ECG), blood pressure and heart rate (HR) changes were seen. We tried to investigate whether there is a relationship between hemodynamic, ECG and HR changes after dipyridamole infusion and gated myocardial perfusion SPECT findings. We studied 206 consecutive patients which underwent a 2-day protocol Dipyridamole Stress/Rest Tc99m-Sestamibi gated myocardial perfusion SPECT. Systolic blood pressure (SBP), diastolic blood pressure (DBP), HR and ECG were recorded. HR was mildly increased while SBP and DBP were mildly decreased after Dipyridamole infusion. There was only statistically significant difference between ECG changes as well as transient ischemic dilation (TID) ratio between normal scans and scans with ischemia (P = 0.02 and P = 0.01 respectively). There was correlation between these variables and summed stress score (SSS) and summed difference score (SDS). Patients with ischemia in their scans, 44.3% had ST depression after Dipyridamole infusion. Also ST depression most frequently was seen in patients with left anterior descending artery disease. From patients with abnormal scan + ST depression after Dipyridamole infusion (33 patient), 27 patient (81.81%) had ischemia. There was an association between TID ratio as well as ECG changes after Dipyridamole infusion and SSS, SDS and coronary artery territory abnormality. Difference between calculated left ventricular ejection fraction using stress and rest images had significant correlation with SSS and SDS. ST depression after Dipyridamole infusion and TID ratio had association with ischemia, SSS and SDS. So in equivocal Gated SPECT findings, they could be very useful for interpretation.

Treatment efficacy of (153)Sm-EDTMP for painful bone metastasis

Introduction:

Involvement of the skeleton can cause an excruciating pain in two-thirds of terminal patients with a history of malignancy. Due to several limitations of other therapies, such as analgesics, bisphosphonates, chemotherapy, hormonal therapy and external beam radiotherapy; bone-seeking radiopharmaceuticals have an important role in palliation of pain from bone metastases. Although these kinds of therapies have many advantages including the ability to treat multiple sites of tumoral involvement simultaneously, no significant confliction with other treatments, ease of administration and the potential to be used repetitively; in Iran using of this modality is not widely practiced. In this study we evaluated the clinical usefulness of Sm-153 lexidronamfor pain management of bone metastases.

Methods:

28 patients (14 males and 14 females) aged 38-77 years with a history of painful bone metastases caused by different cancers, not responding to conventional treatments were included in the study. All patients had a recent whole body bone scan indicating multiple bone metastases. 1 mCi/Kg Sm-153 lexidronam was injected intravenously to the patients. Whole body scintigraphy was done 3 or 18 hours post injection. Pain relief and quality of life have been evaluated by analog pain scale and Karnofsky index every week, respectively. Also, all patients were evaluated for hematological toxicity every two weeks. Active follow ups were performed.

Results:

43% of patients showed the presence of the flare phenomenon during the first three days after Sm injection with a mean duration of 2.2 days. The pain relief began between 2 and 16 days post injection and the duration of pain palliation was in the range of 4 to 32 weeks (mean±SD=15.22±7.8). 64.3% of patients showed complete relief of pain and 21.4% achieved partial response to therapy. (Over all response to therapy was 85.7%). The lowest amount of peripheral blood cells was detected in the fourth week for RBCs and in the 6th week for WBCs and PLTs. No one experienced hematological toxicity induced problems.

Conclusion:

Sm-153 lexidronam is an effective treatment for painful bone metastases. The complication rate is low and the quality of life of the patients after treatment would be significantly improved.

Methimazole discontinuation before radioiodine therapy in patients with Graves' disease

INTRODUCTION

Although radioiodine therapy (RIT) has been used for the treatment of hyperthyroidism for many decades, there is no consensus on the optimal time of methimazole (MMI) discontinuation before RIT. The aim of this clinical trial is to study the effect of three different time points of MMI discontinuation on response to RIT.

METHOD AND PATIENTS

Overall, 151 patients (18-65 years old), with Graves' disease who were taking MMI and referred to I-131 therapy, were consecutively assigned to one of three groups, and MMI was discontinued for 24-48, 48.1-72, and 72.1-168 h in group, 1, 2, and 3, respectively. Radioiodine uptake was measured in all patients and the radioiodine dose was calculated according to the Quimby formula to deliver 7.4 MBq of I-131 per gram of thyroid weight. Response to RIT was assessed at 1, 3, 6, and 12 months after RIT.

RESULTS

A total of 102 women and 49 men were included in the study. The mean administered dose of I-131 was 362.9±188.7 MBq (9.8±5.1 mCi) and the mean time to response for radioiodine was 4.1±3.6 months. There was no significant difference between the three groups in age, thyroid weight, anti-TPO level, radioactive iodine uptake level, and radioiodine dose (P>0.1). Response to RIT at 1, 3, 6, and 12 months after administration was also not different between the three groups (P>0.57).

CONCLUSION

No difference was found in the response to treatment between patients with MMI discontinuation for 24-48, 48.1-72, and 72.1-96 h before RIT. Shorter discontinuation of MMI before RIT may be preferable in most patients. Video Abstract: http://links.lww.com/NMC/A39.

Diffuse skeletal metastasis and low thyroglobulin level in a pediatric patient with papillary thyroid carcinoma

Thyroglobulin (Tg) is frequently measured in follow-up of patients with differentiated thyroid carcinoma. A low stimulated Tg level (<1 ng/ml) associated with normal neck ultrasonography is considered as the most reliable criteria for complete remission in low risk patients. We are reporting a case of pediatric thyroid cancer with diffuse skeletal metastasis associated with low serum Tg level bringing a point of caution in evaluation of patients with low Tg.

