Eddie Lau

Abdominal Manifestations of Extranodal Lymphoma: Spectrum of Imaging Findings

OBJECTIVE The purpose of this article is to illustrate the spectrum of appearances of extranodal lymphoma in the abdomen using cross-sectional imaging techniques. CONCLUSION Extranodal lymphoma in the abdomen can mimic other neoplastic or inflammatory conditions. Although a definitive diagnosis is possible only with biopsy, it is important to consider extranodal lymphoma in the presence of certain imaging appearances in the appropriate clinical setting for the correct diagnosis, accurate staging, and optimal management.

How do oncologists deal with incidental abnormalities on whole-body fluorine-18 fluorodeoxyglucose PET/CT?

Combined positron emission tomography (PET)/computed tomography (CT) using fluorine‐18 fluorodeoxyglucose (FDG) is an exciting technique for cancer evaluation, but false‐positive results are a recognized limitation. The aim of the study was to evaluate how oncologists deal with focal extrathyroidal FDG abnormalities considered by imaging specialists to be unrelated to the referral indication.

Comparative PET study using F-18 FET and F-18 FDG for the evaluation of patients with suspected brain tumour

The aim of this prospective pilot study in patients with suspected or known brain tumour was to establish the diagnostic value of O-(2-[(18)F]-fluoroethyl)-L-tyrosine (FET) positron emission tomography (PET) when compared to fluorine-18 fluorodeoxyglucose (FDG) PET. Twenty-five FET PET and FDG PET scans were performed on 21 consecutive patients within 24 months. Final malignant pathology included 11 glioma (eight low-grade, three high grade), two lymphoma, one olfactory ganglioneuroblastoma, one anaplastic meningioma. Benign pathology included two encephalitis and one cortical dysplasia. Definitive pathology was not available in three patients. The accuracy of PET was determined by subsequent surgical histopathology in 12 and clinical/imaging course in nine patients. Median follow-up period was 20 months. FET sensitivity was 93%, specificity 100%, accuracy 96%, positive predictive value (PPV) 100% and negative predictive value (NPV) 91%. FDG sensitivity was 27%, specificity 90%, accuracy 52%, PPV 80% and NPV 45%. FET PET is more accurate than FDG PET for detecting malignant brain lesions, especially low-grade gliomas.

Minimising critical organ irradiation in limited stage Hodgkin lymphoma: a dosimetric study of the benefit of involved node radiotherapy

BACKGROUND Chemotherapy plus radiotherapy is the standard of care for patients with limited stage Hodgkin lymphoma (HL). Radiotherapy is evolving from involved field radiotherapy (IFRT) to involved node radiotherapy (INRT) to decrease radiotherapy-related morbidity. In the absence of long-term toxicity data, dose-volume metrics of organs at risk (OAR) provide a surrogate measure of toxicity risk. PATIENTS AND METHODS Ten female patients with stage I-IIA supradiaphragmatic HL were randomly selected. All patients had pre-chemotherapy computerised tomography (CT) and CT-positron emission tomography staging. Using CT planning, three radiotherapy plans were produced per patient: (i) IFRT, (ii) INRT using parallel-opposed beams and (iii) INRT using volumetric modulated arc therapy (VMAT). Radiotherapy dose was 30.6 Gy in 1.8 Gy fractions. OAR evaluated were lungs, breasts, thyroid, heart and coronary arteries. RESULTS Compared with IFRT, INRT significantly reduced mean doses to lungs (P < 0.01), breasts (P < 0.01), thyroid (P < 0.01) and heart (P < 0.01), on Wilcoxon testing. Compared with conventional INRT, VMAT improved dose conformality but increased low-dose radiation exposure to lungs and breasts. VMAT reduced the heart volume receiving 30 Gy (V30) by 85%. CONCLUSIONS Reduction from IFRT to INRT decreased the volumes of lungs, breasts and thyroid receiving high-dose radiation, suggesting the potential to reduce long-term second malignancy risks. VMAT may be useful for patients with pre-existing heart disease by minimising further cardiac toxicity risks.BACKGROUND Chemotherapy plus radiotherapy is the standard of care for patients with limited stage Hodgkin lymphoma (HL). Radiotherapy is evolving from involved field radiotherapy (IFRT) to involved node radiotherapy (INRT) to decrease radiotherapy-related morbidity. In the absence of long-term toxicity data, dose-volume metrics of organs at risk (OAR) provide a surrogate measure of toxicity risk. PATIENTS AND METHODS Ten female patients with stage I-IIA supradiaphragmatic HL were randomly selected. All patients had pre-chemotherapy computerised tomography (CT) and CT-positron emission tomography staging. Using CT planning, three radiotherapy plans were produced per patient: (i) IFRT, (ii) INRT using parallel-opposed beams and (iii) INRT using volumetric modulated arc therapy (VMAT). Radiotherapy dose was 30.6 Gy in 1.8 Gy fractions. OAR evaluated were lungs, breasts, thyroid, heart and coronary arteries. RESULTS Compared with IFRT, INRT significantly reduced mean doses to lungs (P < 0.01), breasts (P < 0.01), thyroid (P < 0.01) and heart (P < 0.01), on Wilcoxon testing. Compared with conventional INRT, VMAT improved dose conformality but increased low-dose radiation exposure to lungs and breasts. VMAT reduced the heart volume receiving 30 Gy (V30) by 85%. CONCLUSIONS Reduction from IFRT to INRT decreased the volumes of lungs, breasts and thyroid receiving high-dose radiation, suggesting the potential to reduce long-term second malignancy risks. VMAT may be useful for patients with pre-existing heart disease by minimising further cardiac toxicity risks.

