The relationship between tumour dosimetry, response, and overall survival in patients with unresectable Neuroendocrine Neoplasms (NEN) treated with 177Lu DOTATATE (LuTate)

Peptide Receptor Radionuclide Therapy (PRRT) delivers targeted radiation to Somatostatin Receptor (SSR) expressing Neuroendocrine Neoplasms (NEN). We sought to assess the predictive and prognostic implications of tumour dosimetry with respect to response by 68 Ga DOTATATE (GaTate) PET/CT molecular imaging tumour volume of SSR (MITVSSR) change and RECIST 1.1, and overall survival (OS).

METHODS

Patients with gastro-entero-pancreatic (GEP) NEN who received LuTate followed by quantitative SPECT/CT (Q-SPECT/CT) the next day (Jul 2010 to Jan 2019) were retrospectively reviewed. Single time-point (STP) lesional dosimetry was performed for each cycle using population-based pharmacokinetic modelling. MITVSSR and RECIST 1.1 were measured at 3-months post PRRT.

RESULTS

Median of 4 PRRT cycles were administered to 90 patients (range 2-5 cycles; mean 27.4 GBq cumulative activity; mean 7.6 GBq per cycle). 68% received at least one cycle with radiosensitising chemotherapy (RSC). RECIST 1.1 partial response was 24%, with 70% stable and 7% progressive disease. Cycle 1 radiation dose in measurable lesions was associated with local response (odds ratio 1.5 per 50 Gy [95% CI: 1.1-2.0], p = 0.002) when adjusted by tumour grade and RSC. Median change in MITVSSR was -63% (interquartile range -84 to -29), with no correlation with radiation dose to the most avid lesion on univariable or multivariant analyses (5.6 per 10 Gy [95% CI: -1.6, 12.8], p = 0.133). OS at 5-years was 68% (95% CI: 56-78%). Neither baseline MITVSSR (hazard ratio 1.1 [95% CI: 1.0, 1.2], p = 0.128) nor change in baseline MITVSSR (hazard ratio 1.0 [95% CI: 1.0, 1.1], p = 0.223) were associated with OS when adjusted by tumour grade and RSC but RSC was (95% CI: 0.2, 0.8, p = 0.012).

CONCLUSION

Radiation dose to tumour during PRRT was predictive of radiologic response but not survival. Survival outcomes may relate to other biological factors. There was no evidence that MITVSSR change was associated with OS, but a larger study is needed.

Perspectives on joint EANM/SNMMI/ANZSNM practice guidelines/procedure standards for [18F]FDG PET/CT imaging during immunomodulatory treatments in patients with solid tumors

Response assessment in the context of immunomodulatory treatments represents a major challenge for the medical imaging community and requires a multidisciplinary approach with involvement of oncologists, radiologists, and nuclear medicine specialists. There is evolving evidence that [¹⁸F]FDG PET/CT is a useful diagnostic modality for this purpose. The clinical indications for, and the principal aspects of its standardization in this context have been detailed in the recently published "Joint EANM/SNMMI/ANZSNM practice guidelines/procedure standards on recommended use of [¹⁸F]FDG PET/CT imaging during immunomodulatory treatments in patients with solid tumors version 1.0". These recommendations arose from a fruitful collaboration between international nuclear medicine societies and experts in cancer treatment. In this perspective, the key elements of the initiative are reported, summarizing the core aspects of the guidelines for radiologists and nuclear medicine physicians. Beyond the previous guidelines, this perspective adds further commentary on how this technology can advance development of novel therapeutic approaches and guide management of individual patients.

Joint EANM/SNMMI/ANZSNM practice guidelines/procedure standards on recommended use of [18F]FDG PET/CT imaging during immunomodulatory treatments in patients with solid tumors version 1.0

PURPOSE

The goal of this guideline/procedure standard is to assist nuclear medicine physicians, other nuclear medicine professionals, oncologists or other medical specialists for recommended use of [18F]FDG PET/CT in oncological patients undergoing immunotherapy, with special focus on response assessment in solid tumors.

METHODS

In a cooperative effort between the EANM, the SNMMI and the ANZSNM, clinical indications, recommended imaging procedures and reporting standards have been agreed upon and summarized in this joint guideline/procedure standard.

CONCLUSIONS

The field of immuno-oncology is rapidly evolving, and this guideline/procedure standard should not be seen as definitive, but rather as a guidance document standardizing the use and interpretation of [18F]FDG PET/CT during immunotherapy. Local variations to this guideline should be taken into consideration.

PREAMBLE

The European Association of Nuclear Medicine (EANM) is a professional non-profit medical association founded in 1985 to facilitate worldwide communication among individuals pursuing clinical and academic excellence in nuclear medicine. The Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote science, technology and practical application of nuclear medicine. The Australian and New Zealand Society of Nuclear Medicine (ANZSNM), founded in 1969, represents the major professional society fostering the technical and professional development of nuclear medicine practice across Australia and New Zealand. It promotes excellence in the nuclear medicine profession through education, research and a commitment to the highest professional standards. EANM, SNMMI and ANZSNM members are physicians, technologists, physicists and scientists specialized in the research and clinical practice of nuclear medicine. All three societies will periodically put forth new standards/guidelines for nuclear medicine practice to help advance the science of nuclear medicine and improve service to patients. Existing standards/guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each standard/guideline, representing a policy statement by the EANM/SNMMI/ANZSNM, has undergone a thorough consensus process, entailing extensive review. These societies recognize that the safe and effective use of diagnostic nuclear medicine imaging requires particular training and skills, as described in each document. These standards/guidelines are educational tools designed to assist practitioners in providing appropriate and effective nuclear medicine care for patients. These guidelines are consensus documents based on current knowledge. They are not intended to be inflexible rules or requirements of practice, nor should they be used to establish a legal standard of care. For these reasons and those set forth below, the EANM, SNMMI and ANZSNM caution against the use of these standards/guidelines in litigation in which the clinical decisions of a practitioner are called into question. The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by medical professionals considering the unique circumstances of each case. Thus, there is no implication that an action differing from what is laid out in the guidelines/procedure standards, standing alone, is below standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the standards/guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources or advances in knowledge or technology subsequent to publication of the guidelines/procedure standards. The practice of medicine involves not only the science, but also the art of dealing with the prevention, diagnosis, alleviation and treatment of disease. The variety and complexity of human conditions make it impossible for general guidelines to consistently allow for an accurate diagnosis to be reached or a particular treatment response to be predicted. Therefore, it should be recognized that adherence to these standards/ guidelines will not ensure a successful outcome. All that should be expected is that practitioners follow a reasonable course of action, based on their level of training, current knowledge, clinical practice guidelines, available resources and the needs/context of the patient being treated. The sole purpose of these guidelines is to assist practitioners in achieving this objective. The present guideline/procedure standard was developed collaboratively by the EANM, the SNMMI and the ANZSNM, with the support of international experts in the field. They summarize also the views of the Oncology and Theranostics and the Inflammation and Infection Committees of the EANM, as well as the procedure standards committee of the SNMMI, and reflect recommendations for which the EANM and SNMMI cannot be held responsible. The recommendations should be taken into the context of good practice of nuclear medicine and do not substitute for national and international legal or regulatory provisions.

ENETS standardized (synoptic) reporting for molecular imaging studies in neuroendocrine tumours

The European Neuroendocrine Tumor Society (ENETS) promotes practices and procedures that aim to improve the standard of care delivered to patients diagnosed with or suspected of having neuroendocrine neoplasia (NEN). At its annual Scientific Advisory Board Meeting in 2018, experts in imaging, pathology and clinical care of patients with NEN drafted guidance for the standardised reporting of diagnostic studies critical to the diagnosis, grading, staging and treatment of NEN. These included pathology, radiology, endoscopy and molecular imaging procedures. In an iterative process, a synoptic reporting template for molecular imaging procedures was developed to guide personalised therapies. Following pilot implementation and refinement within the ENETS Center of Excellence network, harmonisation with specialist imaging societies including the Society of Nuclear Medicine, European Association of Nuclear Medicine and the International Cancer Imaging Society will be pursued.

