Baseline PET radiomics outperforms the IPI risk score for prediction of outcome in diffuse large B-cell lymphoma

The objective of this study is to externally validate the clinical positron emission tomography (PET) model developed in the HOVON-84 trial and to compare the model performance of our clinical PET model using the international prognostic index (IPI). In total, 1195 patients with diffuse large B-cell lymphoma (DLBCL) were included in the study. Data of 887 patients from 6 studies were used as external validation data sets. The primary outcomes were 2-year progression-free survival (PFS) and 2-year time to progression (TTP). The metabolic tumor volume (MTV), maximum distance between the largest lesion and another lesion (Dmaxbulk), and peak standardized uptake value (SUVpeak) were extracted. The predictive values of the IPI and clinical PET model (MTV, Dmaxbulk, SUVpeak, performance status, and age) were tested. Model performance was assessed using the area under the curve (AUC), and diagnostic performance, using the positive predictive value (PPV). The IPI yielded an AUC of 0.62. The clinical PET model yielded a significantly higher AUC of 0.71 (P < .001). Patients with high-risk IPI had a 2-year PFS of 61.4% vs 51.9% for those with high-risk clinical PET, with an increase in PPV from 35.5% to 49.1%, respectively. A total of 66.4% of patients with high-risk IPI were free from progression or relapse vs 55.5% of patients with high-risk clinical PET scores, with an increased PPV from 33.7% to 44.6%, respectively. The clinical PET model remained predictive of outcome in 6 independent first-line DLBCL studies, and had higher model performance than the currently used IPI in all studies.

Cost-Effectiveness of Shortening Treatment Duration Based on Interim PET Outcome in Patients With Diffuse Large B-cell Lymphoma

BACKGROUND

Guideline recommendations for diffuse large-B-cell lymphoma (DLBCL) treatment are shifting from long to short treatment duration, although it is still unclear whether shortening treatment duration does not cause any harm. As interim PET (I-PET) has high negative predictive value for progression, we evaluated the cost-effectiveness of shortening treatment duration dependent on I-PET result.

MATERIALS AND METHODS

We developed a Markov cohort model using the PET Re-Analysis (PETRA) database to evaluate a long treatment duration (LTD) strategy, ie 8x R-CHOP or 6x R-CHOP plus 2 R, and a short treatment duration (STD) strategy, ie 6x R-CHOP. Strategies were evaluated separately in I-PET2 positive and I-PET2 negative patients. Outcomes included total costs and quality-adjusted life-years (QALYs) per patient (pp) from a societal perspective. Net monetary benefit (NMB) per strategy was calculated using a willingness-to-pay threshold of €50,000/QALY. Robustness of model predictions was assessed in sensitivity analyses.

RESULTS

In I-PET2 positive patients, shortening treatment duration led to 50.4 additional deaths per 1000 patients. The STD strategy was less effective (-0.161 [95%CI: -0.343;0.028] QALYs pp) and less costly (-€2768 [95%CI: -€8420;€1105] pp). Shortening treatment duration was not cost-effective (incremental NMB -€5281). In I-PET2 negative patients, shortening treatment duration led to 5.0 additional deaths per 1000 patients and a minor difference in effectiveness (-0.007 [95%CI: -0.136;0.140] QALY pp). The STD strategy was less costly (-€5807 [95%CI: -€10,724;-€2685] pp) and led to an incremental NMB of €5449, indicating that it is cost-effective to shorten treatment duration. Robustness of these findings was underpinned by deterministic and probabilistic sensitivity analyses.

CONCLUSION

Treatment duration should not be shortened in I-PET2 positive patients whereas it is cost-effective to shorten treatment duration in I-PET2 negative patients.

Aberrant patterns of PET response during treatment for DLBCL patients with MYC gene rearrangements

Purpose

MYC gene rearrangements in diffuse large B-cell lymphoma (DLBCL) patients are associated with poor prognosis. Our aim was to compare patterns of 2[¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography computed tomography (PET/CT) response in MYC + and MYC- DLBCL patients.

Methods

Interim PET/CT (I-PET) and end of treatment PET/CT (EoT-PET) scans of 81 MYC + and 129 MYC- DLBCL patients from 2 HOVON trials were reviewed using the Deauville 5-point scale (DS). DS1-3 was regarded as negative and DS4-5 as positive. Standardized uptake values (SUV) and metabolic tumor volume (MTV) were quantified at baseline, I-PET, and EoT-PET. Negative (NPV) and positive predictive values (PPV) were calculated using 2-year overall survival.

Results

MYC + DLBCL patients had significantly more positive EoT-PET scans than MYC- patients (32.5 vs 15.7%, p = 0.004). I-PET positivity rates were comparable (28.8 vs 23.8%). In MYC + patients 23.2% of the I-PET negative patients converted to positive at EoT-PET, vs only 2% for the MYC- patients (p = 0.002). Nine (34.6%) MYC + DLBCL showed initially uninvolved localizations at EoT-PET, compared to one (5.3%) MYC- patient. A total of 80.8% of EoT-PET positive MYC + patients showed both increased lesional SUV and MTV compared to I-PET. In MYC- patients, 31.6% showed increased SUV and 42.1% showed increased MTV. NPV of I-PET and EoT-PET was high for both MYC subgroups (81.8–94.1%). PPV was highest at EoT-PET for MYC + patients (61.5%).

Conclusion

MYC + DLBCL patients demonstrate aberrant PET response patterns compared to MYC- patients with more frequent progression during treatment after I-PET negative assessment and new lesions at sites that were not initially involved.

Trial registration number and date of registration

HOVON-84: EudraCT: 2006–005,174-42, retrospectively registered 01–08-2008. HOVON-130: EudraCT: 2014–002,654-39, registered 26–01-2015

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05498-7.

Pelvic lymph-node staging with 18F-DCFPyL PET/CT prior to extended pelvic lymph-node dissection in primary prostate cancer - the SALT trial

PURPOSE

The detection of lymph-node metastases (N1) with conventional imaging such as magnetic resonance imaging (MRI) and computed tomography (CT) is inadequate for primarily diagnosed prostate cancer (PCa). Prostate-specific membrane antigen (PSMA) PET/CT is successfully introduced for the staging of (biochemically) recurrent PCa. Besides the frequently used 68gallium-labelled PSMA tracers, 18fluorine-labelled PSMA tracers are available. This study examined the diagnostic accuracy of 18F-DCFPyL (PSMA) PET/CT for lymph-node staging in primary PCa.

METHODS

This was a prospective, multicentre cohort study. Patients with primary PCa underwent 18F-DCFPyL PET/CT prior to robot-assisted radical prostatectomy (RARP) with extended pelvic lymph-node dissection (ePLND). Patients were included between October 2017 and January 2020. A Memorial Sloan Kettering Cancer Centre (MSKCC) nomogram risk probability of ≥ 8% of lymph-node metastases was set to perform ePLND. All images were reviewed by two experienced nuclear physicians, and were compared with post-operative histopathologic results.

RESULTS

A total of 117 patients was analysed. Lymph-node metastases (N1) were histologically diagnosed in 17/117 patients (14.5%). The sensitivity, specificity, positive predictive value and negative predictive value for the 18F-DCFPyL PET/CT detection of pelvic lymph-node metastases on a patient level were 41.2% (confidence interval (CI): 19.4-66.5%), 94.0% (CI 86.9-97.5%), 53.8% (CI 26.1-79.6%) and 90.4% (CI 82.6-95.0%), respectively.

CONCLUSION

18F-DCFPyL PET/CT showed a high specificity (94.4%), yet a limited sensitivity (41.2%) for the detection of pelvic lymph-node metastases in primary PCa. This implies that current PSMA PET/CT imaging cannot replace diagnostic ePLND. Further research is necessary to define the exact place of PSMA PET/CT imaging in the primary staging of PCa.

Detection of prostate cancer with 18F-DCFPyL PET/CT compared to final histopathology of radical prostatectomy specimens: is PSMA-targeted biopsy feasible? The DeTeCT trial

PURPOSE

In primary prostate cancer (PCa) patients, accurate staging and histologic grading are crucial to guide treatment decisions. ¹⁸F-DCFPyL (PSMA)-PET/CT has been successfully introduced for (re)staging PCa, showing high accuracy to localise PCa in lymph nodes and/or osseous structures. The diagnostic performance of ¹⁸F-DCFPyL-PET/CT in localizing primary PCa within the prostate gland was assessed, allowing for PSMA-guided targeted-prostate biopsy.

