Prognostic value of post-treatment 18F-FDG PET/CT for advanced head and neck cancer after combined intra-arterial chemotherapy and radiotherapy简

Objective：To clarify the prognostic value of post-treatment 18F-fluorodeoxyglucose （FDG） positron emission tomography （PET）/computed tomography （CT） in patients with advanced head and neck squamous cell carcinoma （HNSCC） after combined intra-arterial chemotherapy and radiotherapy （IACR）.Methods：Thirty-six patients with HNSCC who underwent IACR were recruited.The period from the end of IACR to the last post-treatment 18F-FDG PET/CT examination was 8-12 weeks.Both patient-based and lesion-based analyses were used to evaluate the PET/CT images.For lesion-based analysis,36 regions （12 lesions of recurrences and 24 scars at primary sites） were selected.The Kaplan-Meier method was used to assess the overall survival （OS） stratified by 18F-FDG uptake or visual interpretation results.Results：Twelve patients with recurrence were identified by six months after IACR.The sensitivity and specificity in the patient-based analysis were 67％ （8/12） and 88％ （21/24）,respectively.The mean OS was estimated to be 12.1 months （95％ CI,6.3-18.0 months） for the higher maximum standardized uptake value （SUVmax） group （n=7） and 44.6 months （95％ CI,39.9-49.3 months） for the lower SUVmax group （n=29）.OS in the higher SUVmax group （cut-off point,6.1） or positive visual interpretation group was significantly shorter than that in the lower SUVmax or negative visual interpretation group （P＜0.001 and P＜0.05,respectively）.Conclusions：The SUVmax and visual interpretation of HNSCC on post-IACR 18F-FDG PET/CT can provide prognostic survival estimates.     

Usefulness of 18-F FDG PET/CT in the pre-treatment evaluation of thymic epithelial neoplasms

Background

To assess the usefulness of ¹⁸fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for differentiating the grade of malignancy of thymic epithelial neoplasm, and to determine whether ¹⁸F-FDG PET/CT can have a role in pretreatment evaluation and possibly modify treatment strategy.

Materials and methods

The data of 26 consecutive patients (14 males and 12 females) diagnosed with a thymic epithelial neoplasm were prospectively collected and analyzed retrospectively. All patients underwent standard clinical assessment and ¹⁸F-FDG PET/CT. The patients were divided into two subgroups according to a simplified histologic classification: low-risk thymoma (types A, AB and B1) and high-risk thymoma (types B2, B3 and C). The maximum standardized uptake value (SUV_max) of the tumor, the mean SUV of mediastinum, and the tumor/mediastinum (T/M) ratio (ratio of peak SUV of the tumor to mean SUV of mediastinum) were compared to determine whether the two subgroups (low-risk versus high-risk tumors) could be distinguished by ¹⁸F-FDG PET/CT, and to test for possible correlations between ¹⁸F-FDG uptake and disease stage.

Results

There was a strong statistical correlation between SUV_max and patient subgroup and between SUV_max and disease stage, and an even stronger correlation between SUV_max and patient subgroup and the T/M ratio; a T/M ratio of 2.75 emerged as the cut-off value for differentiating between low-risk and high-risk thymomas.

Conclusions

¹⁸F-FDG PET/CT can be used a “metabolic biopsy” to divide thymic epithelial neoplasm into two subgroups of high and low risk and is useful in pretreatment staging.     

Thyroid lesions incidentally detected by 18F-FDG PET-CT — a two centre retrospective study

Background.

Incidental ¹⁸F-FDG uptake in the thyroid on PET-CT examinations represents a diagnostic challenge. The maximal standardized uptake value (SUV_max) is one possible parameter that can help in distinguishing between benign and malignant thyroid PET lesions.

Patients and methods.

We retrospectively evaluated ¹⁸F-FDG PET-CT examinations of 5,911 patients performed at two different medical centres from 2010 to 2011. If pathologically increased activity was accidentally detected in the thyroid, the SUV_max of the thyroid lesion was calculated. Patients with incidental ¹⁸F-FDG uptake in the thyroid were instructed to visit a thyroidologist, who performed further investigation including fine needle aspiration cytology (FNAC) if needed. Lesions deemed suspicious after FNAC were referred for surgery.