Incidence, prevalence, and survival trends for neuroendocrine neoplasms in Victoria, Australia, from 1982 to 2019: Based on site, grade, and region

AIMS

Neuroendorcine neoplasms (NENs) are rare tumors characterised by variable biology and delayed diagnosis. Several population studies have reported a marked increased incidence over time. The objectives of this analysis were to describe within Victoria (the second largest Australian state, 6.4 Million) the trends for NENs incidence/survival over nearly 38 years (1982-2019), and regional differences in survival.

METHODS

All NEN cases were identified from the Victorian Cancer Registry over four time periods: 1982-1989, 1990-1999, 2000-2009, and 2010-2019. Data collected included primary tumor site, histological grade, gender, overall survival (OS), and place of residence. Incidence data were analyzed with the generation of annual standardized rates (ASR). OS was assessed for the entire cohort and between geographical regions.

RESULTS

The overall NEN population (1982-2019) included 8,106 patients: over 60% grade 1/2 NENs, especially small bowel and colorectal. The number of new diagnoses increased over three-fold over time for the overall cohort and by tumoral categories. The ASR increased similarly, especially pancreatic NENs (4.3-fold) and differed between genders. The 5-year OS rates and median OS increased over time for the overall cohort: from 52% to 67% (p < 0.001). OS was greater for NEN patients residing in major cities relative to regional/remote areas (p = 0.01).

CONCLUSION

This population-wide analysis with over 38 years of data has confirmed the international trends of the increased incidence, prevalence, and OS of NEN patients regardless of primary site or histological grade. The analysis also observed a difference in survival outcome in rural/remote versus urban areas.

Surveillance imaging with FDG-PET/CT in the post-operative follow-up of stage 3 melanoma

Background

As early detection of recurrent melanoma maximizes treatment options, patients usually undergo post-operative imaging surveillance, increasingly with FDG-PET/CT (PET). To assess this, we evaluated stage 3 melanoma patients who underwent prospectively applied and sub-stage-specific schedules of PET surveillance.

Patients and methods

From 2009, patients with stage 3 melanoma routinely underwent PET +/- MRI brain scans via defined schedules based on sub-stage-specific relapse probabilities. Data were collected regarding patient characteristics and outcomes. Contingency analyses were carried out of imaging outcomes.

Results

One hundred and seventy patients (stage 3A: 34; 3B: 93; 3C: 43) underwent radiological surveillance. Relapses were identified in 65 (38%) patients, of which 45 (69%) were asymptomatic. False-positive imaging findings occurred in 7%, and 6% had treatable second (non-melanoma) malignancies. Positive predictive values (PPV) of individual scans were 56%-83%. Negative scans had predictive values of 89%-96% for true non-recurrence [negative predictive values (NPV)] until the next scan. A negative PET at 18 months had NPVs of 80%-84% for true non-recurrence at any time in the 47-month (median) follow-up period. Sensitivity and specificity of the overall approach of sub-stage-specific PET surveillance were 70% and 87%, respectively. Of relapsed patients, 33 (52%) underwent potentially curative resection and 10 (16%) remained disease-free after 24 months (median).

Conclusions

Application of sub-stage-specific PET in stage 3 melanoma enables asymptomatic detection of most recurrences, has high NPVs that may provide patient reassurance, and is associated with a high rate of detection of resectable and potentially curable disease at relapse.

Prediction and monitoring of relapse in stage III melanoma using circulating tumor DNA

BACKGROUND

The advent of effective adjuvant therapies for patients with resected melanoma has highlighted the need to stratify patients based on risk of relapse given the cost and toxicities associated with treatment. Here we assessed circulating tumor DNA (ctDNA) to predict and monitor relapse in resected stage III melanoma.

PATIENTS AND METHODS

Somatic mutations were identified in 99/133 (74%) patients through tumor tissue sequencing. Personalized droplet digital PCR (ddPCR) assays were used to detect known mutations in 315 prospectively collected plasma samples from mutation-positive patients. External validation was performed in a prospective independent cohort (n = 29).

RESULTS

ctDNA was detected in 37 of 99 (37%) individuals. In 81 patients who did not receive adjuvant therapy, 90% of patients with ctDNA detected at baseline and 100% of patients with ctDNA detected at the postoperative timepoint relapsed at a median follow up of 20 months. ctDNA detection predicted patients at high risk of relapse at baseline [relapse-free survival (RFS) hazard ratio (HR) 2.9; 95% confidence interval (CI) 1.5-5.6; P = 0.002] and postoperatively (HR 10; 95% CI 4.3-24; P < 0.001). ctDNA detection at baseline [HR 2.9; 95% CI 1.3-5.7; P = 0.003 and postoperatively (HR 11; 95% CI 4.3-27; P < 0.001] was also associated with inferior distant metastasis-free survival (DMFS). These findings were validated in the independent cohort. ctDNA detection remained an independent predictor of RFS and DMFS in multivariate analyses after adjustment for disease stage and BRAF mutation status.

CONCLUSION

Baseline and postoperative ctDNA detection in two independent prospective cohorts identified stage III melanoma patients at highest risk of relapse and has potential to inform adjuvant therapy decisions.

A pilot study of cardiopulmonary exercise testing and cardiac stress positron emission tomography before major non-cardiac surgery

Cardiac events are a common cause of peri-operative morbidity. Cardiopulmonary exercise testing can objectively assess risk, but it does not quantify myocardial ischaemia. With appropriate dietary preparation to suppress basal myocardial glucose uptake, positron emission tomography with ¹⁸ F-fluorodeoxyglucose can identify post-ischaemic myocardium, providing an attractive complement to exercise testing. We aimed to investigate the feasibility of this diagnostic algorithm. Patients referred for cardiopulmonary exercise testing before major cancer surgery were prospectively recruited. Exercise testing and positron emission tomography imaging were performed after a high fat-low carbohydrate meal. Protocol feasibility (primary end-point) included compliance with pre-test diet instructions and the completion of tests. Stress myocardial perfusion imaging was performed if either exercise testing or positron emission tomography was equivocal or positive for ischaemia. We recorded cardiac complications for 30 postoperative days. We enrolled 26 participants, 20 of whom completed protocol. Twenty-one participants proceeded to surgery: myocardial injury or infarction was diagnosed in three participants, two of whom had positive or equivocal positron emission tomography but negative myocardial perfusion imaging. We have shown that pre-operative cardiac positron emission tomography after cardiopulmonary exercise testing is feasible; protocol deviations were minor and did not affect image quality. Our findings warrant further investigation to compare the diagnostic utility of cardiac positron emission tomography imaging with standard pre-operative stress tests.

FDG PET/CT imaging in detecting and guiding management of invasive fungal infections: a retrospective comparison to conventional CT imaging

PURPOSE

Invasive fungal infections (IFIs) are common in immunocompromised patients. While early diagnosis can reduce otherwise high morbidity and mortality, conventional CT has suboptimal sensitivity and specificity. Small studies have suggested that the use of FDG PET/CT may improve the ability to detect IFI. The objective of this study was to describe the proven and probable IFIs detected on FDG PET/CT at our centre and compare the performance with that of CT for localization of infection, dissemination and response to therapy.

METHODS

FDG PET/CT reports for adults investigated at Peter MacCallum Cancer Centre were searched using keywords suggestive of fungal infection. Chart review was performed to describe the risk factors, type and location of IFIs, indication for FDG PET/CT, and comparison with CT for the detection of infection, and its dissemination and response to treatment.