METHODS

Thirty patients with intermediate-/high-risk primary PCa were prospectively enrolled between May 2018 and May 2019 and underwent ¹⁸F-DCFPyL-PET/CT prior to robot-assisted radical prostatectomy (RARP). Two experienced and blinded nuclear medicine physicians assessed tumour localisation within the prostate gland on PET/CT, using a 12-segment mapping model of the prostate. The same model was used by a uro-pathologist for the RARP specimens. Based on PET/CT imaging, a potential biopsy recommendation was given per patient, based on the size and PET-intensity of the suspected PCa localisations. The biopsy recommendation was correlated to final histopathology in the RARP specimen. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for clinically significant PCa (csPCa, Gleason score ≥ 3 + 4 = 7) were assessed.

RESULTS

The segments recommended for potential targeted biopsy harboured csPCA in 28/30 patients (93%), and covered the highest Gleason score PCa segment in 26/30 patient (87%). Overall, 122 of 420 segments (29.0%) contained csPCa at final histopathological examination. Sensitivity, specificity, PPV and NPV for csPCa per segment using ¹⁸F-DCFPyL-PET/CT were 61.4%, 88.3%, 68.1% and 84.8%, respectively.

CONCLUSIONS

When comparing the PCa-localisation on ¹⁸F-DCFPyL-PET/CT with the RARP specimens, an accurate per-patient detection (93%) and localisation of csPCa was found. Thus, ¹⁸F-DCFPyL-PET/CT potentially allows for accurate PSMA-targeted biopsy.

Correction to: [89Zr]Zr-cetuximab PET/CT as biomarker for cetuximab monotherapy in patients with RAS wild-type advanced colorectal cancer

Missing Electronic Supplementary Materials.

[89Zr]Zr-cetuximab PET/CT as biomarker for cetuximab monotherapy in patients with RAS wild-type advanced colorectal cancer

PURPOSE

One-third of patients with RAS wild-type mCRC do not benefit from anti-EGFR monoclonal antibodies. This might be a result of variable pharmacokinetics and insufficient tumor targeting. We evaluated cetuximab tumor accumulation on [⁸⁹Zr]Zr-cetuximab PET/CT as a potential predictive biomarker and determinant for an escalating dosing strategy.

PATIENTS AND METHODS

PET/CT imaging of [⁸⁹Zr]Zr-cetuximab (37 MBq/10 mg) after a therapeutic pre-dose (500 mg/m² ≤ 2 h) cetuximab was performed at the start of treatment. Patients without visual tumor uptake underwent dose escalation and a subsequent [⁸⁹Zr]Zr-cetuximab PET/CT. Treatment benefit was defined as stable disease or response on CT scan evaluation after 8 weeks.

RESULTS

Visual tumor uptake on [⁸⁹Zr]Zr-cetuximab PET/CT was observed in 66% of 35 patients. There was no relationship between PET positivity and treatment benefit (52% versus 80% for PET-negative, P = 0.16), progression-free survival (3.6 versus 5.7 months, P = 0.15), or overall survival (7.1 versus 9.4 months, P = 0.29). However, in 67% of PET-negative patients, cetuximab dose escalation (750-1250 mg/m²) was applied, potentially influencing outcome in this group. None of the second [⁸⁹Zr]Zr-cetuximab PET/CT was positive. Eighty percent of patients without visual tumor uptake had treatment benefit, making [⁸⁹Zr]Zr-cetuximab PET/CT unsuitable as a predictive biomarker. Tumor SUV_peak did not correlate to changes in tumor size on CT (P = 0.23), treatment benefit, nor progression-free survival. Cetuximab pharmacokinetics were not related to treatment benefit. BRAF mutations, right-sidedness, and low sEGFR were correlated with intrinsic resistance to cetuximab.

CONCLUSION

Tumor uptake on [⁸⁹Zr]Zr-cetuximab PET/CT failed to predict treatment benefit in patients with RAS wild-type mCRC receiving cetuximab monotherapy. BRAF mutations, right-sidedness, and low sEGFR correlated with intrinsic resistance to cetuximab.

Early lesion detection with 18F-DCFPyL PET/CT in 248 patients with biochemically recurrent prostate cancer

Purpose

Prostate-specific membrane antigen (PSMA) PET/CT is increasingly used in patients with biochemically recurrent prostate cancer (BCR), mostly using gallium-68 (¹⁶⁸Ga)-labelled radiotracers. Alternatively, fluorine-18 (¹⁸F)-labelled PSMA tracers are available, such as ¹⁸F-DCFPyL, which offer enhanced image quality and therefore potentially increased detection of small metastases. In this study we evaluate the lesion detection efficacy of ¹⁸F-DCFPyL PET/CT in patients with BCR and determine the detection efficacy as a function of their PSA value.

Methods

A total of 248 consecutive patients were evaluated and underwent scanning with ¹⁸F-DCFPyL PET/CT for BCR between November 2016 and 2018 in two hospitals in the Netherlands. Patients were examined after radical prostatectomy (52%), external-beam radiation therapy (42%) or brachytherapy (6%). Imaging was performed 120 min after injection of a median dose of 311 MBq ¹⁸F-DCFPyL.

Results

In 214 out of 248 PET/CT scans (86.3%), at least one lesion suggestive of cancer recurrence was detected (‘positive scan’). Scan positivity increased with higher PSA values: 17/29 scans (59%) with PSA values <0.5 ng/ml; 20/29 (69%) with PSA 0.5 to <1.0 ng/ml; 35/41 (85%) with PSA 1.0 to <2.0 ng/ml; 69/73 (95%) with PSA 2.0 to <5.0 ng/ml; and 73/76 (96%) with PSA ≥5.0 ng/ml. Interestingly, suspicious lesions outside the prostatic fossa were detected in 39–50% of patients with PSA <1.0 ng/ml after radical prostatectomy (i.e. candidates for salvage radiotherapy).

Conclusion

¹⁸F-DCFPyL PET/CT offers early detection of lesions in patients with BCR, even at PSA levels <0.5 ng/ml. These results appear to be comparable to those reported for ⁶⁸Ga-PSMA and ¹⁸F-PSMA-1007, with potentially increased detection efficacy compared to ⁶⁸Ga-PSMA for patients with PSA <2.0.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04385-6) contains supplementary material, which is available to authorized users.

Perioperative PET/CT lymphoscintigraphy and fluorescent real-time imaging for sentinel lymph node mapping in early staged colon cancer

Purpose

Using current optical imaging techniques and gamma imaging modalities, perioperative sentinel lymph node (SLN) identification in colon cancer can be difficult when the SLN is located near the primary tumour or beneath a thick layer of (fat) tissue. Sentinel lymph node mapping using PET/CT lymphoscintigraphy combined with real-time visualization of the SLN using near-infrared imaging has shown promising results in several types of cancer and may facilitate the successful identification of the number and location of the SLN in early colon cancer.

Methods

Clinical feasibility of PET/CT lymphoscintigraphy using preoperative endoscopically injected [⁸⁹Zr]Zr-Nanocoll and intraoperative injection of the near-infrared (NIR) tracer Indocyanine Green (ICG) was evaluated in ten early colon cancer patients. Three preoperative PET/CT scans and an additional ex vivo scan of the specimen were performed after submucosal injection of [⁸⁹Zr]Zr-Nanocoll. All SLNs and other lymph nodes underwent extensive pathological examination for metastases. A histopathological proven lymph node visible at preoperative PET/CT and identified at PET/CT of the specimen was defined as SLN.

Results

A total of 27 SLNs were harvested in seven out of eight patients with successful injection of both tracers. In one patient no SLNs were assigned preoperatively. In two patients injection of [⁸⁹Zr]Zr-Nanocoll failed due to incorrect needle positioning. Twenty-one (78%) SLNs were found intraoperatively using NIR-imaging. Eleven of the 27 (41%) SLNs were located near the primary tumour (< 2 cm). Those six SLNs not found intraoperatively with NIR-imaging were all located close to the tumour. In all seven patients at least one SLN could be assigned at preoperative imaging 24 h after tracer administration. One SLN contained metastases detected by immunohistochemistry. No metastases were found in the non-SLNs.

Conclusions

This study shows the potential of preoperative PET/CT lymphoscintigraphy to inform the surgeon about the number and location of SLNs in patients with early colon cancer. The additional use of NIR-imaging allows for intraoperative identification of these SLNs which are invisible with conventional white light imaging. Further research is necessary to improve and simplify the technique. We recommend perioperative SLN identification using a preoperative lymphoscintigraphy scan just before surgery approximately 24 h after injection. Additionally a postoperative scan of the specimen combined with intraoperative real-time NIR-imaging should be performed.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04284-w) contains supplementary material, which is available to authorized users.