Results.

Incidental ¹⁸F-FDG uptake in the thyroid was found in 3.89% — in 230 out of 5,911 patients investigated on PET-CT. Malignant thyroid lesions (represented with focal thyroid uptake) were detected in 10 of 66 patients (in 15.2%). In the first medical centre the SUV_max of 36 benign lesions was 5.6 ± 2.8 compared to 15.8 ± 9.2 of 5 malignant lesions (p < 0.001). In the second centre the SUV_max of 20 benign lesions was 3.7 ± 2.2 compared to 5.1 ± 2.3 of 5 malignant lesions (p = 0.217). All 29 further investigated diffuse thyroid lesions were benign.

Conclusions.

Incidental ¹⁸F-FDG uptake in the thyroid was found in 3.89% of patients who had a PET-CT examination. Only focal thyroid uptake represented a malignant lesion in our study — in 15.2% of all focal thyroid lesions. SUV_max should only serve as one of several parameters that alert the clinician on the possibility of thyroid malignancy.     

Evaluation of children with craniopharyngioma using carbon-11 methionine PET prior to proton therapy

Background

Fluorine-18 (¹⁸F) fluorodeoxyglucose (FDG) positron emission tomography (PET) is limited in its evaluation of brain tumors due to the high basal activity of the cerebral cortex and white matter. Carbon-11 methionine (¹¹C MET) has little uptake under normal conditions. We prospectively investigated the uptake of ¹⁸F FDG and ¹¹C MET PET in patients with craniopharyngioma prior to proton therapy.

Methods

Ten patients newly diagnosed with craniopharyngioma underwent PET imaging using ¹⁸F FDG and ¹¹C MET. PET and MRI studies were registered to help identify tumor volume. Measurements of maximum standardized uptake value (SUV_max) were taken of the tumor and compared with noninvolved left frontal background white matter using a paired t-test. Uptake was graded using a 4-point scale.

Results

Median patient age was 9 years (range 5–19). Seven patients were diagnosed by pathology, 1 by cyst fluid aspiration, and 2 by neuroimaging. Median FDG SUV_max for tumor and background were 2.65 and 3.2, respectively. Median MET SUV_max for tumor and background were 2.2 and 1, respectively. There was a significant difference between MET tumor SUV_max and MET background SUV_max (P = .0001). The difference between FDG tumor SUV_max and FDG background SUV_max was not significant (P = .3672).

Conclusion

¹¹C MET PET uptake is significantly greater within the tumor compared with noninvolved background white matter, making it more useful than FDG PET in identifying active tumor in patients with craniopharyngioma. Future work will focus on using ¹¹C MET PET to discriminate between active and inactive tumor after irradiation.     

The value of primary tumor <Superscript>18</Superscript>F-FDG uptake on preoperative PET/CT for predicting intratumoral lymphatic invasion and axillary nodal metastasis

Background

The preoperative evaluation of axillary lymph node (LN) status is important for prognostic prediction of breast cancer. We investigated the ability of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) to predict intratumoral lymphatic invasion and axillary LN metastasis.

Methods

The preoperative ¹⁸F-FDG PET/CT images and pathologic reports for 428 breast cancer patients between January 2003 and December 2008 were evaluated retrospectively. The maximum standardized uptake value (SUV_max) of the primary tumor on ¹⁸F-FDG PET/CT, the degree of lymphatic invasion, and axillary LN metastasis identified by pathologic reports were assessed. Univariate and multivariate logistic regression analyses were performed to identify the significant features of the primary tumor that were associated with pathologically confirmed axillary LN metastasis.

Results

The mean SUV_max of primary tumors with lymphatic invasion was higher than that of tumors without lymphatic invasion (5.13 ± 3.49 vs. 3.00 ± 2.47; p < 0.0001). The mean SUV_max of primary tumors with pathologically confirmed axillary LN metastasis was higher than that of tumors without LN metastasis (4.93 ± 3.32 vs. 3.22 ± 2.78; p < 0.0001). The degree of lymphatic invasion correlated strongly with axillary LN metastasis (p = 0.0001). Multiple logistic regression analysis showed that the high SUV_max of the primary tumor (>2.8), the high SUV_max of the axillary LN (>0.72) and the degree of lymphatic invasion were significant predictive factors of the development of axillary LN metastasis.