RESULTS

Between 2007 and 2017, 45 patients had 48 proven/probable IFIs diagnosed prior to or following FDG PET/CT. Overall 96% had a known malignancy with 78% being haematological. FDG PET/CT located clinically occult infection or dissemination to another organ in 40% and 38% of IFI patients, respectively. Of 40 patients who had both FDG PET/CT and CT, sites of IFI dissemination were detected in 35% and 5%, respectively (p < 0.001). Of 18 patents who had both FDG PET/CT and CT follow-up imaging, there were discordant findings between the two imaging modalities in 11 (61%), in whom normalization of FDG avidity of a lesion suggested resolution of active infection despite a residual lesion on CT.

CONCLUSION

FDG PET/CT was able to localize clinically occult infection and dissemination and was particularly helpful in demonstrating response to antifungal therapy.

Combined PET/MRI: from Status Quo to Status Go. Summary Report of the Fifth International Workshop on PET/MR Imaging; February 15-19, 2016; Tübingen, Germany

This article provides a collaborative perspective of the discussions and conclusions from the fifth international workshop of combined positron emission tomorgraphy (PET)/magnetic resonance imaging (MRI) that was held in Tübingen, Germany, from February 15 to 19, 2016. Specifically, we summarise the second part of the workshop made up of invited presentations from active researchers in the field of PET/MRI and associated fields augmented by round table discussions and dialogue boards with specific topics. This year, this included practical advice as to possible approaches to moving PET/MRI into clinical routine, the use of PET/MRI in brain receptor imaging, in assessing cardiovascular diseases, cancer, infection, and inflammatory diseases. To address perceived challenges still remaining to innovatively integrate PET and MRI system technologies, a dedicated round table session brought together key representatives from industry and academia who were engaged with either the conceptualisation or early adoption of hybrid PET/MRI systems. Discussions during the workshop highlighted that emerging unique applications of PET/MRI such as the ability to provide multi-parametric quantitative and visual information which will enable not only overall disease detection but also disease characterisation would eventually be regarded as compelling arguments for the adoption of PET/MR. However, as indicated by previous workshops, evidence in favour of this observation is only growing slowly, mainly due to the ongoing inability to pool data cohorts from independent trials as well as different systems and sites. The participants emphasised that moving from status quo to status go entails the need to adopt standardised imaging procedures and the readiness to act together prospectively across multiple PET/MRI sites and vendors.

A phase Ib/II translational study of sunitinib with neoadjuvant radiotherapy in soft-tissue sarcoma

Background:

Preoperative radiotherapy (RT) is commonly used to treat localised soft-tissue sarcomas (STS). Hypoxia is an important determinant of radioresistance. Whether antiangiogenic therapy can ‘normalise' tumour vasculature, thereby improving oxygenation, remains unknown.

Methods:

Two cohorts were prospectively enrolled. Cohort A evaluated the implications of hypoxia in STS, using the hypoxic tracer ¹⁸F-azomycin arabinoside (FAZA-PET). In cohort B, sunitinib was added to preoperative RT in a dose-finding phase 1b/2 design.

Results:

In cohort A, 13 out of 23 tumours were hypoxic (FAZA-PET), correlating with metabolic activity (r²=0.85; P<0.001). Two-year progression-free (PFS) and overall (OS) survival were 61% (95% CI: 0.44–0.84) and 87% (95% CI: 0.74–1.00), respectively. Hypoxia was associated with radioresistance (P=0.012), higher local recurrence (Hazard ratio (HR): 10.2; P=0.02), PFS (HR: 8.4; P=0.02), and OS (HR: 41.4; P<0.04). In Cohort B, seven patients received sunitinib at dose level (DL): 0 (50 mg per day for 2 weeks before RT; 25 mg per day during RT) and two patients received DL: −1 (37.5 mg per day for entire period). Dose-limiting toxicities were observed in 4 out of 7 patients at DL 0 and 2 out of 2 patients at DL −1, resulting in premature study closure. Although there was no difference in PFS or OS, patients receiving sunitinib had higher local failure (HR: 8.1; P=0.004).

Conclusion:

In STS, hypoxia is associated with adverse outcomes. The combination of sunitinib with preoperative RT resulted in unacceptable toxicities, and higher local relapse rates.

Limited role for surveillance PET-CT scanning in patients with diffuse large B-cell lymphoma in complete metabolic remission following primary therapy

Background:

The usefulness of positron emission tomography with computed tomography (PET–CT) in the surveillance of patients with diffuse large B-cell lymphoma (DLBCL) in complete metabolic remission after primary therapy is not well studied.

Methods:

We performed a retrospective review of our database between 2002 and 2009 for patients with de novo DLBCL who underwent surveillance PET–CT after achieving complete metabolic response (CMR) following primary therapy.

Results:

Four-hundred and fifty scans were performed in 116 patients, with a median follow-up of 53 (range 8–133) months from completion of therapy. Thirteen patients (11%) relapsed: seven were suspected clinically and six were subclinical (all within first 18 months). The positive predictive value in patients with international prognostic index (IPI) <3 was 56% compared with 80% in patients with IPI⩾3. Including indeterminate scans, PET–CT retained high sensitivity 95% and specificity 97% for relapse.

Conclusion:

Positron emission tomography with computed tomography is not useful in patients for the majority of patients with diffuse large B-cell lymphoma in CMR after primary therapy, with the possible exception of patients with baseline IPI ⩾3 in the 18 months following completion of primary therapy. This issue could be addressed by a prospective clinical trial.

Role of FDG-PET/CT in staging and follow-up of head and neck squamous cell carcinoma

The established and emerging roles of FDG positron-emission tomography/computed tomography (PET/CT) in the evaluation of squamous cell carcinoma of head and neck region is reviewed with a strong clinical focus on recommended applications and methodologies. In the staging of newly diagnosed disease, detection of cervical nodal involvement is the major indication but exclusion of distant metastases and of synchronous primary malignancy is also a valuable adjunct. Use in radiotherapy planning is advantageous for locally-advanced disease. Although there are few data yet to assess the use of FDG PET/CT to assess response during therapy, there is good evidence that this technique can accurately assess the post-treatment neck to identify those who might benefit from salvage therapy and those in whom observation or palliative treatment might be more appropriate. Although more expensive than other imaging modalities used for assessing this disease, the superior diagnostic accuracy and impact of incremental information provided by this technology has been shown to be cost-effective in several clinical scenarios.

Imaging in follicular NHL

Imaging contributes to management of follicular lymphoma (FL) through guiding biopsy, determining disease stage and assessing therapeutic response. Molecular imaging with positron emission tomography (PET), especially when combined with computer tomography (PET/CT), is more accurate than conventional imaging and extends the role of imaging to lesion characterisation, including non-invasive assessment of high-grade transformation. There is strong data to support the use of FDG PET/CT for primary staging, resulting in significant management change. In patients with early stage follicular lymphoma (stage I or II), there is a clear role for PET/CT to avoid futile involved-field radiotherapy in patients with widespread disease and to optimise the treatment field in patients with confirmed localised disease. For restaging, use of PET/CT allows discrimination between scar tissue and viable tumour in residual masses. Molecular imaging is likely to play an increasing role in selection of patients for specific treatments and in prognostic stratification.

Metabolic response of rectal cancer assessed by 18-FDG PET following chemoradiotherapy is prognostic for patient outcome

BACKGROUND

Complete pathological response has proven prognostic benefits in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy. Sequential 18-FDG PET may be an early surrogate for pathological response to chemoradiotherapy.

OBJECTIVES

The aim of this study was to identify whether metabolic response measured by FDG PET following chemoradiotherapy is prognostic for tumor recurrence and survival following neoadjuvant therapy and surgical treatment for primary rectal cancer.