Partial-volume correction in dynamic PET-CT: effect on tumor kinetic parameter estimation and validation of simplified metrics

Background

Partial-volume effects generally result in an underestimation of tumor tracer uptake on PET-CT for small lesions, necessitating partial-volume correction (PVC) for accurate quantification. However, investigation of PVC in dynamic oncological PET studies to date is scarce. The aim of this study was to investigate PVC’s impact on tumor kinetic parameter estimation from dynamic PET-CT acquisitions and subsequent validation of simplified semi-quantitative metrics. Ten patients with EGFR-mutated non-small cell lung cancer underwent dynamic ¹⁸F-fluorothymidine PET-CT before, 7 days after, and 28 days after commencing treatment with a tyrosine kinase inhibitor. Parametric PVC was applied using iterative deconvolution without and with highly constrained backprojection (HYPR) denoising, respectively. Using an image-derived input function with venous parent plasma calibration, we estimated full kinetic parameters V_T, K₁, and k₃/k₄ (BP_ND) using a reversible two-tissue compartment model, and simplified metrics (SUV and tumor-to-blood ratio) at 50–60 min post-injection.

Results

PVC had a non-linear effect on measured activity concentrations per timeframe. PVC significantly changed each kinetic parameter, with a median increase in V_T of 11.8% (up to 25.1%) and 10.8% (up to 21.7%) without and with HYPR, respectively. Relative changes in kinetic parameter estimates vs. simplified metrics after applying PVC were poorly correlated (correlations 0.36–0.62; p < 0.01). PVC increased correlations between simplified metrics and V_T from 0.82 and 0.81 (p < 0.01) to 0.90 and 0.88 (p < 0.01) for SUV and TBR, respectively, albeit non-significantly. PVC also increased correlations between treatment-induced changes in simplified metrics vs. V_T at 7 (SUV) and 28 (SUV and TBR) days after treatment start non-significantly. Delineation on partial-volume corrected PET images resulted in a median decrease in metabolic tumor volume of 14.3% (IQR − 22.1 to − 7.5%), and increased the effect of PVC on kinetic parameter estimates.

Conclusion

PVC has a significant impact on tumor kinetic parameter estimation from dynamic PET-CT data, which differs from its effect on simplified metrics. However, it affected validation of these simplified metrics both as single measurements and as biomarkers of treatment response only to a small extent. Future dynamic PET studies should preferably incorporate PVC.

Trial registration

Dutch Trial Register, NTR3557.

Electronic supplementary material

The online version of this article (10.1186/s13550-019-0483-z) contains supplementary material, which is available to authorized users.

Use of Diffusion-Weighted Imaging and 18F-Fluorodeoxyglucose Positron Emission Tomography Combined With Computed Tomography in the Response Assessment for (Chemo)radiotherapy in Head and Neck Squamous Cell Carcinoma

AIMS

Our purpose was to assess the diagnostic accuracy and prognostic value of diffusion-weighted imaging (DWI) and ¹⁸F-fluorodeoxyglucose positron emission tomography combined with computed tomography (¹⁸F-FDG-PET/CT) carried out 3-6 months after (chemo)radiotherapy in head and neck squamous cell carcinoma.

MATERIALS AND METHODS

For this retrospective cohort study we included 82 patients with advanced-stage head and neck squamous cell carcinoma treated between 2012 and 2015. Primary tumours and lymph nodes were assessed separately. DWI was analysed qualitatively and quantitatively. ¹⁸F-FDG-PET/CT was evaluated using the Hopkins criteria. Dichotomous qualitative analysis was carried out for both modalities. Cox regression analysis was used for univariate analysis of recurrence-free survival (RFS). Significant univariate parameters were included in multivariate analysis.

RESULTS

In 12 patients, locoregional recurrence occurred. With all imaging strategies, either single-modality or multi-modality, a high negative predictive value (NPV) was achieved (94.3-100%). In response evaluation of the primary site, the preferred strategy is ¹⁸F-FDG-PET/CT only, which resulted in a sensitivity of 85.7%, specificity of 86.5%, positive predictive value (PPV) of 37.5% and NPV of 98.5%. For response evaluation of the neck, the best results were obtained with a sequential approach only including the second modality in positive reads of the first modality. It did not matter which modality was assessed first. This strategy for lymph node assessment resulted in a sensitivity, specificity, PPV and NPV of 83.3%, 95.6%, 62.5%, and 98.5%, respectively. After correction for received treatment and human papillomavirus status, primary tumour (P = 0.009) or lymph node (P < 0.001) Hopkins score ≥4 on ¹⁸F-FDG-PET/CT remained significant predictors of RFS.

CONCLUSION

For response evaluation of the primary tumour ¹⁸F-FDG-PET/CT only is the preferred strategy, whereas for the neck a sequential approach including both DWI and ¹⁸F-FDG-PET/CT resulted in the best diagnostic accuracy for follow-up after (chemo)radiotherapy. Qualitative analysis of ¹⁸F-FDG-PET/CT is a stronger predictor of RFS than DWI analysis.

Radiomics analysis of pre-treatment [18F]FDG PET/CT for patients with metastatic colorectal cancer undergoing palliative systemic treatment

BACKGROUND

The aim of this study was to assess radiomics features on pre-treatment [¹⁸F]FDG positron emission tomography (PET) as potential biomarkers for response and survival in patients with metastatic colorectal cancer (mCRC).

METHODS

Patients with mCRC underwent [¹⁸F]FDG PET/computed tomography (CT) prior to first- or third-line palliative systemic treatment. Tumour lesions were semiautomatically delineated and standard uptake value (SUV), metabolically active tumour volume (MATV), total lesion glycolysis (TLG), entropy, area under the curve of the cumulative SUV-volume histogram (AUC-CSH), compactness and sphericity were obtained.

RESULTS

Lesions of 47 patients receiving third-line systemic treatment had higher SUV_max, SUV_peak, SUV_mean, MATV and TLG, and lower AUC-CSH, compactness and sphericity compared to 52 patients receiving first-line systemic treatment. Therefore, first- and third-line groups were evaluated separately. In the first-line group, anatomical changes on CT correlated negatively with TLG (ρ = 0.31) and MATV (ρ = 0.36), and positively with compactness (ρ = -0.27) and sphericity (ρ = -0.27). Patients without benefit had higher mean entropy (p = 0.021). Progression-free survival (PFS) and overall survival (OS) were worse with a decreased mean AUC [hazard ratio (HR) 0.86, HR 0.77] and increase in mean MATV (HR 1.15, HR 1.22), sum MATV (HR 1.14, HR 1.19), mean TLG (HR 1.16, HR 1.22) and sum TLG (HT1.12, HR1.18). In the third-line group, AUC-CSH correlated negatively with anatomical change (ρ = 0.21). PFS and OS were worse with an increased mean MATV (HR 1.27, HR 1.68), sum MATV (HR 1.35, HR 2.04), mean TLG (HR 1.29, HR 1.52) and sum TLG (HT 1.27, HR 1.80). SUV_max and SUV_peak negatively correlated with OS (HR 1.19, HR 1.21). Cluster analysis of the 10 radiomics features demonstrated no complementary value in identifying aggressively growing lesions or patients with impaired survival.

CONCLUSION

We demonstrated an association between improved clinical outcome and pre-treatment low tumour volume and heterogeneity as well as high sphericity on [¹⁸F]FDG PET. Future PET imaging research should include radiomics features that incorporate tumour volume and heterogeneity when correlating PET data with clinical outcome.

Repeatability of quantitative 18F-FLT uptake measurements in solid tumors: an individual patient data multi-center meta-analysis

INTRODUCTION

3'-deoxy-3'-[18F]fluorothymidine (18F-FLT) positron emission tomography (PET) provides a non-invasive method to assess cellular proliferation and response to antitumor therapy. Quantitative 18F-FLT uptake metrics are being used for evaluation of proliferative response in investigational setting, however multi-center repeatability needs to be established. The aim of this study was to determine the repeatability of 18F-FLT tumor uptake metrics by re-analyzing individual patient data from previously published reports using the same tumor segmentation method and repeatability metrics across cohorts.

METHODS

A systematic search in PubMed, EMBASE.com and the Cochrane Library from inception-October 2016 yielded five 18F-FLT repeatability cohorts in solid tumors. 18F-FLT avid lesions were delineated using a 50% isocontour adapted for local background on test and retest scans. SUVmax, SUVmean, SUVpeak, proliferative volume and total lesion uptake (TLU) were calculated. Repeatability was assessed using the repeatability coefficient (RC = 1.96 × SD of test-retest differences), linear regression analysis, and the intra-class correlation coefficient (ICC). The impact of different lesion selection criteria was also evaluated.