Conclusion

Breast cancer patients with higher primary tumor ¹⁸F-FDG uptake are at higher risk of concurrent intratumoral lymphatic invasion and axillary LN metastasis.

     

18F-FDG PET/CT as a diagnostic tool in patients with extracervical carcinoma of unknown primary site: a literature review

Background.

Carcinoma of unknown primary (CUP) represents a heterogeneous group of metastatic malignancies for which no primary tumor site can be identified after extensive diagnostic workup. Failure to identify the primary site may negatively influence patient management. The aim of this review was to evaluate ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) as a diagnostic tool in patients with extracervical CUP.

Materials and Methods.

A comprehensive literature search was performed and four publications were identified (involving 152 patients) evaluating ¹⁸F-FDG PET/CT in CUP patients with extracervical metastases. All studies were retrospective and heterogeneous in inclusion criteria, study design, and diagnostic workup prior to ¹⁸F-FDG PET/CT.

Results.

¹⁸F-FDG PET/CT detected the primary tumor in 39.5% of patients with extracervical CUP. The lung was the most commonly detected primary tumor site (∼50%). The pooled estimates of sensitivity, specificity, and accuracy of ¹⁸F-FDG PET/CT in the detection of the primary tumor site were 87%, 88%, and 87.5%, respectively.

Conclusions.

The present review of currently available data indicates that ¹⁸F-FDG PET/CT might contribute to the identification of the primary tumor site in extracervical CUP. However, prospective studies with more uniform inclusion criteria are required to evaluate the exact value of this diagnostic tool.     

Characteristics of thyroid incidentalomas detected by pre-treatment [18F]FDG PET or PET/CT in patients with cervical cancer

Objective

Considering the increased use of [¹⁸F]FDG PET or PET/CT, the clinical significance of thyroid incidentalomas is the subject of controversy. The aim of this study was to determine the incidence of malignancies associated with thyroid incidentalomas detected by pre-treatment PET or PET/CT in patients with cervical cancer.

Methods

We retrospectively reviewed the medical records of patients with cervical cancer who had thyroid incidentalomas detected by pre-treatment PET or PET/CT and were treated at our institute between January 2001 and December 2009.

Results

Of 327 patients who underwent pre-treatment PET or PET/CT, 33 patients had thyroid incidentalomas (10.1%) and 4 patients were diagnosed with thyroid malignancies by percutaneous needle aspiration (PCNA) or surgery. To put it concretely, of 33 patients with thyroid incidentaloma, 16 patients had a diffuse uptake and 17 patients had a focal uptake. Four of 17 patients with focal uptake were diagnosed with thyroid malignancies (23.5%). One patient with a focal uptake had an atypical cell based on PCNA, but did not undergo additional studies. The mean SUV_max of thyroid malignancies did not differ from that of benign thyroid diseases.

Conclusion

Thyroid incidentalomas are frequently detected by pre-treatment PET or PET/CT in patients with cervical cancer. Focal uptake on PET or PET/CT has a high risk of thyroid cancer.     

Metabolic Characteristics of Advanced Biliary Tract Cancer Using 18F‐Fluorodeoxyglucose Positron Emission Tomography and Their Clinical Implications

Background.

In advanced biliary tract cancer (BTC), the metabolic landscape has not been evaluated by ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) yet. Furthermore, reports of the clinical implications of these metabolic features are limited. We aimed to evaluate the metabolic features and their clinical relevance in advanced BTC using ¹⁸F-FDG PET.

Patients and Methods.

We consecutively enrolled patients with advanced BTC who underwent ¹⁸F-FDG PET prior to palliative chemotherapy between 2003 and 2013. We evaluated the findings of PET, such as SUV_max, the number of lesions and organs with FDG uptake, pathologic findings, and clinical outcomes.

Results.