METHODS

Patients with primary rectal cancer treated by long-course neoadjuvant chemoradiotherapy followed by surgery had FDG PET performed before and 4 weeks after treatment, before surgical resection was performed. Retrospective chart review was undertaken for patient demographics, tumor staging, recurrence rates, and survival.

RESULTS

: Between 2000 and 2007, 78 patients were identified (53 male, 25 female; median age, 64 y). After chemoradiotherapy, 37 patients (47%) had a complete metabolic response, 26 (33%) had a partial metabolic response, and 14 (18%) had no metabolic response as assessed by FDG PET (1 patient had missing data). However, only 4 patients (5%) had a complete pathological response. The median postoperative follow-up period was 3.1 years during which 14 patients (19%) had a recurrence: 2 local, 9 distant, and 3 with both local and distant. The estimated percentage without recurrence was 77% at 5 years (95% CI 66%-89%). There was an inverse relationship between FDG PET metabolic response and the incidence of recurrence within 3 years (P = .04). Kaplan-Meier analysis of FDG PET metabolic response and overall survival demonstrated a significant difference in survival among patients in the 3 arms: complete, partial, and no metabolic response (P = .04); the patients with complete metabolic response had the best prognosis.

CONCLUSION

Complete or partial metabolic response on PET following neoadjuvant chemoradiotherapy and surgery predicts a lower local recurrence rate and improved survival compared with patients with no metabolic response. Metabolic response may be used to stratify prognosis in patients with rectal cancer.

Impact of 18F-fluorodeoxyglucose positron emission tomography in the staging and treatment response assessment of extra-pulmonary small-cell cancer

The aim of this study was to retrospectively evaluate the value of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in extrapulmonary small-cell cancer (EPSCC). Patients with EPSCC who underwent PET for staging or response assessment between 1996 and 2007 were identified from a database. Patient records were reviewed. PET-based, and conventional staging and restaging results were compared. The binary staging classification of limited disease (LD) versus extensive disease (ED) was used. Patients with LD had tumours that could be encompassed within a tolerable radiation therapy (RT) volume. Of 33 eligible patients, 12 had staging PET scans, 11 had restaging scans and 10 had both. All known gross disease sites were FDG-avid. PET and conventional stage groupings were concordant in 21 of 22 cases. One patient was appropriately upstaged from LD to ED by PET. PET detected additional disease sites, without causing upstaging in three further patients. Restaging PET scans identified previously unrecognised persistent or progressive disease in 4 of 21 cases. In four further cases, persistent FDG uptake after treatment was either false positive (n = 2) or of uncertain (n = 2) aetiology. PPV was 100% for staging and 82% for restaging. In 8 of 43 imaging episodes (19%), PET appropriately influenced management in five cases by changing treatment intent from radical to palliative, and in three cases by altering the RT volume. PET has incremental value compared to conventional imaging for staging EPSCC, and may also be useful for restaging after therapy. PET influenced patient management in 19% of 43 imaging episodes.

Use of molecular targeted agents for the diagnosis, staging and therapy of neuroendocrine malignancy

Imaging of neuroendocrine tumours (NET) poses significant challenges because of the heterogeneous biology of the tumours that are represented by this class of neoplasia. NET can range from benign lesions to highly aggressive cancers. Structural imaging techniques have suboptimal sensitivity in most published series and diagnosis is often delayed until metastatic disease is present. Current guidelines emphasise the importance of functional imaging for evaluating the extent of NET. The mainstay of this type of imaging has been somatostatin receptor scintigraphy (SRS) with [¹¹¹In]diethylenetriaminepentaacetic acid-octreotide (Octreoscan™). Routine use of single-photon emission computed tomography (SPECT) and particularly of hybrid SPECT/computed tomography (CT) has significantly improved localisation of tumour sites and evaluation of somatostatin receptor (SSTR) expression, which is important for predicting the likelihood of response to somatostatin analogues (SSA). Positron emission tomography (PET) can also now be used for evaluating SSTR expression. There are a number of peptides that have been evaluated but [⁶⁸Ga]tetraazocyclodecanetetraacetic acid (DOTA)-octreotate (GaTate) PET/CT, which has been shown to be significantly more sensitive for detecting small lesions than Octreoscan™, is now probably the preferred agent because high uptake in known sites of disease provides a diagnostic pair for assessing suitability of patients for [¹⁷⁷Lu]DOTA-octreotate (LuTate) peptide receptor radionuclide therapy (PRRT). A range of other radiolabelled SSA has also been used for PRRT. Lesions without SSTR expression require alternative imaging and therapeutic strategies. Although fluorodeoxyglucose (FDG) uptake in low-grade NET is not generally increased relative to normal tissues, the loss of differentiation that often accompanies loss of SSTR expression may be associated with a significant increase in glycolytic metabolism and an accompanying improvement in the diagnostic sensitivity of FDG PET/CT. High FDG avidity is associated with a poorer prognosis but increases the likelihood of response to chemotherapy. Functioning tumours also require substrates for their secreted products. This can be exploited for NET imaging with amine precursor uptake being imaged using [¹⁸F]3,4-dihydrophenylalanine and serotonin-secreting tumours being sensitively detected using [¹¹C]5-hydroxytryptamine. Both these agents are suitable for imaging with PET. [¹²³I]meta-Iodo-benzyl-guanidine (MIBG) SPECT/CT may also be useful as a staging technique, particularly for NET of the sympathetic neuronal chain, and can identify patients who may be suitable for [¹³¹I]MIBG therapy. In the future, paradigms guided by clinical and biopsy features should allow personalised imaging paradigms aligned to therapeutic options.

Endoscopic ultrasound-guided fine-needle aspiration when combined with positron emission tomography improves specificity and overall diagnostic accuracy in unexplained mediastinal lymphadenopathy and staging of non-small-cell lung cancer

BACKGROUND

The aim of this study was to assess the incremental value of endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) to positron emission tomography (PET) in the diagnosis of unexplained mediastinal lymphadenopathy and staging of non-small-cell lung cancer (NSCLC).

METHODS

Patients who had both EUS-guided FNA and PET were retrospectively identified from an EUS database at a tertiary hospital. All EUS-guided FNA were carried out by one endoscopist between August 2002 and April 2005, either for the diagnosis of unexplained mediastinal lymphadenopathy or for the staging of NSCLC. Results of PET and EUS were compared with histology. A true histological positive result was defined as histological involvement in either surgery (mediastinoscopy or resection) or EUS-guided FNA. A true histological negative result was defined as negative involvement at surgery (mediastinoscopy or resection).

RESULTS

Forty-nine patients who had both PET scanning and EUS-guided FNA for diagnosis of unexplained mediastinal lymphadenopathy or staging of NSCLC were identified. Of these, 33 (73% males, n = 24, age range = 44-78 years, mean = 62 years) had surgical confirmation of mediastinal lymph node pathology. In these patients, PET alone showed sensitivity, 95%; specificity, 90%; positive predictive value, 87%; negative predictive value, 90% and accuracy, 88%; whereas the addition of EUS-guided FNA increased the overall specificity and positive predictive value to 100%, with an overall accuracy of 97%.

CONCLUSIONS

This study suggests that EUS-guided FNA complements PET by improving the overall specificity and thereby the accuracy for diagnosis of unexplained mediastinal lymphadenopathy. It provides a minimally invasive technique to assess the mediastinum in patients with NSCLC and is particularly valuable in cases in which PET findings are equivocal.