RESULTS

Images from four cohorts containing 30 patients with 52 lesions were obtained and analyzed (ten in breast cancer, nine in head and neck squamous cell carcinoma, and 33 in non-small cell lung cancer patients). A good correlation was found between test-retest data for all 18F-FLT uptake metrics (R2 ≥ 0.93; ICC ≥ 0.96). Best repeatability was found for SUVpeak (RC: 23.1%), without significant differences in RC between different SUV metrics. Repeatability of proliferative volume (RC: 36.0%) and TLU (RC: 36.4%) was worse than SUV. Lesion selection methods based on SUVmax ≥ 4.0 improved the repeatability of volumetric metrics (RC: 26-28%), but did not affect the repeatability of SUV metrics.

CONCLUSIONS

In multi-center studies, differences ≥ 25% in 18F-FLT SUV metrics likely represent a true change in tumor uptake. Larger differences are required for FLT metrics comprising volume estimates when no lesion selection criteria are applied.

Validation of [18F]FLT as a perfusion-independent imaging biomarker of tumour response in EGFR-mutated NSCLC patients undergoing treatment with an EGFR tyrosine kinase inhibitor

Background

3′-Deoxy-3′-[¹⁸F]fluorothymidine ([¹⁸F]FLT) was proposed as an imaging biomarker for the assessment of in vivo cellular proliferation with positron emission tomography (PET). The current study aimed to validate [¹⁸F]FLT as a perfusion-independent PET tracer, by gaining insight in the intra-tumoural relationship between [¹⁸F]FLT uptake and perfusion in non-small cell lung cancer (NSCLC) patients undergoing treatment with a tyrosine kinase inhibitor (TKI).

Six patients with metastatic NSCLC, having an activating epidermal growth factor receptor (EGFR) mutation, were included in this study. Patients underwent [¹⁵O]H₂O and [¹⁸F]FLT PET/CT scans at three time points: before treatment and 7 and 28 days after treatment with a TKI (erlotinib or gefitinib). Parametric analyses were performed to generate quantitative 3D images of both perfusion measured with [¹⁵O]H₂O and proliferation measured with [¹⁸F]FLT volume of distribution (V_T). A multiparametric classification was performed by classifying voxels as low and high perfusion and/or low and high [¹⁸F]FLT V_T using a single global threshold for all scans and subjects. By combining these initial classifications, voxels were allocated to four categories (low perfusion-low V_T, low perfusion-high V_T, high perfusion-low V_T and high perfusion-high V_T).

Results

A total of 17 perfusion and 18 [¹⁸F]FLT PET/CT scans were evaluated. The average tumour values across all lesions were 0.53 ± 0.26 mL cm^− 3 min^− 1 and 4.25 ± 1.71 mL cm^− 3 for perfusion and [¹⁸F]FLT V_T, respectively. Multiparametric analysis suggested a shift in voxel distribution, particularly regarding the V_T: from an average of ≥ 77% voxels classified in the “high V_T category” to ≥ 85% voxels classified in the “low V_T category”. The shift was most prominent 7 days after treatment and remained relatively similar afterwards. Changes in perfusion and its spatial distribution were minimal.

Conclusion

The present study suggests that [¹⁸F]FLT might be a perfusion-independent PET tracer for measuring tumour response as parametric changes in [¹⁸F]FLT uptake occurred independent from changes in perfusion.

Trial registration

Nederlands Trial Register (NTR), NTR3557. Registered 2 August 2012

Electronic supplementary material

The online version of this article (10.1186/s13550-018-0376-6) contains supplementary material, which is available to authorized users.

Diagnostic Accuracy of Neuroimaging to Delineate Diffuse Gliomas within the Brain: A Meta-Analysis

BACKGROUND

Brain imaging in diffuse glioma is used for diagnosis, treatment planning, and follow-up.

PURPOSE

In this meta-analysis, we address the diagnostic accuracy of imaging to delineate diffuse glioma.

DATA SOURCES

We systematically searched studies of adults with diffuse gliomas and correlation of imaging with histopathology.

STUDY SELECTION

Study inclusion was based on quality criteria. Individual patient data were used, if available.

DATA ANALYSIS

A hierarchic summary receiver operating characteristic method was applied. Low- and high-grade gliomas were analyzed in subgroups.

DATA SYNTHESIS

Sixty-one studies described 3532 samples in 1309 patients. The mean Standard for Reporting of Diagnostic Accuracy score (13/25) indicated suboptimal reporting quality. For diffuse gliomas as a whole, the diagnostic accuracy was best with T2-weighted imaging, measured as area under the curve, false-positive rate, true-positive rate, and diagnostic odds ratio of 95.6%, 3.3%, 82%, and 152. For low-grade gliomas, the diagnostic accuracy of T2-weighted imaging as a reference was 89.0%, 0.4%, 44.7%, and 205; and for high-grade gliomas, with T1-weighted gadolinium-enhanced MR imaging as a reference, it was 80.7%, 16.8%, 73.3%, and 14.8. In high-grade gliomas, MR spectroscopy (85.7%, 35.0%, 85.7%, and 12.4) and ¹¹C methionine-PET (85.1%, 38.7%, 93.7%, and 26.6) performed better than the reference imaging.

LIMITATIONS

True-negative samples were underrepresented in these data, so false-positive rates are probably less reliable than true-positive rates. Multimodality imaging data were unavailable.

CONCLUSIONS

The diagnostic accuracy of commonly used imaging is better for delineation of low-grade gliomas than high-grade gliomas on the basis of limited evidence. Improvement is indicated from advanced techniques, such as MR spectroscopy and PET.

Prediction of disease-free survival using relative change in FDG-uptake early during neoadjuvant chemoradiotherapy for potentially curable esophageal cancer: A prospective cohort study

18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) has been investigated as a tool for monitoring response to neoadjuvant chemo- and chemoradiotherapy (CT and CRT, respectively) and as a predictor for survival in patients with esophageal cancer. In contrast to patients who undergo neoadjuvant CT, it is not known whether patients who are clinically identified as responders after neoadjuvant CRT show better disease-free survival (DFS) than patients identified as nonresponders. The aim of the study was to determine the predictive value of FDG-uptake measured prior to and early during neoadjuvant CRT. Patients treated with neoadjuvant CRT between 2004 and 2009 within a randomized trial were included. FDG-uptake was measured at baseline and after 14 days of CRT. According to the PERCIST-criteria, patients were allocated to have metabolic response, stable disease, or progression. Patients were followed until recurrence of disease or death. The predictive value of FDG-PET was determined with univariable and multivariable analysis in patients who underwent potentially curative surgery. One-hundred and six patients were included in the analysis. Minimal follow-up for surviving patients was 60 months. No significant differences in DFS were found between patients with metabolic response, stable disease, or progression, with 5-year DFS rates of 66%, 53%, and 67%, respectively (P = 0.39). Relative change in FDG uptake after 14 days of CRT is not associated with DFS in patients with esophageal cancer undergoing neoadjuvant chemoradiotherapy followed by surgery. These measurements should not be used for prognostication in this specific group of patients.

Molecular imaging as a tool to investigate heterogeneity of advanced HER2-positive breast cancer and to predict patient outcome under trastuzumab emtansine (T-DM1): the ZEPHIR trial

BACKGROUND

Only human epidermal growth factor receptor (HER)2 status determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) has been validated to predict efficacy of HER2-targeting antibody-drug-conjugate trastuzumab emtansine (T-DM1). We propose molecular imaging to explore intra-/interpatient heterogeneity in HER2 mapping of metastatic disease and to identify patients unlikely to benefit from T-DM1.

PATIENTS AND METHODS

HER2-positive mBC patients with IHC3+ or FISH ≥ 2.2 scheduled for T-DM1 underwent a pretreatment HER2-positron emission tomography (PET)/computed tomography (CT) with (89)Zr-trastuzumab. [(18)F]2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT was performed at baseline and before T-DM1 cycle 2. Patients were grouped into four HER2-PET/CT patterns according to the proportion of FDG-avid tumor load showing relevant (89)Zr-trastuzumab uptake (>blood pool activity): patterns A and B were considered positive (>50% or all of the tumor load 'positive'); patterns C and D were considered negative (>50% or all of the tumor load 'negative'). Early FDG-PET/CT was defined as nonresponding when >50% of the tumor load showed no significant reduction of FDG uptake (<15%). Negative (NPV) and positive predictive values (PPV) of HER2-PET/CT, early FDG response and their combination were assessed to predict morphological response (RECIST 1.1) after three T-DM1 cycles and time-to-treatment failure (TTF).