A total of 106 patients were enrolled: (53 intrahepatic cholangiocarcinoma [ICC], 7 extrahepatic BTC, 30 gallbladder cancer [GB Ca], and 16 ampulla of Vater cancer [AoV Ca]). The median SUV_max differed according to the primary origin (ICC, 9.10; extrahepatic BTC, 5.90; GB Ca, 9.10; and AoV Ca, 6.37; p = .008) and histologic differentiation (well differentiated, 4.95; moderately differentiated, 6.60; poorly differentiated, 14.50; p = .004). Patients in the high metabolic group (SUV_max of ≥7.5) had more poorly differentiated histology and more organs and lesions with FDG uptake than did those in the low metabolic group (SUV_max of <7.5). The low metabolic group had a significantly longer OS (11.4 vs. 7.4 months, p = .007) and PFS (6.6 vs. 4.3 months, p = .024) than high metabolic group. In multivariate analysis, SUV_max was a significant prognostic factor for overall survival (OS; p = .047) and progression-free survival (PFS; p = .039).

Conclusion.

Metabolic characteristics of advanced BTC differ according to primary origin and histology. These metabolic features could be prognostic factors for OS and PFS in advanced BTC.

Implications for Practice:

The metabolic landscape of advanced biliary tract cancer and its clinical meanings have not yet been comprehensively studied. This study shows that metabolic characteristics of advanced biliary tract cancer differ significantly according to primary origin and histology. Moreover, this metabolic activity is associated with patients’ outcomes, including overall survival and progression-free survival. This study supports tumor heterogeneity in terms of cancer metabolism in biliary tract cancer.     

Evaluation of FLT-PET-CT as an imaging biomarker of proliferation in primary breast cancer

Background:

[¹⁸F]fluorothymidine (FLT) has been proposed as a positron emission tomography (PET)-imaging biomarker of proliferation for breast cancer. The aim of this prospective study was to assess the feasibility of FLT-PET-CT as a technique for predicting the response to neoadjuvant chemotherapy (NAC) in primary breast cancer and to compare baseline FLT with Ki-67.

Methods:

Twenty women with primary breast cancer had a baseline FLT-PET-CT scan that was repeated before the second cycle of chemotherapy. Expression of Ki-67 in the diagnostic biopsy was quantified. From the FLT-PET-CT scans lesion maximum and mean standardised uptake values (SUV_max, SUV_mean) were calculated.

Results:

Mean baseline SUV_max was 7.3, and 4.62 post one cycle of NAC, representing a drop of 2.68 (36.3%). There was no significant association between baseline, post chemotherapy, or change in SUV_max and pathological response to NAC. There was a significant correlation between pre-chemotherapy Ki-67 and SUV_max of 0.604 (P=0.006).

Conclusions:

Baseline SUV_max measurements of FLT-PET-CT were significantly related to Ki-67 suggesting that it is a proliferation biomarker. However, in this series neither the baseline value nor the change in SUV_max after one cycle of NAC were able to predict response as most patients had a sizeable SUV_max reduction.     

Axillary Lymph Node-to-Primary Tumor Standard Uptake Value Ratio on Preoperative 18F-FDG PET/CT: A Prognostic Factor for Invasive Ductal Breast Cancer

Purpose

This study assessed the axillary lymph node (ALN)-to-primary tumor maximum standard uptake value (SUV_max) ratio (ALN/T SUV ratio) in invasive ductal breast cancer (IDC) on preoperative ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) to determine the effectiveness in predicting recurrence-free survival (RFS).

Methods

One hundred nineteen IDC patients (mean age, 50.5±10.5 years) with pathologically proven ALN involvement without distant metastasis and preoperative FDG PET/CT were enrolled in the study. SUV_max values of the ALN and primary tumor were obtained on FDG PET/CT, and ALN/T SUV ratio was calculated. Several factors were evaluated for their effectiveness in predicting RFS. These included several parameters on FDG PET/CT as well as several clinicopathological parameters: pathologic tumor/node stage; nuclear and histological grade; hormonal state; status with respect to human epidermal growth factor receptor 2, mindbomb E3 ubiquitin protein ligase 1 (MIB-1), and p53; primary tumor size; and ALN size.