Evaluation of pulmonary nodules and lung cancer with one-inch crystal gamma coincidence positron emission tomography/CT versus dedicated positron emission tomography/CT

Dedicated positron emission tomography (PET)/CT scanners using BGO and related detectors (d-PET) have become standard imaging instruments in many malignancies. Hybrid gamma camera systems using NaI detectors in coincidence mode (g-PET) have been compared to d-PET but reported usefulness has been variable when gamma cameras with half-inch to three-fourth-inch thick crystals have been used without CT. Our aim was to compare g-PET with a 1-in.-thick crystal and inbuilt CT for lesion localization and attenuation correction (g-PET/CT) and d-PET/CT in patients presenting with potential and confirmed lung malignancies. One hour after (18)F-fluorodeoxyglucose (FDG), patients underwent BGO d-PET/CT from jaw to proximal thigh. This was followed by one to two bed position g-PET/CT 194 +/- 27 min after FDG. Each study pair was independently analysed with concurrent CT. d-PET/CT was interpreted by a radiologist experienced in both PET and CT, and g-PET/CT by consensus reading of an experienced PET physician and an experienced CT radiologist. A TNM score was assigned and studies were then unblinded and compared. Fifty-seven patients underwent 58 scan pairs over 2 years. Eighty-nine per cent concordance was shown between g-PET/CT and d-PET/CT for the assessment of intrapulmonary lesions, with 100% concordance for intrapulmonary lesions >10 mm (36 of 36). Eighty-eight per cent (51 of 58) concordance was shown between g-PET/CT and d-PET/CT for TNM staging. Coincidence imaging using an optimized dual-head 1-in.-thick crystal gamma camera with inbuilt CT compares reasonably well with dedicated PET/CT for evaluation of indeterminate pulmonary lesions and staging of pulmonary malignancies and may be of some value when d-PET/CT is not readily available.

Primary skeletal muscle marginal zone lymphoma with persistent tissue tropism and PET-avidity

This study describes a case of extra-nodal marginal zone lymphoma presenting in skeletal muscle and recurring on multiple occasions in the same tissue at other sites. In this case, 18F-fluoro-deoxy-glucose positron emission tomography scanning was the most useful surveillance modality.

The impact of PET-CT in suspected recurrent ovarian cancer: A prospective multi-centre study as part of the Australian PET Data Collection Project

OBJECTIVE

To assess the impact of FDG PET-CT on the management of patients with suspected recurrent ovarian cancer and to determine the incremental information provided by PET-CT.

METHODS

This was a prospective, multi-centre, cohort study. Ninety women (mean age 59.9 years; age range 35-85 years) with a previous history of treated epithelial ovarian carcinoma and suspected recurrence based on elevated CA-125, anatomical imaging or clinical symptoms were studied with FDG PET-CT across two States. Referring doctors were asked to specify a management plan pre-PET, if management was altered after PET-CT and, the impact (rated - none, low, medium, high) of PET-CT on patient management. The pre-PET management plan could include radiotherapy, chemotherapy, surgery, and 'other' including observation. Patients were followed at 6 and 12 months and clinical status, evidence of recurrence and progression were recorded.

RESULTS

Patients were referred by 34 individual specialists. At least 168 additional sites of disease in 61 patients (68%), not identified by conventional imaging were identified by PET-CT. In 77% the additional lesions were located below the diaphragm and most were nodal or peritoneal. PET-CT affected management in 60% (49% high, 11% medium impact). Patients where more disease was detected with PET-CT were more likely to progress in the following 12 months.

CONCLUSIONS

For women with previously treated ovarian carcinoma with recurrent disease, PET-CT can: a) alter management in close to 60% of patients, b) detect more sites of disease than abdominal and pelvic CT, c) is superior in the detection of nodal, peritoneal and subcapsular liver disease and d) offers the opportunity for technology replacement in this setting.

Comparison of CT and positron emission tomography/CT coregistered images in planning radical radiotherapy in patients with non-small-cell lung cancer

Imaging with F-18 fluorodeoxyglucose positron emission tomography (PET) significantly improves lung cancer staging, especially when PET and CT information are combined. We describe a method for obtaining CT and PET images at separate acquisitions, which allows coregistration and incorporation of PET information into the radiotherapy (RT) planning process for non-small-cell lung cancer. The influence of PET information on RT planning was analysed for 10 consecutive patients. Computed tomography and PET images were acquired with the patient in an immobilization device, in the treatment position. Using specially written software, PET and CT data were coregistered using fiducial markers and imported into our RT planning system (Cadplan version 6). Treatment plans were prepared with and without access to PET/CT coregistered images and then compared. PET influenced the treatment plan in all cases. In three cases, geographic misses (gross tumour outside planning target volume) would have occurred had PET not been used. In a further three cases, better planning target volume marginal coverage was achieved with PET. In four patients, three with atelectasis, there were significant reductions in V20 (percentage of the total lung volume receiving 20 Gy or more). Use of coregistered PET/CT images significantly altered treatment plans in a majority of cases. This method could be used in routine practice at centres without access to a combined PET/CT scanner .

Phenolic Michael Reaction Acceptors: Combined Direct and Indirect Antioxidant Defenses Against Electrophiles and Oxidants

The implications of oxidative stress in the pathogenesis of many chronic human diseases has led to the widely accepted view that low molecular weight antioxidants could be beneficial and postpone or even prevent these diseases. Small molecules of either plant or synthetic origins, which contain Michael acceptor functionalities (olefins or acetylenes conjugated to electron-withdrawing groups) protect against the toxicity of oxidants and electrophiles indirectly, i.e., by inducing phase 2 cytoprotective enzymes. Some of these molecules, e.g., flavonoid and curcuminoid analogues that have phenolic hydroxyl groups in addition to Michael acceptor centers, are also potent direct antioxidants, and may therefore be appropriately designated: bifunctional antioxidants. By use of spectroscopic methods we identified phenolic chalcone and bis(benzylidene)acetone analogues containing one or two Michael acceptor groups, respectively, as very efficient scavengers of two different types of radicals: (a) the nitrogen-centered 2,2'-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS.+) radical cation, and (b) the oxygen-centered galvinoxyl (phenoxyl) radical. The most potent scavengers are those also bearing hydroxyl substituents on the aromatic ring(s) at the ortho-position(s). The initial reaction velocities are very rapid and concentration-dependent. In the human keratinocyte cell line HaCaT, the same compounds coordinately increase the intracellular levels of glutathione, glutathione reductase, and thioredoxin reductase. Thus, such bifunctional antioxidants could exert synergistic protective effects against oxidants and electrophiles which represent the principal biological hazards by: (i) scavenging hazardous oxidants directly and immediately; and (ii) inducing the phase 2 response to prevent and resolve the consequences of hazardous processes that are already in progress, i.e., acting indirectly, but with much more diverse and long-lasting effects.

"Magnetic resonance imaging negative positron emission tomography positive" temporal lobe epilepsy: FDG-PET pattern differs from mesial temporal lobe epilepsy

PURPOSE

Some patients with temporal lobe epilepsy (TLE) lack evidence of hippocampal sclerosis (HS) on MRI (HS-ve). We hypothesized that this group would have a different pattern of 2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET) hypometabolism than typical mesial TLE/HS patients with evidence of hippocampal atrophy on magnetic resonance imaging (MRI) (HS+ve), with a lateral temporal neocortical rather than mesial focus.

PROCEDURES

Thirty consecutive HS-ve patients and 30 age- and sex-matched HS+ve patients with well-lateralized EEG were identified. FDG-PET was performed on 28 HS-ve patients and 24 HS+ve patients. Both groups were compared using statistical parametric mapping (SPM), directly and with FDG-PET from 20 healthy controls.

RESULTS

Both groups showed lateralized temporal hypometabolism compared to controls. In HS+ve, this was antero-infero-mesial (T = 17.13); in HS-ve the main clustering was inferolateral (T = 17.63). When directly compared, HS+ve had greater hypometabolism inmesial temporal/hippocampal regions (T = 4.86); HS-ve had greater inferolateral temporal hypometabolism (T = 4.18).

CONCLUSIONS

These data support the hypothesis that focal hypometabolism involves primarily lateal neocortical rather than mesial temporal structures in 'MRI-negative PET-positive TLE.'

