David Chee Eng Ng

High SUV uptake on FDG–PET/CT predicts for an aggressive B-cell lymphoma in a prospective study of primary FDG–PET/CT staging in lymphoma

BACKGROUND Data assessing the role of positron emission tomography (PET)/computed tomography (CT) imaging in lymphoma staging is still being accumulated and current staging is based primarily on CT. This study aims to compare the value of PET/CT over conventional CT and bone marrow biopsy (BMB) in the initial evaluation of patients with lymphoma. METHODS Data on 122 patients with PET/CT scans as part of their initial staging were prospectively collected and reviewed. All patients had complete staging, including BMB. RESULTS Among the 122 patients, 101 had non-Hodgkins lymphoma (NHL) and 21 had Hodgkins lymphoma (HL). Compared with conventional CT, PET/CT upstaged 21 (17%) cases [B-cell non-Hodgkins lymphoma (B-NHL), 12; T-cell non-Hodgkins lymphoma (T-NHL), 3; HL, 6]. Of significance, in 13 patients with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG)-avid splenic lesions, four had normal CT findings. A maximum FDG uptake of >10 standardized uptake value (SUV) seems to significantly correlate with an aggressive B-cell lineage (odds ratio 2.47, 95% confidence interval 2.23-2.70). Overall, PET scan was concordant with BMB results in 108 (89%) and discordant in 14 (11%) cases. In HL, our data show that PET scan and marrow results agreed in 19 of the cases (90%), being concordantly negative in 18 cases and concordantly positive in one, giving a negative predictive value (NPV) of 100%, sensitivity of 100% and specificity of 90%. Of note, all 13 with early-stage HL had negative PET/CT scan and BMB. In NHL, all 17 cases of T-NHL had concordant PET and BMB results. In patients with aggressive B-NHL, BMB and PET/CT agreed in 58 patients (92%) and disagreed in five (8%), while the corresponding rates in indolent B-cell lymphoma were 14 (67%) and seven patients (33%), respectively. All seven were falsely negative. CONCLUSIONS PET/CT upstages 17% of cases and detects occult splenic involvement. This may have potential therapeutic and prognostic implications. SUV >10 may predict for an aggressive histology. Except for indolent B-NHL, our data show that PET scans have a good overall NPV in excluding lymphomatous bone marrow involvement. This is particularly true of early-stage HL, suggesting that BMB may be safely omitted in this group.

Comparison of 4 modalities for distant metastasis staging in endemic nasopharyngeal carcinoma

Endemic nasopharyngeal carcinoma (NPC) commonly metastasizes to the lungs, liver, and bones. This study aims to assess the efficacy of 4 distant metastasis staging modalities, namely (1) conventional work‐up comprising chest X‐ray, liver ultrasound, and skeletal scintigraphy, (2) CT of the thorax, abdomen, and skeletal scintigraphy, (3) (18)F‐fluorodeoxyglucose positron emission tomography (FDG‐PET), and (4) integrated FDG‐PET/CT.

Positron emission tomography with CT in the evaluation of non-small cell lung cancer in populations with a high prevalence of tuberculosis.

Objective and background:  To determine the utility of positron emission tomography with CT (PET‐CT) in the evaluation of non‐small cell lung cancer (NSCLC) in an Asian context where tuberculosis rates are moderately high.

Promising role of [18F] fluorocholine PET/CT vs [18F] fluorodeoxyglucose PET/CT in primary brain tumors—Early experience

Primary brain tumors (PBT), in particular gliomas, are among the most difficult neoplasms to treat, necessitating good quality imaging to guide clinicians at many junctures. Current imaging modalities, including [18F] fluorodeoxyglucose (FDG) PET/CT, MRI and MR spectroscopy (MRS), have various limitations, particularly with regard to differentiating tumor from radiation induced necrosis (RIN) and from normal cerebral metabolic uptake. [18F] fluorocholine (FCH) is an analog of choline with potentially optimal imaging characteristics, as pharmacokinetic studies with FCH conducted in patients showed minimal FCH uptake by normal brain parenchyma, whereas high-grade tumors are known to have increased choline uptake. We present two cases of our early experience with FCH PET/CT for patients with PBT and discuss the potential use and comparative limitations of this imaging modality.

[18F] FDG PET/CT in patients with fever of unknown origin: a local experience.

Objective2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography ([18F] FDG PET/CT) has become an established imaging tool in oncology and is now emerging in the field of infectious disease. The aim of this study is to assess the value of fluorine [18F] FDG PET/CT in the investigation of patients with fever of unknown origin (FUO). Methods[18F] FDG PET/CT scans and clinical data of 12 patients were reviewed. These patients met the revised definition criteria of FUO (febrile illness of greater than 3 weeks duration, temperature greater than 38.3°C and no diagnosis after at least 3 days of in-patient investigation or 2 weeks of outpatient investigation). A retrospective analysis of our local database was performed and evaluated for the diagnostic contribution of [18F] FDG PET/CT scans. ResultsAn infective cause of the FUO was found in four (33.3%) patients, a neoplasm in two (16.7%) patients, non-infectious inflammatory disease or autoimmune in one (8.3%) patient. A definitive causative agent could not be found in five (41.7%) patients despite extensive investigations.In all, five (41.6%) patients had a PET/CT scan that was abnormal and was deemed ‘helpful’ as part of the investigation that pointed to the final diagnosis. Two (16.7%) patients had abnormal scans, which were deemed ‘not-helpful’ for the final diagnosis. Conclusion[18F] FDG PET/CT can be helpful in some patients with FUO. This study adds value to the limited data published so far on this subject.