RESULTS

In the 56 patients analyzed, 29% had negative HER2-PET/CT while intrapatient heterogeneity (patterns B and C) was found in 46% of patients. Compared with RECIST1.1, respective NPV/PPV for HER2-PET/CT were 88%/72% and 83%/96% for early FDG-PET/CT. Combining HER2-PET/CT and FDG-PET/CT accurately predicted morphological response (PPV and NPV: 100%) and discriminated patients with a median TTF of only 2.8 months [n = 12, 95% confidence interval (CI) 1.4-7.6] from those with a TTF of 15 months (n = 25, 95% CI 9.7-not calculable).

CONCLUSIONS

Pretreatment imaging of HER2 targeting, combined with early metabolic response assessment holds great promise for improving the understanding of tumor heterogeneity in mBC and for selecting patients who will/will not benefit from T-DM1.

CLINICALTRIALSGOV IDENTIFIER

NCT01565200.

Epidermal growth factor receptor (EGFR) and prostaglandin-endoperoxide synthase 2 (PTGS2) are prognostic biomarkers for patients with resected colorectal cancer liver metastases

Background:

Resection of colorectal cancer liver metastasis (CRCLM) with curative intent has long-term benefit in ∼40% of cases. Prognostic biomarkers are needed to improve clinical management and reduce futile surgeries. Expression of epidermal growth factor receptor (EGFR) and prostaglandin-endoperoxide synthase 2 (PTGS2; also known as cyclooxygenase-2) has been associated with carcinogenesis and survival. We investigated the prognostic value of EGFR and PTGS2 expression in patients with resected CRCLM.

Methods:

Formalin-fixed paraffin-embedded CRCLM tissue and corresponding primary tumour specimens from a multi-institutional cohort of patients who underwent liver resection between 1990 and 2010 were incorporated into tissue microarrays (TMAs). TMAs were stained for EGFR and PTGS2 by immunohistochemistry. The hazard rate ratio (HRR) for the association between expression in CRCLM and overall survival was calculated using a 500-fold cross-validation procedure.

Results:

EGFR and PTGS2 expression could be evaluated in 323 and 351 patients, respectively. EGFR expression in CRCLM was associated with poor prognosis (HRR 1.54; P<0.01) with a cross-validated HRR of 1.47 (P=0.03). PTGS2 expression was also associated with poor prognosis (HRR 1.60; P<0.01) with a cross-validated HRR of 1.63 (P<0.01). Expression of EGFR and PTGS2 remained prognostic after multivariate analysis with standard clinicopathological variables (cross-validated HRR 1.51; P=0.02 and cross-validated HRR 1.59; P=0.01, respectively). Stratification for the commonly applied systemic therapy regimens demonstrated prognostic value for EGFR and PTGS2 only in the subgroup of patients who were not treated with systemic therapy (HRR 1.78; P<0.01 and HRR 1.64; P=0.04, respectively), with worst prognosis when both EGFR and PTGS2 were highly expressed (HRR 3.08; P<0.01). Expression of PTGS2 in CRCLM was correlated to expression in patient-matched primary tumours (P=0.02, 69.2% concordance).

Conclusions:

EGFR and PTGS2 expressions are prognostic molecular biomarkers with added value to standard clinicopathological variables for patients with resectable CRCLM.

CT-perfusion versus [(15)O]H2O PET in lung tumors: effects of CT-perfusion methodology

PURPOSE

Nowadays, PET and dynamic contrast enhanced CT or MRI are used to assess tumor blood perfusion. Although [(15)O]H2O PET is the gold standard, it is hardly available for routine clinical practice, due to the short half-life of (15)O. However, the lack of uniformity in scanning and analytic methods limits the use of CT perfusion (CTP) in clinical trials and practice. This study compares [(15)O]H2O PET with CT based perfusion in lung tumors and assesses the effects of various CTP postprocessing and analytical methods on the CTP results using [(15)O]H2O PET as the reference technique.

METHODS

Various CTP analysis and image postprocessing methods were assessed. Furthermore, parametric images were obtained using the Slope method. Volumes of interests were defined using several different segmentation methods including Hounsfield unit based contouring thresholds, both with and without framewise application of dynamic contouring thresholds to exclude lung tissue or intravascular contrast. A head-to-head comparison of tumor perfusion obtained by CTP and [(15)O]H2O PET was performed using linear regressions, Bland-Altman plots, and an intraclass correlation coefficient (ICC). In addition, the different postprocessing methods were compared reciprocally.

RESULTS

In six lung cancer patients, perfusion assessed using CTP studies combined with the Slope method correlated best with [(15)O]H2O PET (ICC = 0.88; R(2) = 0.89; Y = 0.80). The Mullani-Gould method showed best correlation with the Slope method (ICC ≥ 0.71; R(2) ≥ 0.80; Y = 0.71-1.35). These correlations were obtained using dynamic contouring thresholds and show the influence of CTP postprocessing methods.

CONCLUSIONS

Tumor perfusion assessed by CTP in combination with dynamic contouring thresholds using the Slope method correlates well with [(15)O]H2O PET. This suggests that CTP can be used as a method to evaluate tumor perfusion in lung cancer.

Aurora kinase A (AURKA) expression in colorectal cancer liver metastasis is associated with poor prognosis

Background:

Five-year survival after resection of colorectal cancer liver metastasis (CRLCM) is <30%. We recently found that aurora kinase A (AURKA) drives 20q gain-associated tumour progression and is associated with disease recurrence. This study evaluates the prognostic value of AURKA expression in CRCLM of patients who underwent liver resection.

Methods:

Tissue microarrays (TMAs) were generated using formalin-fixed paraffin-embedded CRCLM and matched primary tumour from a multi-institutional cohort of patients with CRCLM who underwent liver resection between 1990 and 2010. Tissue microarrays were stained for AURKA using immunohistochemistry, and a hazard rate ratio (HRR) for the association between overall survival (OS) and nuclear AURKA expression in CRCLM was calculated. Results were validated by 500-fold cross-validation.

Results:

The expression of AURKA was evaluated in CRCLM of 343 patients. High AURKA expression was associated with poor OS (HRR 1.55, P<0.01), with a cross-validated average HRR of 1.57 (P=0.02). Average HRR was adjusted for the established prognostic clinicopathological variables in a multivariate analysis (average HRR 1.66; P=0.02). The expression of AURKA in CRCLM was correlated to its expression in corresponding primary tumour (P<0.01).

Conclusion:

The expression of AURKA protein is a molecular biomarker with prognostic value for patients with CRCLM, independent of established clinicopathological variables.

Outcome of clinical stage III melanoma patients with FDG-PET and whole-body CT added to the diagnostic workup

BACKGROUND

Combined whole-body FDG-PET and CT provide the most comprehensive staging of melanoma patients with palpable lymph node metastases (LNM). The aim of this study is to analyze survival of FDG-PET and CT negative or positive melanoma patients and to assess which factors have independent prognostic impact on survival of these patients.

METHODS

Patients with palpable and histologically or cytologically proven LNM of melanoma, referred to participating hospitals for examination with FDG-PET and CT, were selected from a previous study. Melanoma-specific survival (MSS) and disease-free period (DFP) were analyzed for FDG-PET and CT positive and negative patients using the Kaplan-Meier method. Cox-regression analysis was performed to analyze which patient or melanoma characteristics had significant impact on MSS or DFP.

RESULTS

For all 252 patients 5-year MSS was 38.2%. For FDG-PET and CT negative and positive patients 5-year MSS was 47.6 and 16.9%, respectively. Disease-free period for FDG-PET and CT negative patients was 46.0% after 5 years. Gender, a positive FDG-PET and CT, LNM in axilla compared to head or neck, and presence of extranodal growth were independent factors for worse MSS in all patients. Positive FDG-PET and CT was the most important prognostic factor for MSS with a hazard ratio of 2.54 (95% CI, 1.55-4.17, P<0.001).

CONCLUSIONS

Staging melanoma patients with palpable LNM is more accurate when whole-body FDG-PET and CT is added to the diagnostic workup. Hence, FDG-PET and CT, preferably combined, are indicated in the staging of clinical stage III melanoma patients.