In vivo tracking of macrophage activated killer cells to sites of metastatic ovarian carcinoma

Radio-labelling of blood cells is an established technique for evaluating in vivo migration of normal cells to sites of pathology such as infection and haemorrhage. A limitation of cellular immunotherapies to induce anti-tumour responses is in part due to the uncertain ability of cellular effectors to reach their intended target. We extended the approach of cell radiolabelling to accurately examine the in vivo distribution of cellular immunotherapy with ex-vivo macrophage activated killer (MAK) cells. We describe the use of two methods of cell labelling for tracking the destination of autologous-derived macrophage activated killer (MAK) cells linked to the bi-specific antibody MDX-H210 delivered either by intravenous (i.v.) or intraperitoneal (i.p.) injection in ten patients with peritoneal relapse of epithelial ovarian carcinoma. Our results demonstrate the feasibility of generating high numbers and purity of GMP quality MAK cells, which can be radiolabelled with (18)F-FDG or (111)In-oxime. MAK cell administration produced minimal infusional toxicity and demonstrated a reproducible pattern of in vivo distribution and active in vivo tracking to sites of known tumour following 8 of 16 i.v. infusions or 4 of 6 i.p. infusions. However, the leakage of (18)F-FDG limited the ability to confidently confirm the tracking of MAK cells to tumour in all cases and improved PET labels are required. The addition of MDX-H210 bispecific antibody did not alter the distribution of cells to tumour sites, but did accelerate the clearance of i.v. administered MAK cells from the pulmonary circulation. This data demonstrates that cellular cancer immunotherapies may be successfully delivered to the sites of active tumour following either i.v. or i.p. injection in a proportion of patients with metastatic cancer. Incorporation of tracking studies in early cycles of cellular immunotherapy may allow selection of patients who demonstrate successful targeting of the immunotherapy for ongoing treatment.

Positron emission tomography of stage IV mucosa-associated lymphoid tissue lymphoma confined to the four major salivary glands

In a patient with stage IVA marginal zone lymphoma, (18)F-fluorodeoxyglucose-positron emission tomography indicated that the disease was confined to the four major salivary glands. The positron emission tomography findings encouraged the use of radiotherapy with curative intent in this case. After 30 Gy of external beam radiotherapy to the parotid and submandibular glands, the patient entered a complete remission and remains free from progression more than 4 years later.

Management of paediatric thyroid carcinoma: recent experience with recombinant human thyroid stimulating hormone in preparation for radioiodine therapy

BACKGROUND

Thyroid carcinoma in children is rare and raises unique management issues. Although metastatic disease is more common in this age group, prognosis remains good with appropriate treatment. The aim of the study was to report recent experience in the management of differentiated thyroid carcinoma in children, especially in the use of radioiodine after recombinant human thyroid stimulating hormone (rhTSH) stimulation.

METHODS

Eight patients, aged 5-17 years (five were boys) presented following total thyroidectomy for thyroid carcinoma between May 2003 and June 2005. Seven had papillary carcinoma and one had follicular carcinoma. Five had known lymph node metastases and one had pulmonary metastases at presentation. Four patients had previously received therapeutic irradiation for malignancy. All eight underwent diagnostic iodine scans, seven with rhTSH stimulation. Seven went on to receive radioiodine treatment as hospital inpatients, comanaged by the paediatric and nuclear medicine units. The dosage of 131I ranged from 1.5 to 3.7 x 10(9) Bq. All except one were prepared by rhTSH stimulation.

RESULTS

Seven of eight patients had significant uptake in the neck on diagnostic scan and two had pulmonary abnormalities. Six of seven evaluable patients achieved complete thyroid ablation. Both patients with pulmonary abnormalities had scan resolution, although one of them only after a second radioiodine treatment. All patients had thyroxine replacement in doses to suppress TSH and all remain alive and well at time of carrying out this study.

CONCLUSION

Optimal management of paediatric thyroid carcinoma necessitates a multidisciplinary approach. Radioiodine therapy under rhTSH is an effective and safe adjuvant treatment in this special subgroup.

Imaging with FLT-PET demonstrates that PF-477736, an inhibitor of CHK1 kinase, overcomes a cell cycle checkpoint induced by gemcitabine in PC-3 xenografts

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Background: The development of strategies to monitor the molecular and cellular response to novel agents that target the cell cycle is vital to provide proof of mechanism and biological activity of these compounds. The protein kinase CHK1 is activated following DNA damage in the S and G2-phases of the cell cycle and mediates cell cycle arrest. In vitro studies demonstrate that inhibition of CHK1 can overcome cell cycle arrest induced by DNA damage and enhance cytotoxic activity of DNA damaging agents. In vivo studies show that combining DNA damaging agents with a CHK1 inhibitor potentiates antitumor activity. We hypothesize that functional imaging with 18F-fluorine-L-thymidine (FLT), a PET-tracer where tumor uptake is maximal in the S and G2 phases of the cell cycle can be used to non-invasively monitor the induction and therapeutic inhibition of a cell cycle checkpoint in vivo. Methods: Nude mice harbouring PC-3 xenografts were treated with vehicle controls, gemcitabine, the CHK1-inhibitor PF-477736 or gemcitabine + PF-477736. FLT-PET scans were performed and tumors harvested for ex-vivo biomarkers to assess S-phase, M-phase and DNA-repair. Results: Gemcitabine induced a 8.3 ±0.8 fold increase in tumoral uptake of FLT at 21 hours that correlated with a 3.3 ±0.2-fold increase in thymidine kinase activity and S-phase arrest as demonstrated by BrdU incorporation and elevated expression of cyclin-A. Treatment with PF-477736 at 17 hours after gemcitabine abrogated the early FLT-flare at 21 hours by 82% (p<0.001). This was associated with both an increased fraction of cells in mitosis and G1-phase of the cell cycle as determined by phos-histone H3 and flow cytometry. Furthermore, the combination of gemcitabine and PF-477736 enhanced DNA damage as measured by phos-gamma-H2AX and significantly delayed tumor growth when compared to tumors treated with gemcitabine alone. Conclusion: These data clearly indicate that the CHK1-inhibitor PF-477736 can overcome the cell cycle checkpoint induced by gemcitabine and increase associated DNA damage in tumors in-vivo. The PET studies indicate that functional imaging with FLT-PET is a promising strategy to monitor responses to therapeutic agents that target cell cycle checkpoints.

[Table: see text]

In vivo tracking for cell therapies

The success of a particular cellular therapy regime requires the therapeutic agent to migrate expeditiously to the intended target in sufficient numbers and to provoke a desirable response. There are many variables associated with the production, administration and host that need to be investigated to maximize the resulting therapeutic benefit. The large number of factors which may contribute to, or detract from, treatment efficacy can make therapy optimization an arduous procedure. Direct visualization of in vivo migration patterns using nuclear medicine techniques greatly assists the appraisal of the multitude of variables. Conventional radionuclide cell labeling is a proven, simple and sensitive technique which can provide whole body biodistribution information. Labeling with a PET isotope offers greater sensitivity, much improved 3-dimensional resolution and quantification. In general, current efforts are increasingly concentrating on this technology. Imaging studies can supply definitive evidence of successful targeting and allow quantification of the degree of migration to a particular site. Incorporating tracking studies into clinical trials of cell-based therapy at the earliest stage can provide proof of mechanism of the therapy and permit evaluation of the many contributory variables, even on a patient-by-patient basis.