In vivo tracking of dendritic cells in patients with multiple myeloma.

Dendritic cell (DC) immunotherapy is being actively studied in multiple myeloma (MM). We aimed to use positron emission tomography or single positron emission tomography to determine the in vivo distribution of monocyte-derived nonmatured DC or matured DC (mDC) administered to patients with MM. Eligible patients had stable or slowly progressive MM and elevated serum MUC-1 or MUC-1 expression on marrow plasma cells. DCs were derived from granulocyte-macrophage colony-stimulating factor+interleukin-13 stimulated autologous monocytes, pulsed with mannan-MUC1 fusion protein, and matured by FMKp and interferon-γ. Before injection, DCs were labeled with either 18fluorine-fluorodeoxyglucose, 111indium-oxine or 64copper-pyruvaldehyde-bis-N-4-methylthiosemicarbazone. Labeled DCs were given either as a single intravenous dose or by concurrent subcutaneous (SC), intradermal (ID), and intranodal routes. 18Fluorine-fluorodeoxyglucose tracking was unsuccessful owing to high radiolabel efflux. 64Copper-pyruvaldehyde-bis-N-4-methylthiosemicarbazone-labeled mDC (n=2 patients) demonstrated tracking to regional nodes but quantitation was also limited owing to cellular efflux. 111Indium-oxine, however, gave reproducible tracking of both nmDc and mDC (n=6) to regional lymph node after either SC or ID administration, with mDC revealing superior migration to regional lymph node. SC and ID routes produced similar levels of DC migration.

PET/CT: will it change the way that we use CT in cancer imaging?

Accurate staging of cancer is of fundamental importance to treatment selection and planning. Current staging paradigms focus, first, on a detailed delineation of the primary tumour in order to determine its suitability for resection, and, thereafter, on assessment of the presence of metastatic spread that would alter the surgical approach, or mandate non-surgical therapies. This approach has, at its core, the assumption that the best, and sometimes the only, way to cure a patient of cancer is by surgical resection. Unfortunately, all non-invasive techniques in current use have imperfect ability to identify those primary tumours that are able to be completely excised, and even worse ability to define the extent of metastatic spread. Nevertheless, because of relatively low cost and widespread availability, computed tomography (CT) scanning is the preferred methodology for tumour, nodal and systemic metastasis (TNM) staging. This is often supplemented by other tests that have improved performance in particular staging domains. For example, magnetic resonance imaging (MRI), mammography, or endoscopic ultrasound may be used as complementary tests for T-staging; surgical nodal sampling for N-staging; and bone scanning, MRI or ultrasound for M-staging. Accordingly, many patients undergo a battery of investigations but, even then, are found to have been incorrectly staged based on subsequent outcomes. Even for those staged surgically, pathology can only identify metastases within the resection specimens and has no capability for detecting remote disease. As a result of this, many patients undergo futile operations for disease that could never have been cured by surgery. In the case of restaging, the situation is even worse. The sequelae of prior treatment can be difficult to differentiate from residual cancer and the likelihood of successful salvage therapy is even less than at presentation. More deleteriously, patients may be subjected to additional morbid treatments when cure has already been achieved. Thus, in post-treatment follow-up, the presence and extent of disease is equally critical to treatment selection and patient outcome as it is in primary staging. One of the major strengths of positron emission tomography (PET)/CT as a cancer staging modality is its ability to identify systemic metastases. At any phase of cancer evaluation, demonstration of systemic metastasis has profound therapeutic and prognostic implications. Only in the absence of systemic metastasis does nodal status become important, and only when unresectable nodal metastasis has been excluded does T-stage become important. There are now accumulating data that PET/CT could be used as the first, rather than the last test to assess M- and N-stage for evaluating cancers with an intermediate to high pre-test likelihood of metastatic disease based on poor long-term survival. In this scenario, there is great opportunity for subsequently selecting and tailoring the performance of anatomically based imaging modalities to define the structural relations of abnormalities identified by PET, when this information would be of relevance to management planning. Primary staging of oesophageal cancer and restaging of colorectal cancer are illustrative examples of a new paradigm for cancer imaging.