Results

Among 119 patients with breast cancer, 17 patients (14.3%) experienced relapse during follow-up (mean follow-up, 28.4 months). The ALN/T SUV ratio of the group with disease recurrence was higher than that of the group without recurrence (0.97±1.60 and 0.45±0.40, respectively, p=0.005). Univariate analysis showed that the primary tumor SUV_max, ALN SUV_max, ALN/T SUV ratio, ALN status, nuclear and histological grade, estrogen receptor (ER) status, and MIB-1 status were predictors for RFS. Among these variables, ALN/T SUV ratio with hazard ratio of 4.20 (95% confidence interval [CI], 1.74-10.13) and ER status with hazard ratio of 4.33 (95% CI, 1.06-17.71) were predictors for RFS according to multivariate analysis (p=0.002 and p=0.042, respectively).

Conclusion

Our study demonstrated that ALN/T SUV ratio together with ER status was an independent factor for predicting relapse in IDC with metastatic ALN. ALN/T SUV ratio on preoperative FDG PET/CT may be a useful marker for selecting IDC patients that need adjunct treatment to prevent recurrence.     

Value of DCE-MRI and FDG-PET/CT in the prediction of response to preoperative chemotherapy with bevacizumab for colorectal liver metastases

Background:

The purpose of this study was to assess the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography computed tomography (FDG-PET/CT) for evaluation of response to chemotherapy and bevacizumab and for prediction of progression-free survival (PFS) in patients with metastatic colorectal cancer (mCRC) with potentially resectable liver lesions.

Methods:

A total of 19 mCRC patients were treated with FOLFOX/FOLFIRI and bevacizumab followed by surgery. Dynamic contrast-enhanced magnetic resonance imaging and FDG-PET/CT were performed before treatment and after cycle 5. PET results were quantified by calculating maximum standardised uptake value (SUV_max) whereas area under the enhancement curve (AUC), initial AUC (iAUC) and the endothelial transfer constant (K^trans) were used to quantify DCE-MRI. Pathological analysis of the resection specimen was performed, including measurement of microvessel density (MVD) and proliferation index.

Results:

Both AUC and iAUC were significantly decreased following bevacizumab therapy (median change of 22% (P=0.002) and 40% (P=0.001) for AUC and iAUC, respectively). Progression-free survival benefit was shown for patients with >40% reduction in K^trans (P=0.019). In the group of radiological responders, the median baseline SUV_max was 3.77 (IQR: 2.88–5.60) compared with 7.20 (IQR: 4.67–8.73) in nonresponders (P=0.021). A higher follow-up SUV_max was correlated with worse PFS (P=0.012). Median MVD was 10.9. Progression-free survival was significantly shorter in patients with an MVD greater than 10, compared with patients with lower MVD (10 months compared with 16 months, P=0.016).

Conclusion:

High relative decrease in K^trans, low follow-up SUV_max and low MVD are favourable prognostic factors for mCRC patients treated with bevacizumab before surgery.     

Prognostic significance of 18F-FDG PET/CT in patients with colorectal cancer liver metastases after hepatectomy

Introduction

Colorectal cancer liver metastasis (CRLM) can be cured with surgery. To improve survival, optimal selection of CRLM patients should be done cautiously, which may be facilitated by preoperative [F-18] fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT).

Dual PET/CT with F-DOPA and F-FDG in metastatic medullary thyroid carcinoma and rapidly increasing calcitonin levels: Comparison with conventional imaging

Background

To evaluate the role of a multi-imaging PET with ¹⁸F-DOPA and ¹⁸F-FDG in comparison with conventional imaging (CI) in recurrent medullary thyroid carcinoma (MTC).

Methods

18 MTC patients who had thyroidectomy were included; they presented with elevated and rapidly increasing calcitonin levels during follow up. CI had revealed metastatic deposits in 9 patients. Patients were referred to us for a PET/CT with ¹⁸F-DOPA and ¹⁸F-FDG. Histologic/cytologic confirmation of recurrent MTC was obtained in at least one PET-positive lesion in all patients.

Results

Foci of abnormal uptake were observed in 15 patients at ¹⁸F-DOPA and in 11 at ¹⁸F-FDG; 8 patients showed the same number of positive lesions with both tracers, 2 showed more lesions on ¹⁸F-FDG, 1 was positive at ¹⁸F-FDG alone and 5 at ¹⁸F-DOPA alone. In 3 patients with a DOPA-positive loco-regional relapse a re-operation with curative intent was offered. SUV_max values were higher for ¹⁸F-FDG compared to ¹⁸F-DOPA (mean 12.7 ± 4.1 vs. 5.5 ± 2.1, p < 0.05). Calcitonin was higher in PET-positive patients compared to PET negative ones, while no significant differences were observed between ¹⁸F-DOPA and ¹⁸F-FDG positive patients.