Oxaliplatin combined with infusional 5-fluorouracil and concomitant radiotherapy in inoperable and metastatic rectal cancer: a phase I trial

The aim of this study was to define the recommended dose of oxaliplatin when combined with infusional 5-fluorouracil (5-FU) and concurrent pelvic radiotherapy. Eligible patients had inoperable rectal cancer, or symptomatic primary rectal cancer with metastasis. Oxaliplatin was given on day 1 of weeks 1, 3 and 5 of radiotherapy. Dose level 1 was oxaliplatin 70 mg m(-2) with 5-FU 200 mg m(-2) day(-1) continuous infusion 96 h week(-1). On dose level 2, the oxaliplatin dose was increased to 85 mg m(-2). On dose level 3, the duration of the 5-FU was increased to 168 h per week. Pelvic radiotherapy was 45 Gray (Gy) in 25 fractions over 5 weeks with a boost of 5.4 Gy. Fluorine-18 fluoro deoxyglucose and Fluorine-18 fluoro misonidazole positron emission tomography (FDG-PET and FMISO-PET) were used to assess metabolic tumour response and hypoxia. In all, 16 patients were accrued. Dose-limiting toxicities occurred in one patient at level 2 (grade 3 chest infection), and two patients at level 3 (grade 3 diarrhoea). Dose level 2 was declared the recommended dose level. FDG-PET imaging showed metabolic responses in 11 of the 12 primary tumours assessed. Four of six tumours had detectable hypoxia on FMISO-PET scans. The addition of oxaliplatin to infusional 5-FU chemoradiotherapy was feasible and generally well tolerated. For future trials, oxaliplatin 85 mg m(-2) and 5-FU 200 mg m(-2) day(-1) continuous infusion 96 h week(-1) is the recommended dose when combined with 50.4 Gy of pelvic radiotherapy.

18F-fluorodeoxyglucose positron emission tomography in evaluation of germ cell tumor after chemotherapy

OBJECTIVES

To evaluate the role of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in the assessment of germ cell tumors after chemotherapy.

METHODS

We reviewed patients' records for the histologic findings and clinical outcome. 18F-FDG PET results were correlated with tissue histologic features where available; and if not available, the correlation was with the clinical outcome.

RESULTS

A total of 45 PET studies were performed on 38 patients (age range 19 to 64 years, median 31). All patients had received chemotherapy. In the nonseminomatous germ cell tumor (NSGCT) group, of the 31 patients with one scan, 18 PET scans were reported as positive, with only 2 not having active disease. Of the 12 negative scans, 6 showed teratoma, 1 tumor, and 5 did not show active disease. The equivocal scan revealed thyroid adenoma. In the seminoma group, the PET scans correlated well with the clinical and histologic outcomes. Four patients underwent salvage chemotherapy, and in this subgroup, the PET findings also correlated with the outcome.

CONCLUSIONS

(18)F-FDG PET is a promising tool as an adjunct to current imaging techniques in detecting residual viable germ cell tumor after chemotherapy. In NSGCT, a positive PET scan was accurate in 16 of 18 patients, although negative PET studies did not exclude the presence of disease, mainly because of the presence of teratoma. In seminoma, a negative 18F-FDG PET study correlated with a favorable clinical outcome. PET was also predictive of the response to salvage chemotherapy and was highly specific for active tumor in both NSGCT and seminoma.

MRI-negative PET-positive temporal lobe epilepsy: a distinct surgically remediable syndrome

Most patients with non-lesional temporal lobe epilepsy (NLTLE) will have the findings of hippocampal sclerosis (HS) on a high resolution MRI. However, a significant minority of patients with NLTLE and electroclinically well-lateralized temporal lobe seizures have no evidence of HS on MRI. Many of these patients have concordant hypometabolism on fluorodeoxyglucose-PET ([18F]FDG-PET). The pathophysiological basis of this latter group remains uncertain. We aimed to determine whether NLTLE without HS on MRI represents a variant of or a different clinicopathological syndrome from that of NLTLE with HS on MRI. The clinical, EEG, [18F]FDG-PET, histopathological and surgical outcomes of 30 consecutive NLTLE patients with well-lateralized EEG but without HS on MRI (HS-ve TLE) were compared with 30 consecutive age- and sex-matched NLTLE patients with well-lateralized EEG with HS on MRI (HS+ve TLE). Both the HS+ve TLE group and the HS-ve TLE patients had a high degree of [18F]FDG-PET concordant lateralization (26 out of 30 HS-ve TLE versus 27 out of 27 HS+ve TLE). HS-ve TLE patients had more widespread hypometabolism on [18F]FDG-PET by blinded visual analysis [odds ratio (OR = + infinity (2.51, -), P = 0.001]. The HS-ve TLE group less frequently had a history of febrile convulsions [OR = 0.077 (0.002-0.512), P = 0.002], more commonly had a delta rhythm at ictal onset [OR = 3.67 (0.97-20.47), P = 0.057], and less frequently had histopathological evidence of HS [OR = 0 (0-0.85), P = 0.031]. There was no significant difference in surgical outcome despite half of those without HS having a hippocampal-sparing procedure. Based on the findings outlined, HS-ve PET-positive TLE may be a surgically remediable syndrome distinct from HS+ve TLE, with a pathophysiological basis that primarily involves lateral temporal neocortical rather than mesial temporal structures.

Relation between FIGO stage, primary tumor volume, and presence of lymph node metastases in cervical cancer patients referred for radiotherapy

The aims of this study were to determine, firstly, the relationship between FIGO stage and various tumor parameters determined by magnetic resonance imaging (MRI), and, secondly, whether any of these parameters were predictors of lymph node metastases as determined by fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) in cervical cancer patients referred for radiotherapy. In 70 consecutive patients, both PET and MRI visualized all primary tumors except for one previously removed by cone biopsy. While clinical diameter and MRI-derived diameter showed a significant relationship between these two measurements (r = 0.70; P < 0.001) there was a large variability in MRI diameter for each FIGO stage and wide overlap. The average volume of primary cervical tumor on MRI was 60 cc (5-256). In FIGO stages, I, II, III and IV, uterine body involvement was present in 58%, 73%, 88%, and 100% of 19, 30, 16, and 5 patients, respectively (Ptrend= 0.015). Node positivity on FDG PET was present in 11% of patients without uterine body extension, but increased to 75% in those with uterine involvement. Average tumor volume in node-negative patients was 49 cc (5-186). Average tumor volume in node-positive patients was 69 cc (8-256). There was a significant association between nodal involvement and both FIGO stage (P = 0.018) and uterine body involvement (P < 0.001), but tumor volume and longitudinal MRI diameter were not statistically significant in unifactor predictors of nodal involvement. In multivariate analysis only uterine body extension, however, was independently related to the risk of nodal involvement. In conclusion, MRI provides noninvasive tumor size evaluation and can also demonstrate invasion of the uterine body that appears to be associated with an increased risk of nodal metastasis. This may provide clinically important prognostic information not available from current FIGO staging.

A comparison of fluorine-18 fluoro-deoxyglucose PET and technetium-99m sestamibi in assessing patients with multiple myeloma

OBJECTIVE

The extent of disease in patients with multiple myeloma or related conditions may be difficult to assess. In previous small studies, both FDG-PET (PET) and Tc-99m sestamibi scans (MIBI) have identified sites of occult disease in myeloma.

METHODS

We reviewed the results for patients at our institution who have undergone PET and/or MIBI scans to assess myeloma. Concordance between the scans, ability to identify otherwise occult disease and impact on patient management was assessed.

RESULTS

Thirty-six patients had > or =1 PET scan, 56 had > or =1 MIBI scan and 23 had concurrent PET and MIBI scans. MIBI detected additional sites to skeletal survey in 38 of 56 (68%) cases. PET detected additional sites to skeletal survey in 18 of 36 (50%) cases. MIBI generally detected more disease sites than PET. PET and MIBI were concordant in eight of 23 (35%) cases. The percentage plasma cell infiltrate within the marrow correlated with the number of sites detected by MIBI, but not by PET. In 23 of 69 cases (33%), scan results impacted on management, particularly by upstaging disease at diagnosis and by recognising subsequent disease progression. The results were also helpful for evaluating the presence of ongoing disease activity in previously irradiated sites remaining abnormal on skeletal survey following treatment.