Underlying liver disease influences volumetric changes in the spared hemiliver after selective internal radiation therapy with 90Y in patients with hepatocellular carcinoma

Hypertrophy of the contralateral liver lobe after treatment with yttrium‐90 (90Y) microspheres has recently been reported. This study aimed to quantify left hepatic lobe hypertrophy after right‐sided radioembolization for hepatocellular carcinoma (HCC) and to identify pretreatment predictive factors of hypertrophy in an Asian population.

SIRveNIB: Selective Internal Radiation Therapy Versus Sorafenib in Asia-Pacific Patients With Hepatocellular Carcinoma

Purpose Selective internal radiation therapy or radioembolization (RE) shows efficacy in unresectable hepatocellular carcinoma (HCC) limited to the liver. This study compared the safety and efficacy of RE and sorafenib in patients with locally advanced HCC. Patients and Methods SIRveNIB (selective internal radiation therapy v sorafenib), an open-label, investigator-initiated, phase III trial, compared yttrium-90 (90Y) resin microspheres RE with sorafenib 800 mg/d in patients with locally advanced HCC in a two-tailed study designed for superiority/detriment. Patients were randomly assigned 1:1 and stratified by center and presence of portal vein thrombosis. Primary end point was overall survival (OS). Efficacy analyses were performed in the intention-to-treat population and safety analyses in the treated population. Results A total of 360 patients were randomly assigned (RE, 182; sorafenib, 178) from 11 countries in the Asia-Pacific region. In the RE and sorafenib groups, 28.6% and 9.0%, respectively, failed to receive assigned therapy without significant cross-over to either group. Median OS was 8.8 and 10.0 months with RE and sorafenib, respectively (hazard ratio, 1.1; 95% CI, 0.9 to 1.4; P = .36). A total of 1,468 treatment-emergent adverse events (AEs) were reported (RE, 437; sorafenib, 1,031). Significantly fewer patients in the RE than sorafenib group had grade ≥ 3 AEs (36 of 130 [27.7%]) v 82 of 162 [50.6%]; P < .001). The most common grade ≥ 3 AEs were ascites (five of 130 [3.8%] v four of 162 [2.5%] patients), abdominal pain (three [2.3%] v two [1.2%] patients), anemia (zero v four [2.5%] patients), and radiation hepatitis (two [1.5%] v zero [0%] patients). Fewer patients in the RE group (27 of 130 [20.8%]) than in the sorafenib group (57 of 162 [35.2%]) had serious AEs. Conclusion In patients with locally advanced HCC, OS did not differ significantly between RE and sorafenib. The improved toxicity profile of RE may inform treatment choice in selected patients.

Dosimetric Considerations in Radioimmunotherapy and Systemic Radionuclide Therapies: A Review

Radiopharmaceutical therapy, once touted as the “magic bullet” in radiation oncology, is increasingly being used in the treatment of a variety of malignancies; albeit in later disease stages. With ever-increasing public and medical awareness of radiation effects, radiation dosimetry is becoming more important. Dosimetry allows administration of the maximum tolerated radiation dose to the tumor/organ to be treated but limiting radiation to critical organs. Traditional tumor dosimetry involved acquiring pretherapy planar scans and plasma estimates with a diagnostic dose of intended radiopharmaceuticals. New advancements in single photon emission computed tomography and positron emission tomography systems allow semi-quantitative measurements of radiation dosimetry thus allowing treatments tailored to each individual patient.

National Cancer Centre Singapore Consensus Guidelines for Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the 6th most common cancer in the world, but the second most common cause of cancer death. There is no universally accepted consensus practice guidelines for HCC owing to rapid developments in new treatment modalities, the heterogeneous epidemiology and clinical presentation of HCC worldwide. However, a number of regional and national guidelines currently exist which reflect practice relevant to the epidemiology and collective experience of the consensus group. In 2014, clinicians at the multidisciplinary Comprehensive Liver Cancer Clinic (CLCC) at the National Cancer Centre Singapore (NCCS) reviewed the latest published scientific data and existing international and regional practice guidelines, such as those of the National Comprehensive Cancer Network, American Association for the Study of Liver Diseases and the Asian Pacific Association for the Study of the Liver, and modified them to reflect local practice. These would serve as a template by which treatment outcomes can be collated and benchmarked against international data. The NCCS Consensus Guidelines for HCC have been successfully implemented in the CLCC since their publication online on 26th September 2014, and the guidelines allow outcomes of treatment to be compared to international data. These guidelines will be reviewed periodically to incorporate new data.

Yttrium-90 hepatic radioembolization: clinical review and current techniques in interventional radiology and personalized dosimetry

In recent years, yttrium-90 ((90)Y) microsphere radioembolization has been establishing itself as a safe and efficacious treatment for both primary and metastatic liver cancers. This extends to both first-line therapies as well as in the salvage setting. In addition, radioembolization appears efficacious for patients with portal vein thrombosis, which is currently a contraindication for surgery, transplantation and transarterial chemoembolization. This article reviews the efficacy and expanding use of (90)Y microsphere radioembolization with an added emphasis on recent advances in personalized dosimetry and interventional radiology techniques. Directions for future research into combination therapies with radioembolization and expansion into sites other than the liver are also explored.