Conclusions

In MTC patients with rapidly increasing calcitonin levels during follow up, ¹⁸F-DOPA has a good sensitivity and a complementary role with ¹⁸F-FDG PET/CT in detecting metastatic deposits. In our experience, the sensitivity of a multi-imaging ¹⁸F-DOPA & ¹⁸F-FDG PET/CT approach is greater than that obtained with CI. The higher SUV_max values found with ¹⁸F-FDG in some patients may reflect more aggressive tumors.     

Incidental Breast Lesions Identified by 18F-FDG PET/CT: Which Clinical Variables Differentiate between Benign and Malignant Breast Lesions?

Purpose

The aim of our study was to evaluate the risk of malignancy and to determine which clinical variables differentiate between benign and malignant focal breast lesions found incidentally on ¹⁸F-flourodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT).

Methods

From March 2005 to October 2011, 21,224 women with no history of breast cancer underwent FDG PET/CT at three university-affiliated hospitals. We retrospectively identified 214 patients with incidental focal hypermetabolic breast lesions and grouped them into benign and malignant lesion groups. Of the 214 patients, 82 patients with 91 lesions were included in this study. All lesions were confirmed histologically or were assessed by follow-up imaging for greater than 2 years. The patient age, maximum standardized uptake value (SUV_max), lesion size on ultrasonography (US), and Breast Imaging-Reporting and Data System (BI-RADS) category on US in conjunction with mammography were compared between the groups. Multivariate logistic regression analysis was used to identify independent factors associated with malignancy.

Results

The risk of malignancy was 29.7% (27/91) in breast incidentalomas detected by FDG PET/CT. The univariate analysis showed that the patient age, SUV_max, tumor size, and BI-RADS category differed significantly between the malignant and benign groups. The multivariate analysis showed that the BI-RADS category was the only significant factor differentiating benign from malignant lesions (p=0.002).

Conclusion

BIRADS category based on US in conjunction with mammography was the only useful tool to differentiate between malignant and benign lesions in breast incidentalomas on FDG PET/CT.     

Prognostic value of preoperative intratumoral FDG uptake heterogeneity in early stage uterine cervical cancer

Objective

We investigated the prognostic value of intratumoral [¹⁸F]fluorodeoxyglucose (FDG) uptake heterogeneity (IFH) derived from positron emission tomography/computed tomography (PET/CT) in patients with cervical cancer.

Methods

Patients with uterine cervical cancer of the International Federation of Obstetrics and Gynecology (FIGO) stage IB to IIA were imaged with [¹⁸F]FDG PET/CT before radical surgery. PET/CT parameters such as maximum and average standardized uptake values (SUV_max and SUV_avg), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and IFH were assessed. Regression analyses were used to identify clinicopathological and imaging variables associated with progression-free survival (PFS).

Results

We retrospectively reviewed clinical data of 85 eligible patients. Median PFS was 32 months (range, 6 to 83 months), with recurrence observed in 14 patients (16.5%). IFH at an SUV of 2.0 was correlated with primary tumor size (p<0.001), SUV_tumor (p<0.001), MTV_tumor (p<0.001), TLG_tumor (p<0.001), depth of cervical invasion (p<0.001), and negatively correlated with age (p=0.036). Tumor recurrence was significantly associated with TLG_tumor (p<0.001), MTV_tumor (p=0.001), SUV_LN (p=0.004), IFH (p=0.005), SUV_tumor (p=0.015), and FIGO stage (p=0.015). Multivariate analysis identified that IFH (p=0.028; hazard ratio, 756.997; 95% CI, 2.047 to 279,923.191) was the only independent risk factor for recurrence. The Kaplan-Meier survival graphs showed that PFS significantly differed in groups categorized based on IFH (p=0.013, log-rank test).