Prognostic value of the standardized uptake value for (18)F-fluorodeoxyglucose in patients with stage IIIB melanoma

Purpose

FDG PET/CT is an excellent tool to detect melanoma metastases and also allows quantification of FDG uptake using standardized uptake value (SUV). The aim of this study was to prospectively investigate the potential prognostic value of SUV for disease-free survival (DFS) and disease-specific survival (DSS) for patients with stage IIIB melanoma.

Methods

From November 2003 to March 2008, all consecutive patients were included in the present study. Inclusion criteria were: palpable, histology- or cytology-proven lymph node metastases of melanoma, and referred to the University Medical Centre Groningen for FDG PET and CT examination. Patients without distant metastases were evaluated. Multivariable survival analysis was performed to determine whether SUV was associated with DFS and DSS (Cox proportional hazard analysis).

Results

In 80 patients (without distant metastases, 65 %) SUV could be measured. Overall 5-year DFS was 41 % (95% CI 26–56 %) and 24 % (95% CI 12–38 %) in patients with a low and high SUVmean (p = 0.02), respectively. Overall 5-year DSS was 48 % (95% CI 31–62 %) and 30 % (95% CI 17–45 %) in patients with a low and high SUVmean (p = 0.04), respectively. In the multivariable analysis, SUVmean was associated with DFS (hazard ratio 1.7; p = 0.048), but was not associated with DSS (hazard ratio 1.6; p = 0.1). The number of positive nodes, extranodal growth and gender were also associated with survival.

Conclusion

FDG uptake in clinically overt nodal melanoma metastases is inversely associated with DFS. Univariate analysis showed an association with DSS. However, after adjustment for potential confounders this association was no longer significant. If these findings are confirmed in larger studies, SUVmean could potentially be used (in addition to the number of positive nodes, tumour size and extranodal growth) as a factor in deciding on adjuvant systemic treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-012-2182-0) contains supplementary material, which is available to authorized users.

FDG-PET parameters as prognostic factor in esophageal cancer patients: a review

BACKGROUND

(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) has been used extensively to explore whether FDG Uptake can be used to provide prognostic information for esophageal cancer patients. The aim of the present review is to evaluate the literature available to date concerning the potential prognostic value of FDG uptake in esophageal cancer patients, in terms of absolute pretreatment values and of decrease in FDG uptake during or after neoadjuvant therapy.

METHODS

A computer-aided search of the English language literature concerning esophageal cancer and standardized uptake values was performed. This search focused on clinical studies evaluating the prognostic value of FDG uptake as an absolute value or the decrease in FDG uptake and using overall mortality and/or disease-related mortality as an end point.

RESULTS

In total, 31 studies met the predefined criteria. Two main groups were identified based on the tested prognostic parameter: (1) FDG uptake and (2) decrease in FDG uptake. Most studies showed that pretreatment FDG uptake and postneoadjuvant treatment FDG uptake, as absolute values, are predictors for survival in univariate analysis. Moreover, early decrease in FDG uptake during neoadjuvant therapy is predictive for response and survival in most studies described. However, late decrease in FDG uptake after completion of neoadjuvant therapy was predictive for pathological response and survival in only 2 of 6 studies.

CONCLUSIONS

Measuring decrease in FDG uptake early during neoadjuvant therapy is most appealing, moreover because the observed range of values expressed as relative decrease to discriminate responding from nonresponding patients is very small. At present inter-institutional comparison of results is difficult because several different normalization factors for FDG uptake are in use. Therefore, more research focusing on standardization of protocols and inter-institutional differences should be performed, before a PET-guided algorithm can be universally advocated.

First-line erlotinib and bevacizumab in patients with locally advanced and/or metastatic non-small-cell lung cancer: a phase II study including molecular imaging

BACKGROUND

Both bevacizumab and erlotinib have clinical activity in non-small-cell lung cancer (NSCLC). Preclinical data suggest synergistic activity.

PATIENTS AND METHODS

Chemonaive patients with stage IIIb or IV non-squamous NSCLC were treated with bevacizumab 15 mg/kg every 3 weeks and erlotinib 150 mg daily until progression. Primary end point was non-progression rate (NPR) at 6 weeks. Tumor response was measured with computed tomography, 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG-PET) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). KRAS and EGFR mutations were assessed in tumor samples.

RESULTS

Forty-seven patients were included. Median follow-up was 15.2 months. NPR at 6 weeks was 75%. Median progression-free survival (PFS) was 3.8 [95% confidence interval (CI) 2.3-5.4] months and median overall survival (OS) was 6.9 (95% CI 5.5-8.4) months. Toxicity was mainly mild. The presence of KRAS (n = 10) or EGFR mutations (n = 5) did not influence outcome. After 3 weeks of treatment, >20% decrease in standard uptake value as measured with positron emission tomography predicted for longer PFS (9.7 versus 2.8 months; P = 0.01) and >40% decrease in K(trans) as assessed by DCE-MRI did not predict for longer PFS.

CONCLUSIONS

First-line treatment with bevacizumab and erlotinib in stage IIIb/IV NSCLC resulted in an NPR of 75%. OS was however disappointing. Early response evaluation with FDG-PET is the best predictive test for PFS.

[Potential clinical applications of the sentinel node procedure in oral cancer]

In cases of oral cavity cancer a reliable diagnostic technique is needed to detect occult regional lymph node metastases and to avoid futile elective neck dissections as well as undertreatment. The first studies revealed a sensitivity of 94%. However, the sentinel node procedure is not yet a routinely performed procedure in oral cancer.

Importance of fluorodeoxyglucose-positron emission tomography (FDG-PET) and endoscopic ultrasonography parameters in predicting survival following surgery for esophageal cancer

BACKGROUND AND STUDY AIMS

To assess the prognostic importance of standardized uptake value (SUV) for 18F-fluorodeoxyglucose (FDG) at positron emission tomography (PET) and of EUS parameters, in esophageal cancer patients primarily treated by surgery.

PATIENTS AND METHODS

Between October 2002 and August 2004 a prospective cohort study involved 125 patients, with histologically proven cancer of the esophagus, without evidence of distant metastases or locally irresectable disease based on extensive preoperative work-up, and fit to undergo major surgery. Follow-up was complete until October 2006, ensuring a minimal potential follow-up of 25 months.

RESULTS

The median SUV was 0.27 (interquartile range 0.13 - 0.45), and was used as cutoff value between high (n = 62) and low (n = 63) SUV. Patients with a high SUV had a significantly worse disease-specific survival compared with patients with a low SUV (P = 0.04). Tumor location (P = 0.005), EUS T stage (P < 0.001), EUS N stage (P = 0.006) and clinical stage (P < 0.006) were also associated with disease-specific survival. However, in multivariate analysis only EUS T stage appeared to be of independent prognostic significance (P = 0.007).

CONCLUSION

In esophageal cancer patients, EUS T stage, EUS N stage, location and SUV of the primary tumor are pretreatment factors that are associated with disease-specific survival. However, only EUS T stage is an independent prognostic factor.

The role of (124)I-PET in diagnosis and treatment of thyroid carcinoma

Iodine-124 is a positron-emitting iodine isotope, enabling measurement of iodine uptake using positron emission tomography (PET). There is a number of situations where the use of (124)I-PET/computed tomography (CT) can improve the current clinical practice in the diagnosis and treatment of thyroid cancer. Firstly, (124)I-PET/CT can aid in the staging of patients, because of better detection of metastatic disease and measurement of metabolic tumour volume, and thus separate low-risk from high risk patients. Secondly, the much higher sensitivity and spatial resolution of PET compared to gamma scintigraphy can also improve detection of recurrent disease. Furthermore, (124)I-PET can be used for patient-specific radioiodine therapy radiation dosimetry. Simultaneous administration of the therapeutic dose of (131)I and a tracer dose of (124)I allows for accurate measurement of iodine uptake during therapy. The decay scheme of (124)I, with few positrons and many gamma rays emitted per decay, often simultaneously, poses a challenge to quantitative PET imaging. Improved correction methods and the use of last-generation PET/CT scanners with faster electronics and better energy resolution can overcome this.

[The value of positron emission tomography in the diagnosis and treatment of oesophageal cancer]

Fludeoxyglucose positron emission tomography (FDG-PET) is a noninvasive imaging technique that applies the glucose metabolism to visualise the metabolic activity ofa tumour. FDG-PET might improve the selection of potentially curable patients with oesophageal cancer in addition to state-of-the-art conventional work-up (e.g. endoscopic ultrasonography and spiral CT). The additional value however is only 4% for all patients, and 7% in patients with stage III-IV disease. Moreover, the additional costs of FDG-PET are not compensated by the cost reduction ofprevented surgery. To improve the outcome of patients with oesophageal cancer the value ofneoadjuvant chemo- and/or radiotherapy is being investigated. FDG-PET seems to be a promising tool for the early assessment of response to neoadjuvant therapy. In case of non-response the ineffective neoadjuvant therapy can be stopped without further delaying appropriate surgery. FDG-PET might be able to improve the prediction of prognosis, in addition to commonly used histopathological factors.