CONCLUSIONS

MIBI and PET are useful additional diagnostic tools for detecting otherwise occult sites of myeloma. The use of MIBI PET should particularly be considered in the evaluation of a patient with an early-stage plasma cell dyscrasia to exclude the presence of more extensive disease.

Relation between FIGO stage, primary tumor volume, and presence of lymph node metastases in cervical cancer patients referred for radiotherapy

The aims of this study were to determine, firstly, the relationship between FIGO stage and various tumor parameters determined by magnetic resonance imaging (MRI), and, secondly, whether any of these parameters were predictors of lymph node metastases as determined by fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) in cervical cancer patients referred for radiotherapy. In 70 consecutive patients, both PET and MRI visualized all primary tumors except for one previously removed by cone biopsy. While clinical diameter and MRI-derived diameter showed a significant relationship between these two measurements (r = 0.70; P < 0.001) there was a large variability in MRI diameter for each FIGO stage and wide overlap. The average volume of primary cervical tumor on MRI was 60 cc (5–256). In FIGO stages, I, II, III and IV, uterine body involvement was present in 58%, 73%, 88%, and 100% of 19, 30, 16, and 5 patients, respectively (Ptrend = 0.015). Node positivity on FDG PET was present in 11% of patients without uterine body extension, but increased to 75% in those with uterine involvement. Average tumor volume in node-negative patients was 49 cc (5–186). Average tumor volume in node-positive patients was 69 cc (8–256). There was a significant association between nodal involvement and both FIGO stage (P = 0.018) and uterine body involvement (P < 0.001), but tumor volume and longitudinal MRI diameter were not statistically significant in unifactor predictors of nodal involvement. In multivariate analysis only uterine body extension, however, was independently related to the risk of nodal involvement. In conclusion, MRI provides noninvasive tumor size evaluation and can also demonstrate invasion of the uterine body that appears to be associated with an increased risk of nodal metastasis. This may provide clinically important prognostic information not available from current FIGO staging.

Diffuse large B-cell non-Hodgkin's lymphoma presenting as Sister Joseph's nodule

Traditionally associated with intra-abdominal epithelial tumours, umbilical metastases (known eponymously as "Sister Joseph's nodules") are often thought to represent advanced malignancy with dismal prognosis. Lymphomas are rare causes of umbilical metastases, with no cases reported prior to 1966 and only three cases since. We describe a patient who presented with diffuse large B-cell non-Hodgkin's lymphoma with "signet ring" morphology manifesting as a "Sister Joseph's nodule", who had an excellent response to systemic therapy, with no detectable disease at 12 months post-completion of therapy. Our experience with this patient highlights the need for accurate histological diagnosis in all umbilical metastases, and dispels the widely held assumption that "Sister Joseph's nodules" represent disseminated malignancy beyond the realm of effective therapy. The patient's unusual histology and pattern of disease involvement are also discussed.

Solitary pulmonary nodules: accuracy and cost-effectiveness of sodium iodide FDG-PET using Australian data

This study uses Australian data to confirm the accuracy of dedicated sodium iodide (NaI) fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in evaluating indeterminate solitary pulmonary nodules (SPNs) and to determine the conditions under which PET could play a cost-effective role in this evaluation. Ninety-two patients from two Australian hospitals in different states underwent FDG-PET for evaluation of an SPN. Observed values for prior probability of malignancy and diagnostic accuracy of PET were applied to previously published decision tree models using published Australian health care costs. The accuracy of FDG-PET was 93% with a sensitivity of 92% and a specificity of 95%. The prior probability of malignancy (0.54), PET sensitivity and PET specificity indicated cost savings per patient of up to EUR 455 (Adollars 774) based on a PET cost of EUR 706 (Adollars 1,200). PET would remain cost-effective for levels of prior probability up to 0.8-0.9 and a PET cost of EUR 736-1,161 (Adollars 1,252-Adollars 1,974). It is concluded that NaI PET is accurate, cost saving and cost-effective for the characterisation of indeterminate pulmonary nodules in Australia. Comparison with previous reports from the United States confirms that FDG-PET can remain cost-effective despite population differences in medical costs, disease prevalence and PET diagnostic performance.

Display of positron emission tomography with Cadplan

Recent clinical experience at Peter MacCallum Cancer Institute (PMCI) with the use of unregistered Positron Emission Tomography (PET) images for radiotherapy target marking in the lung suggests that co-registered PET images would be invaluable. PMCI has three radiotherapy treatment planning systems but none of them currently is able to display or co-register PET images with Computed Tomography (CT) images. This paper details the approach taken to display co-registered PET images with the CADPLAN treatment planning system. CT Image files are normally transferred to Cadplan by DICOM transfer, but the Cadplan DICOM server will not receive (has no presentation context for) PET images. The fundamental design of the CADPLAN system envisages display of only a single image dataset, which must be a CT scan for planning reasons. The problem of data transfer is crudely solved by File Transfer Protocol (FTP) over the network. Fortunately the multislice format of the PET image files makes individual transfer manageable. A menu based C program running at the same time as Cadplan is invoked to sample the DICOM PET Image and create multiple Cadplan CART image format files that are co-registered with each existing transverse CT slice. With the Cadplan in contour mode, the program allows the co-registered PET images to be swapped in and out of the image section of the CART files promptly, while keeping the contour information. This allows radiotherapy target volumes to be marked using transverse PET emission images, and effectively circumvents the design constraints prohibiting the display of more than one image set. Contours can be over-laid for review on reconstructed sagittal or coronal views of CT or PET images constructed using the standard Cadplan tools. Co-registration is facilitated by identical positioning with the aid of lasers and FDG loaded fiducial markers on the PET scanner and CT couch. A polyurethane cast fixed with EFFILOCK is used to ensure identical patient orientation on the CT and PET couches. Since both imaging modalities are without significant geometric distortion the co-registration is then simply a translation. PET transmission images can be used for co-registration verification. The practical implementation of display of PET images with CADPLAN has enabled us to begin a trial of 10 patients, the results of which will be reported separately.

Performance of sodium iodide based (18)F-fluorodeoxyglucose positron emission tomography in the characterization of indeterminate pulmonary nodules or masses

The purpose of this study was to document the accuracy of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) with sodium iodide detectors in characterizing indeterminate lung nodules or masses and in identifying additional extra-lesional findings. 50 consecutive patients without a confident diagnosis of malignancy on CT underwent (18)FDG PET with and without attenuation correction. The diagnosis of malignancy was made using visual diagnostic criteria, and tumour-to-blood pool ratios were calculated. The final diagnosis was established by surgery, biopsy or long-term follow-up. Any additional findings made at PET were recorded and similarly verified. Using blinded visual diagnostic criteria for the differentiation of malignant from benign nodules, sodium iodide PET achieved a sensitivity of 91% (30 of 33 cases), a specificity of 88% (15 of 17 cases), a positive predictive value for malignancy of 94% (30 of 32 cases) and a negative predictive value of 83% (15 of 18 cases). False positives occurred with active tuberculosis and sarcoidosis. False negatives were a 3 cm bronchoalveolar carcinoma, a 1.3 cm sarcoma metastasis and a 1 cm carcinoma. Use of tumour-to-blood pool ratios did not improve performance. PET suggested the presence of nodal or distant metastases in 13 of 33 patients with a malignant pulmonary lesion. These PET findings were confirmed in 11 patients. These results indicate that sodium iodide PET is an accurate tool for the characterization of indeterminate pulmonary masses or nodules and simultaneously provides non-invasive staging information that can alter patient management in up to one-third of such patients. Performance of sodium iodide PET is comparable with reported results for PET scanners using other detector materials.