Conclusion

Preoperative IFH was significantly associated with cervical cancer recurrence. [¹⁸F]FDG based heterogeneity may be a useful and potential predicator of patient recurrence before treatment.     

Analysis of positron emission tomography/computed tomography in patients to differentiate between malignant transformation of endometrioma and endometrioma

Purpose

Of those patients who undergo open surgery for a suspicion of malignant transformation of endometrioma (MTOE) due to solid nodule enhancement identified by contrast-enhanced magnetic resonance imaging (MRI), some benign endometrioma cases are included. The aim of this retrospective study was to determine the value and diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) using 18-fluoro-2-deoxy-d-glucose (FDG) to differentiate between MTOE and endometrioma.

Patients and methods

We retrospectively analyzed 1599 consecutive patients who underwent laparoscopic surgery for the diagnosis of endometrioma preoperatively and 31 patients who underwent open surgery for a suspicion of MTOE preoperatively from January 2003 to December 2011. We analyzed the age, serum CA125 levels, and MRI findings of the patients and calculated the optimal cut-off value for PET/CT using receiver operating characteristic curve analysis.

Results

Of the 1,599 patients who underwent laparoscopic surgery for a suspicion of endometrioma preoperatively, malignancy was identified in one (0.062 %) patient. Of the 31 patients who underwent open surgery for a suspicion of MTOE preoperatively, 11 were diagnosed with endometrioma (false positive group) and 20 with MTOE stage I (positive group). Age, tumor size, presence of shading on MRI and maximum standardized uptake values (SUV_max) on PET/CT were significantly different between the two groups. A SUV_max cut-off >4.0 is capable of excluding endometrioma cases, with 75 % sensitivity and 100 % specificity (area under the curve 90 %).

Conclusion

PET/CT is a good diagnostic tool for MTOE using the optimal SUV_max cut-off of 4.0 (75 % sensitivity and 100 % specificity).

     

Preoperative [18F]FDG PET/CT predicts recurrence in patients with epithelial ovarian cancer

Objective

To determine whether [¹⁸F]FDG uptake on PET/CT imaging before surgical staging has prognostic significance in patients with epithelial ovarian cancer (EOC).

Methods

Patients with EOC were imaged with integrated PET/CT before surgical staging. Hypermetabolic lesions were measured as the standardized uptake value (SUV) in primary and metastatic tumors. SUV distribution was divided into two regions at the level of umbilicus, and the impact of the ratio between above and below umbilicus (SUV_location ratio) on progression-free survival (PFS) was examined using Cox proportional hazards regression.

Results

Between January 2004 and December 2009, 55 patients with EOC underwent preoperative PET/CT. The median duration of PFS was 11 months (range, 3 to 43 months), and twenty (36.4%) patients experienced recurrence. In univariate analysis, high SUV_location ratio (p=0.002; hazard ratio [HR], 1.974; 95% confidence interval [CI], 1.286 to 3.031) was significantly associated with recurrence. Malignant mixed mullerian tumor compared with endometrioid histology was also shown to have significance. In multivariate analysis, high SUV_location ratio (p=0.005; HR, 2.418; 95% CI, 1.1315 to 4.447) and histology (serous, mucinous, and malignant mixed mullerian tumor compared with endometrioid type) were significantly associated with recurrence. Patients were categorized into two groups according to SUV_location ratio (<0.3934 vs. ≥0.3934), and the Kaplan-Meier survival graph showed a significant difference in PFS between the groups (p=0.0021; HR, 9.47, log-rank test).

Conclusion

SUV distribution showed a significant association with recurrence in patients with EOC, and may be a useful predictor of recurrence.     

Is F-FDG PET useful in predicting the WHO grade of malignancy in thymic epithelial tumors? A meta-analysis

Aim

To perform a systematic review and meta-analysis of published data on the role of fluorine-18-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in predicting the WHO grade of malignancy in thymic epithelial tumors (TETs).

Methods

A comprehensive literature search of studies published up to March 2014 was performed. Data on maximum standardized uptake value (SUV_max) in patients with low-risk thymomas (A, AB, B1), high-risk thymomas (B2, B3) and thymic carcinomas (C) according to the WHO classification were collected when reported by the retrieved articles. The comparison of mean SUV_max between low-risk thymomas, high-risk thymomas and thymic carcinomas was expressed as weighted mean difference (WMD) and a pooled WMD was calculated including 95% confidence interval (95%CI).