Early post‐treatment pseudo‐progression amongst glioblastoma multiforme patients treated with radiotherapy and temozolomide: A retrospective analysis

Introduction: To evaluate the incidence and impact of early post‐chemoradiation (cRT) ‘pseudoprogression’ (PsPD) amongst glioblastoma multiforme (GBM) patients treated with the current standard of care – 60 Gy conformal radiotherapy with concurrent low‐dose temozolomide, followed by six cycles of high‐dose temozolomide (the ‘Stupp protocol’).

Imaging of nonthrombotic pulmonary embolism: Biological materials, nonbiological materials, and foreign bodies

Nonthrombotic pulmonary embolism is defined as embolization to the pulmonary circulation caused by a wide range of substances of endogenous and exogenous biological and nonbiological origin and foreign bodies. It is an underestimated cause of acute and chronic embolism. Symptoms cover the entire spectrum from asymptomatic patients to sudden death. In addition to obstruction of the pulmonary vasculature there may be an inflammatory cascade that deteriorates vascular, pulmonary and cardiac function. In most cases the patient history and radiological imaging reveals the true nature of the patients condition. The purpose of this article is to give the reader a survey on pathophysiology, typical clinical and radiological findings in different forms of nonthrombotic pulmonary embolism. The spectrum of forms presented here includes pulmonary embolism with biological materials (amniotic fluid, trophoblast material, endogenous tissue like bone and brain, fat, Echinococcus granulosus, septic emboli and tumor cells); nonbiological materials (cement, gas, iodinated oil, glue, metallic mercury, radiotracer, silicone, talc, cotton, and hyaluronic acid); and foreign bodies (lost intravascular objects, bullets, catheter fragments, intraoperative material, radioactive seeds, and ventriculoperitoneal shunts).

High-Administered Activity In-111 Octreotide Therapy with Concomitant Radiosensitizing 5FU Chemotherapy for Treatment of Neuroendocrine Tumors: Preliminary Experience

INTRODUCTION High-administered activity In-111 octreotide (HA-Oc) therapy has been used for patients with disseminated neuroendocrine tumors (NET) with high somatostatin receptor (SSR) expression. Combining HA-Oc with radiosensitizing 5-fluorouracil (5FU) chemotherapy could enhance efficacy. Our other aim was to assess whether concomitant 5FU would contribute to significant additional toxicity. METHODS Fifteen (15) consecutive patients who received 3 cycles of HA-Oc+5FU were evaluated. Symptomatic, octreoscan, computed tomography (CT), hormonal responses, and toxicity were reviewed at 3 months post-last treatment. Long-term follow-up was performed to death or April 2008 to assess late toxicity and time to progression requiring retreatment. RESULTS At 3 months post-treatment, 67% of patients had symptomatic improvement, with 20% experiencing a complete resolution of symptoms. Overall, 90% achieved stabilization or a decrease in hormone levels. Octreoscan improvement/stabilization occurred in 95% and CT stabilization in 80% of patients with previously progressive disease, but no partial or complete regression by Response Evaluation Criteria in Solid Tumors criteria. Transient lymphopenia and nausea were the most common side-effects, and there was no significant renal or grade 4 hematologic toxicity. Subacute side-effects included a peripherally inserted central catheter line thrombosis (1 patient), discomfort/pain associated with lesion necrosis, and 1 lymph node swelling. Median time to retreatment was 23 months (range, 6-34) for 10 patients. Six (6) patients deceased (no deaths directly related to 5FU); 9 patients (60%) are alive at 36-139 months. CONCLUSIONS HA-Oc+5FU achieve a high rate of symptomatic response associated with stabilization/improvement in hormonal and functional scan abnormalities. Combination treatment achieved disease stabilization in the majority of patients with previously progressive disease. There was no significant observed increase in toxicity with additional 5FU, making it a promising adjunct to radiopeptide receptor therapy for progressive NET.

Imaging in the diagnosis and treatment of non‐small cell lung cancer

Abstract:  The available tools for diagnosing and staging lung cancer patients can be broadly categorized into non‐invasive, minimally invasive and invasive (surgical) modalities. Non‐invasive modalities include CT and PET. Minimally invasive modalities are endoscopic approaches, including endoscopic ultrasound, endobronchial ultrasound and transbronchial fine needle aspiration without ultrasound guidance. This review focuses on the non‐invasive and minimally invasive techniques involving imaging. Application of Bayesian principles indicates that tests with a high sensitivity and specificity for detection of both systemic metastases and mediastinal nodal involvement are required for treatment selection and planning in patients with non‐small cell lung cancer who would be considered for treatment with curative intent. Combined PET/CT using the glucose analogue fluorine‐18 fluorodeoxyglucose currently provides the best diagnostic performance for this purpose and should now be considered the standard of care for staging non‐small cell lung cancer. Endoscopic ultrasound and endobronchial ultrasound have important complementary roles to allow further evaluation of equivocal nodal abnormalities on PET or CT and to allow pathological samples to be obtained. Diagnostic CT has an important role in defining tumour relations for patients deemed suitable for surgical resection and as the initial investigation for patients with potential symptoms of lung cancer or proven lung cancer that would not be considered for curative treatment on medical grounds.