Hexokinase III, cyclin A and galectin-3 are overexpressed in malignant follicular thyroid nodules

BACKGROUND

Distinguishing malignant thyroid nodules in patients with follicular cytology by fine-needle aspiration (FNA) remains problematic. The large majority of thyroid nodules (> 85%) are overtreated. Therefore, a clear need exists to develop more accurate initial diagnostic tests for follicular thyroid nodules. Galectin-3 is the most recent promising marker to aid discrimination between benign and malignant thyroid lesions; however, this biomarker can be absent in follicular malignancies.

AIMS

This study was undertaken to determine whether additional biomarkers can help to discriminate between benign and malignant thyroid nodules.

METHODS

Surgical specimens of 36 patients with benign (n = 12) and malignant (n = 24) thyroid nodules showing follicular cytology were assessed by immunohistochemistry for the expression of galectin-3 and novel biomarkers.

RESULTS

Expression of hexokinase III (HK III) (P = 0.000) cyclin A (P = 0.002) and galectin-3 (P = 0.003) differed significantly between benign and malignant thyroid nodules. HK III had a sensitivity of 79% [95% confidence interval (CI) 60-91] and a specificity of 100% (95% CI 76-100) in predicting malignancy. Galectin-3 had a sensitivity of 79% (95% CI 56-91) and a specificity of 75% (95% CI 47-91) in predicting malignancy. Combining HK III, cyclin A and galectin-3 in a parallel test increased the sensitivity to 96% (95% CI 80-99) while the specificity remained at a high level of 75% (95% CI 47-91). Leave-one-out cross-validation demonstrated a stable predictive validity of a model based on HK III, cyclin A and galectin-3.

CONCLUSIONS

In this study, we have demonstrated that in addition to galectin-3, HK III and cyclin A profiles could be important biomarkers in predicting malignancy in follicular thyroid nodules. The use of these biomarkers may allow an accurate preoperative diagnosis of thyroid cancer, which can be cost saving and may avoid serious morbidity such as vocal cord paralysis. The value of the suggested biomarkers warrants further evaluation in a large prospective study on cytological samples of follicular thyroid nodules.

Evaluation of pulmonary nodules: comparison of a prototype dual crystal (LSO/NAI) dual head coincidence camera and full ring positron emission tomography (PET)

PURPOSE

To determine the concordance of a prototype dual head coincidence camera (LSO-PS) and full ring PET (BGO-PET) using (18)F-fluorodeoxyglucose (FDG) in the evaluation of pulmonary nodules (PNs).

MATERIALS AND METHODS

Patients referred for evaluation of < or =3 PNs (< or =3 cm diameter) were prospectively studied on the same day with both BGO-PET and LSO-PS. Imaging was performed at 60 and 120 min after injection of 370MBq FDG, respectively. Images were independently interpreted by four observers with each observer blinded to the other modality for the same patient. Lesions were scored in terms of relative intensity versus background. Non-attenuation corrected (nonAC) BGO-PET was used as the reference test.

RESULTS

Forty-seven patients with 54 PNs (mean diameter 1.7 cm, S.D. 0.7) were included. Twelve nodules were in the < or =1.0 cm - 27 in the 1.1-2.0 cm - and 15 in the 2.1-3.0 cm range. Interobserver agreement was similar for both FDG imaging modalities. Using a sensitive assessment strategy with LSO-PS (> or = faint intensity deemed positive), there was a 97% (38/39, 95%CI 87-100%) concordance with BGO-PET and one false positive case with LSO-PS. Conservative reading (moderate or intense intensity deemed positive) resulted in a 92% (36/39, 95%CI 80-97%) concordance with BGO-PET, without false positives. The only lesion missed by LSO-PS using both assessment strategies involved a nodule 1.5 cm diameter that demonstrated moderate increased FDG uptake on BGO-PET.

CONCLUSION

Depending on the test positivity criteria, LSO-PS demonstrates a high concordance (92-97%) with nonAC BGO-PET for the characterization of pulmonary nodules.

Impact of [18F]fluorodeoxyglucose positron emission tomography on surgical management of melanoma patients

Background

Several studies have shown adequate sensitivity and specificity of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the detection of metastases from melanoma, but few have addressed its impact on treatment. The aim of this retrospective study was to assess the impact of FDG-PET on treatment of melanoma in three Dutch university medical centres.

Methods

The medical records of 257 patients were reviewed. The indications for FDG-PET and findings were recorded. Unexpected findings of suspected (pre)malignant tumours other than melanoma were assessed. Treatment plans before and after FDG-PET were recorded and analysed to evaluate changes in disease management.

Results

Most scans (71·2 per cent) were requested for staging, mainly to detect distant metastases in patients with stage III disease. Overall, 56 patients (21·8 per cent) were upstaged as a result of PET. In 44 patients (17·1 per cent) treatment was changed, usually from surgery to systemic treatment in patients with stage III disease. Unexpected tumours were detected (mainly colorectal) in 11 patients (4·3 per cent).

Conclusion

FDG-PET is most valuable in patients with stage III melanoma for detection of distant metastases and identification of candidates for surgery and/or systemic treatment. Unexpected FDG-PET findings should not be disregarded, as (pre)malignant, clinically relevant, tumours may be identified.

Screening for distant metastases in patients with head and neck cancer: what is the current clinical practice?

OBJECTIVES

The detection of distant metastases during screening influences the choice of treatment in patients with head and neck squamous cell carcinoma (HNSCC). There is no consensus on the diagnostic technique that has to be used nor on the subgroup of HNSCC patients that may benefit from screening.

DESIGN

Questionnaire on current practice concerning the diagnostic work-up in HNSCC patients for screening for distant metastases.

PARTICIPANTS

Investigators in the 12 otolaryngology / head and neck and seven oromaxillofacial departments treating head and neck cancer in the Netherlands.

RESULTS

The response rate was 100%. Indications for screening were cervical lymph node metastases (63%), mutilating surgery (58%), locoregional recurrence (47%), advanced T-stage (32%), second primary tumour (21%). Diagnostic techniques routinely used for screening besides chest X-ray were chest CT (84%), liver ultrasound (53%), liver CT (16%) and bone scintigraphy (42%). Forty-two per cent of the clinicians were not satisfied with the current methods of screening.

CONCLUSION

This survey shows a substantial variation in indications and diagnostic techniques used for screening for distant metastases between the major institutions treating head and neck cancer in the Netherlands. There is a need for guidelines for screening for distant metastases in patients with head and neck cancer.

Accuracy of diagnostic imaging techniques in the diagnosis of aseptic loosening of the femoral component of a hip prosthesis

In this meta-analysis we included 32 English-language articles published between January 1975 and June 2004 on the diagnostic performance of plain radiography, subtraction arthrography, nuclear arthrography and bone scintigraphy in detecting aseptic loosening of the femoral component, using criteria based on the Cochrane systematic review of screening and diagnostic tests.

The mean sensitivity and specificity were, respectively, 82% (95% confidence interval (CI) 76 to 87) and 81% (95% CI 73 to 87) for plain radiography and 85% (95% CI 75 to 91) and 83% (95% CI 75 to 89) for nuclear arthrography. Pooled sensitivity and specificity were, respectively, 86% (95% CI 74 to 93) and 85% (95% CI 77 to 91) for subtraction arthrography and 85% (95% CI 79 to 89) and 72% (95% CI 64 to 79) for bone scintigraphy. Although the diagnostic performance of the imaging techniques was not significantly different, plain radiography and bone scintigraphy are preferred for the assessment of a femoral component because of their efficacy and lower risk of patient morbidity.