Results

Eleven studies were selected for the meta-analysis. The pooled WMD of SUV_max between high-risk and low-risk thymomas was 1.2 (95%CI: 0.4–2.0). The pooled WMD of SUV_max between thymic carcinomas and low-risk thymomas was 4.8 (95%CI: 3.4–6.1). Finally, the pooled WMD of SUV_max between thymic carcinomas and high-risk thymomas was 3.5 (95%CI: 2.7–4.3).

Conclusions

¹⁸F-FDG PET may predict the WHO grade of malignancy in TETs. In particular, we demonstrated a statistically significant difference of SUV_max between the different TETs (low-grade thymomas, high-grade thymomas and thymic carcinomas).     

PET imaging of patients with non-small cell lung cancer employing an EGF receptor targeting drug as tracer

Background:

We have previously developed ¹¹C-erlotinib as a new positron emission tomography (PET) tracer and shown that it accumulates in epidermal growth factor receptor (EGFR)-positive lung cancer xenografts in mice. Here, we present a study in patients with non-small cell lung cancer (NSCLC) investigating the feasibility of ¹¹C-erlotinib PET as a potential method for the identification of lung tumours accumulating erlotinib.

Methods:

Thirteen patients with NSCLC destined for erlotinib treatment were examined by contrast-enhanced computed tomography (CT), ¹¹C-erlotinib PET/low-dose CT and ¹⁸F-fluoro-2-deoxy--glucose (¹⁸F-FDG) PET/low-dose CT before start of the erlotinib treatment. After 12 weeks treatment, they were examined by ¹⁸F-FDG PET/contrast-enhanced CT for the assessment of clinical response.

Results:

Of the 13 patients included, 4 accumulated ¹¹C-erlotinib in one or more of their lung tumours or lymph-node metastases. Moreover, ¹¹C-erlotinib PET/CT identified lesions that were not visible on ¹⁸F-FDG PET/CT. Of the four patients with accumulation of ¹¹C-erlotinib, one died before follow-up, whereas the other three showed a positive response to erlotinib treatment. Three of the nine patients with no accumulation died before follow-up, four showed progressive disease while two had stable disease after 12 weeks of treatment.

Conclusion:

Our data show a potential for ¹¹C-erlotinib PET/CT for visualizing NSCLC lung tumours, including lymph nodes not identified by ¹⁸F-FDG PET/CT. Large clinical studies are now needed to explore to which extent pre-treatment ¹¹C-erlotinib PET/CT can predict erlotinib treatment response.     

Use of 18F-FDG PET/CT to locate primary malignancies in patients with hepatic cirrhosis and malignant ascites

Objective：Ascites in patients with hepatic cirrhosis is caused by cirrhosis in most cases.For most malignant ascites,the primary malignancy could be readily identified using conventional imaging methods,e.g.,computer tomography （CT） and magnetic resonance imaging （MRI）.However,in a small fraction of the patients,the primary malignancy remains occult even with these examinations.In this retrospective study,we assessed the usefulness of 18F-FDG PET/CT in patients with hepatic cirrhosis and malignant ascites of otherwise unknown origin.Methods：Twenty-eight patients with malignant ascites of unknown primary sites after CT,MRI and ultrasound during the period of five years between January 2008 and December 2012 had received 18F-FDG PET/CT.Medical records of these patients were reviewed and analyzed.Results：Elevated 18F-FDG absorption was found in 23 of 28 cases in the following sites：gastrointestinal tract （n=10,43.5％）,prostate （n=5,21.7％）,peritoneum （n=4,13.3％）,and ovary （n=4,13.3％）.Cancer was confirmed by pathology in 20 cases after open or laparoscopic surgeries.Five patients were found to have benign ascites,among which,3 were found to be false positive due to tuberculosis.SUV values were significantly higher for tumors than for benign lesions （mean values,6.95 vs.2.94; P=0.005）.Conclusions：The 18F-FDG PET/CT can be as a powerful imaging tool in identifying tissue origin in liver cirrhosis patients suspected of cancers or with cancers of unknown primary sites.