Carum induced hypothyroidism: an interesting observation and an experiment

Carum carvi is a widely available herb that has been used as a food additive and as a medication in traditional medicine for many years. Its potential biological effects include analgesic, anti-inflammatory, anti-anxiety and antispasmodic activities. We report a patient with papillary thyroid carcinoma who were under treatment with levothyroxine and experienced an elevated TSH level by ingestion of Carum carvi. TSH level was increased to 60.3 mIU/L with no change in levothyroxine dosage and decreased to normal range after discontinuation of the Carum carvi. Observing this dramatic change in TSH level by carum ingestion, carum carvi capsules was produced and one of the researcher tried the medication on herself with a dose of 40 mg/kg/day. She had a history of hypothyroidism and was taking 100 ugr/day of levothyroxine. TSH was markedly increased 2 weeks after ingestion of Carum carvi and returned to normal range 5 months after discontinuation of it. This case report shows the effect of consumption of Carum carvi in increasing TSH level in hypothyroid patients treating with levothyroxine. The exact mechanism of action of carum carvi remains unknown.

Comparison between fragmented QRS and Q waves in myocardial scar detection using myocardial perfusion single photon emission computed tomography

BACKGROUND

Accurate diagnosis of myocardial infarction (MI) is of paramount importance in patient management, which necessitates the development of efficient and accurate diagnostic methods. Q wave is not present in all patients with MI, and its prevalence is declining. Recently, fragmented QRS (fQRS) complex has been introduced as a marker of prior MI.

AIM

To investigate diagnostic value of fQRS compared to Q wave.

METHODS

We included 500 consecutive patients with known or suspected coronary artery disease who underwent two days of gated myocardial perfusion imaging using dipyridamole pharmacologic stress. Electrocardiogram (ECG) was evaluated to detect fQRS as well as Q-wave. Finally, subjects were compared in terms of ventricular perfusion and function indices.

RESULTS

A total of 207 men and 269 women with mean age of 57.06 ± 12 years were studied. ECG analysis showed that 14.3% of the patients had both fQRS and Q waves, 30.7% had fQRS, and 3.8% had Q waves. Fixed myocardial perfusion defect was noted in 22.3% of patients according to MPIs. Sensitivity, specificity, and positive and negative predictive values for myocardial scar detection were 78%, 65%, 39%, and 91%, respectively, for fQRS and 61%, 94%, 76%, and 89%, respectively, for Q wave.

CONCLUSIONS

Although fQRS had lower specificity compared to Q wave in the detection of myocardial scar, due to higher sensitivity and negative predictive value can be an invaluable diagnostic index. There is also an incremental value for fQRS in association with Q-wave in myocardial scar assessment.

Ectopic papillary thyroid carcinoma in the mediastinum without any tumoral involvement in the thyroid gland. A Case report

Ectopic thyroid tissue results from abnormal embryologic development and migration of the thyroid gland. True malignant transformation in ectopic thyroid tissue is extremely rare and is always diagnosed after surgical excision of the lesion by pathology examinations. There are well-documented cases of ectopic thyroid cancer while primary tumoral lesion occurs in the orthotopic thyroid, but only rare cases of ectopic PTC without any evidence of occult thyroid cancer in the orthotopic thyroid or cervical lymph nodes have been reported. We report on a 39 year old woman who was operated for a mediastinal mass. The initial diagnosis was a malignant thymic lesion, which was later confirmed to be a papillary thyroid carcinoma. Consequently, total thyroidectomy was performed and pathology report showed normal thyroid tissue with no evidence of any neoplastic involvement. Until now, only one similar case has been reported.

(99m)Tc-labeled ubiquicidin scintigraphy: a promising method in hip prosthesis infection diagnosis

AIM

Hip prosthesis implantation has witnessed a significant increase in recent years. Despite the advantages of this surgical procedure, it has some complications, the most serious of which is prosthetic infection. This study was conducted to investigate the feasibility of 99mTc-UBI scintigraphy in detection of infectious foci in painful hip prosthesis. UBI (Ubiquicidin 29-41) is an antimicrobial peptide fragment with the ability to target the bacterial colony directly.

PATIENTS, METHODS

34 patients, aged 20-79 years, with painful hip prosthesis were included. 99mTc-UBI scan and three phase bone scan were performed and two nuclear medicine specialists interpreted the UBI scans with and without bone scan results at hand. Both qualitative and semi-quantitative methods were used to interpret the 30 minute post injection images. The patients were actively followed up. According to the surgical findings, microbiological culture and active follow up, final diagnosis was made.

RESULTS

24 negative and 10 positive UBI scans were recorded. The sensitivity, specificity, negative and positive predictive values and accuracy of the study were all 100%. Bone scan did not have any influence on UBI interpretation. We were able to achieve excellent differentiation between infected and non-infected prostheses with a cut off value of 1.8 for target to non target (T/NT) ratio. No adverse effects were noticed following UBI scan.

CONCLUSION

Based on the findings, the authors believe that 99mTc-UBI scintigraphy, with its high sensitivity and specificity, provides the physician with an excellent tool for differentiating infection from aseptic loosening of hip prostheses. Using this radiopharmaceutical, it is possible to obtain highly accurate results only 30 minutes after the beginning of the study.