[18F]fluorodeoxyglucose uptake in recurrent thyroid cancer is related to hexokinase i expression in the primary tumor

Patients suspected of recurrent differentiated thyroid cancer (DTC) may require "blind" (131)I therapy, with the disadvantage of unpredictable efficacy and toxicity. Alternatively, positron emission tomography (PET) with [(18)F]fluorodeoxyglucose ((18)FDG) can document the recurrence, thereby rationalizing therapeutic options. This study compared (18)FDG uptake in vivo with biomarkers expected to be involved in the underlying biological mechanisms. Additionally, we investigated whether such features were present in the primary tumors. Preoperatively, 19 patients with recurrent DTC underwent PET. (18)FDG uptake was compared with histological and immunohistochemical features in surgical specimens of recurrent and primary tumor. Thirteen of 19 recurrences were positive at PET, and (18)FDG uptake was associated with the expression of hexokinase type I (HK I; P = 0.011). All lesions with HK I overexpression were positive on (18)FDG PET. HK I expression in the original primary tumor and the metastases was similar in 82% (rho = 0.648; P = 0.005). In suspected recurrent thyroid cancer, stratification for (18)FDG PET may benefit from pretest immunohistochemical analysis of HK I of the primary tumor, as HK I negativity indicates a low likelihood of PET positivity.

In search of an unknown primary tumour presenting with extracervical metastases: the diagnostic performance of FDG-PET

A retrospective study was carried out to determine the performance of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with unknown primary tumours presenting with metastases external to the neck. All patients referred to an academic PET centre (July, 1997 to December, 2000) presenting with an extracervical metastasis and no prior systemic therapy were eligible. The minimum follow-up period was 11 months. From 63 eligible cases, known metastases were FDG avid in all but one neuroendocrine process. PET scans were retrospectively classified as positive for a primary tumour (n=29), i.e. revealing at least one anatomical site suspected to be the primary tumour. This was confirmed in 16, either by histology (n=10) or radiological and clinical follow-up (n=6). There were four false positive cases. In nine patients, the primary tumour was never confirmed. Of the remaining 33 negative PET scans the primary tumour was clinically not found in 18. Follow-up and additional pathology investigations demonstrated the primary tumour in 15. A survey on clinical usefulness of PET (response rate 83%) suggested that PET positively contributed to diagnostic understanding in 29 of 52 evaluable cases. Applied late in the diagnostic trajectory, approximately four patients need to be scanned by PET in order to find one primary tumour. However, in addition to direct demonstration of unknown primaries, there appears to be a positive effect on the diagnostic work-up of these patients of a similar magnitude.

[Surgery and follow-up 131I therapy in patients with differentiated thyroid carcinoma in the south-east of the Netherlands, 1983-1996, compliance with the 1987 consensus guidelines: additional data]

In a previous study using data from the regional cancer registry of the Comprehensive Cancer Centre South, Eindhoven, The Netherlands, we concluded that in the majority of cases surgical treatment was in accordance with the consensus recommendations, but that about 40% of patients with differentiated thyroid cancer from a number of regional hospitals had not been referred for 131I therapy. However, in a subsequent study using patient data from these hospitals, it became clear that almost all patients had in fact been referred for therapy but to centres outside the 131I therapy region. The conclusion of the study should therefore be altered: the great majority of patients with differentiated thyroid cancer in the south-east of The Netherlands (1983-96) were referred for 131I treatment and therefore the primary surgical and the follow-up treatment complied with the 1987 consensus guidelines.

Fluorine-18 fluorodeoxyglucose positron emission tomography (PET) to detect vital retinoblastoma in the eye: preliminary experience

BACKGROUND/AIMS

To report our first experience with FDG-PET in the detection of vital retinoblastoma.

METHODS

Four newly diagnosed retinoblastoma patients, two treated retinoblastoma patients, and four control patients were enrolled in this pilot study. F18-FDG uptake was assessed in the light of clinical and histopathological features.

RESULTS

PET discriminated between new patients and controls, although tumor uptake varied widely. PET added no useful information with regard to possible vital tissue in tumor scars in the eye of the two treated retinoblastoma patients. Moreover, PET findings did not correlate with clinical or histopathological features.

CONCLUSION

Based on this small pilot study, F18-PET shows little promise in the detection of retinoblastoma. More research on other radiofarmacons is recommended.

Staging in patients with locoregionally recurrent breast cancer: current practice and prospects for positron emission tomography

The aim of this study was to describe the extent and yield of daily clinical practice when staging patients with a locoregional recurrence (LRR) of breast carcinoma and to explore the prospects for positron emission tomography (PET). The population-based Eindhoven Cancer Registry was used to select all breast cancer patients in the southeast of the Netherlands with a first episode of LRR between January 1, 1994 and June 30, 2000 (n = 175). Additional data concerning staging procedures and follow-up were collected from the medical records. Furthermore, we asked 77 physicians (response: 75%) about their opinions on staging procedures and actual treatment policy. At LRR presentation, 16% of patients were found to have distant metastases. An additional 24% were diagnosed with distant metastases within 18 months. The questionnaire revealed that 33% of clinicians thought that the sensitivity of conventional imaging techniques was too low. We tend to conclude that in daily clinical practice there is a need for more sensitive dissemination tests for patients with a LRR of breast cancer.

Non-invasive diagnostic work-up of patients with clinically suspected pulmonary embolism; results of a management study

BACKGROUND

Clinicians often deviate from the recommended algorithm for the diagnosis of pulmonary embolism consisting of ventilation-perfusion scintigraphy and pulmonary angiography.

OBJECTIVES

To assess the safety and feasibility of a diagnostic algorithm which reduces the need for lung scintigraphy and avoids the use of angiography.

PATIENTS AND METHODS

Consecutive patients with a clinical suspicion of pulmonary embolism were prospectively investigated according to an algorithm in which the diagnosis of pulmonary embolism was excluded after a low clinical probability estimate and a normal d-dimer test result, a normal perfusion scintigraphy result, or a non-high probability scintigraphy result in combination with normal serial ultrasonography of the legs. In these patients anticoagulant treatment was withheld and they were followed up for 3 months to record possible thromboembolic events. During the study period, 923 consecutive patients were seen, of whom 292 were excluded because of predefined criteria.

RESULTS

Of the 631 included patients, the diagnosis was refuted on the basis of a low clinical probability estimate and a normal d-dimer test result (95 patients), normal perfusion scintigraphy (161 patients) and non-high probability lung scintigraphy followed by normal serial ultrasonography (210 patients). Of these 466 patients, venous thromboembolic complications during follow-up occurred in six (complication rate 1.3%, 95% confidence interval 0.5, 2.8). The diagnostic protocol was completed in 92% of all included patients.

CONCLUSION

The diagnosis of pulmonary embolism can be safely ruled out by a non-invasive algorithm consisting of d-dimer testing combined with a clinical probability estimate, lung scintigraphy, or serial ultrasonography of the legs (in case of non-diagnostic lung scintigraphy).

Towards a minimally invasive staging strategy in NSCLC: analysis of PET positive mediastinal lesions by EUS-FNA

STUDY OBJECTIVE

To asses the value of endoscopic ultrasound guided fine needle aspiration (EUS-FNA) in the nodal staging of patients with (suspected) non-small cell lung cancer (NSCLC) and a (18)FDG positron emission tomography (PET) scan suspect for N2/N3 mediastinal lymph node (MLN) metastases.

BACKGROUND

Due to the imperfect specificity of positron emission tomography, PET positive MLN should be biopsied in order to confirm or rule out metastasis. Currently, invasive surgical diagnostic techniques such as mediastinoscopy/-tomy are standard procedures to obtain MLN tissue. The minimally invasive technique of EUS-FNA has a high diagnostic accuracy (90-94%) for the analysis of MLN in patients with enlarged MLN on computed tomography of the chest (CT).

DESIGN AND PATIENTS

Thirty-six patients with proven n=26 or suspected n=10 non-small cell lung cancer and a PET scan suspect for N2/N3 lymph node metastases underwent EUS-FNA. When EUS-FNA did not confirm metastasis and the PET lesion was within reach of mediastinoscopy, a mediastinoscopy was performed. EUS-FNA negative patients with PET lesions beyond the reach of mediastinoscopy or those with a negative mediastinoscopy were referred for surgical resection of the tumour and MLN sampling or dissection.

RESULTS

EUS-FNA confirmed N2/N3 disease in 25 of the 36 patients (69%) and was highly suspicious in one. In the remaining 10 patients, one PET positive and one PET negative N2 metastasis was detected at thoracotomy. The PPV, NPV, sensitivity, specificity and accuracy of EUS-FNA in analysing PET positive MLN were 100%, 80%, 93%, 100% and 94%, respectively. No complications of EUS-FNA were recorded.

CONCLUSIONS AND SIGNIFICANCE

EUS-FNA yields minimally invasive confirmation of MLN metastases in 69% of the patients with potential mediastinal involvement at FDG PET. The combination of PET and EUS-FNA might qualify as a minimally invasive staging strategy for NSCLC.