Prediction of response to neoadjuvant chemotherapy by sequential F-18-fluorodeoxyglucose positron emission tomography in patients with advanced-stage ovarian cancer

Evaluation of metabolic response with 18F-FDG PET-CT in patients with advanced or recurrent thymic epithelial tumors

BACKGROUND

Patients with advanced or recurrent thymic epithelial tumors (TETs) often need several consecutive lines of chemotherapy. The aim of this retrospective monocentric study was to test whether ¹⁸F-Fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET-CT) is able to monitor standard chemotherapy efficacy in those patients and whether metabolic response correlates with morphovolumetric response as assessed by Response Evaluation Criteria in Solid Tumor (RECIST).

METHODS

We evaluated 27 consecutive patients with advanced (16 patients) or recurrent (11 patients) TETs. All patients underwent ¹⁸F-FDG PET-CT before and after at least 3 cycles of chemotherapy. Maximum standardized uptake value (SUV_max) of all detected lesions was recorded and the most ¹⁸F-FDG avid lesion in each patient was selected for determination of percentage change of SUV_max (ΔSUV_max) in pre- and post-treatment scans. Tumor response was assessed by contrast-enhanced computed tomography (CE-CT) using RECIST criteria. Receiver operating characteristic (ROC) curve analysis was performed to define the optimal threshold of ΔSUV_max discriminating responders from non-responders.

RESULTS

Metabolic response expressed as ΔSUV_max was significantly correlated with morphovolumetric response (Spearman's rank correlation, r = 0.64, p = 0.001). ROC curve analysis showed that a ΔSUV_max value of -25% could discriminate responders from non-responders with a sensitivity of 88% and a specificity of 80%. Conversely, basal SUV_max values were not predictive of morphovolumetric tumor response.

CONCLUSIONS

Our findings indicate that metabolic response assessed by ¹⁸F-FDG PET-CT, through evaluation of ΔSUV_max, may allow identification of responders and non-responders thus guiding adaptation of therapy in patients with advanced or recurrent TETs.

Repeatability of SUV in Oncologic 18F-FDG PET

Quantitative analysis can potentially improve the accuracy and consistency of ¹⁸F-FDG PET, particularly for the assessment of tumor response to treatment. Although not without limitations, SUV has emerged as the predominant metric for tumor quantification with ¹⁸F-FDG PET. Growing literature suggests that the difference between SUVs measured before and after treatment can be used to predict tumor response at an early stage. SUV is, however, associated with multiple sources of variability, and to best use SUV for response assessment, an understanding of the repeatability of the technique is required. Test-retest studies involve repeated scanning of the same patient on the same scanner using the same protocol no more than a few days apart and provide basic information on the repeatability of the technique. Multiple test-retest studies have been performed to assess SUV repeatability, although a comparison of reports is complicated by the use of different methodologies and statistical metrics. This article reviews the available data, addressing issues such as different repeatability metrics, relative units, log transformation, and asymmetric limits of repeatability. When acquired with careful attention to protocol, tumor SUV has a within-subject coefficient of variation of approximately 10%. In a response assessment setting, SUV reductions of more than 25% and increases of more than 33% are unlikely to be due to measurement variability. Broader margins may be required for sites with less rigorous protocol compliance, but in general, SUV is a highly repeatable imaging biomarker that is ideally suited to monitoring tumor response to treatment in individual patients.

An update on the role of PET/CT and PET/MRI in ovarian cancer

This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as ¹⁸F-fluorothymidine (FLT) or ¹¹C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer.

Insulin-Like Growth Factors and Their Binding Proteins in Tumors and Ascites of Ovarian Cancer Patients: Association With Response To Neoadjuvant Chemotherapy

Purpose: Tumor cell growth and sensitivity to chemotherapy depend on many factors, among which insulin-like growth factors (IGFs) may play important roles. The aim of the present study was to evaluate the levels of insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) in primary tumors and ascites as predictors of response to neoadjuvant chemotherapy in ovarian cancer (OC) patients. Materials and Methods: Tumor tissue samples and ascitic fluid were obtained from 59 patients with advanced OC. The levels of IGF-I, IGF-II, IGFBP-3, IGFBP-4 and PAPP-A were determined using ELISA kits. Taking into account the data on expression of these IGF-related proteins and outcome, logistic regression was performed to identify predictors of response to neoajuvant chemotherapy. Results: Human ovarian tumors expressed IGFs, IGFBP-3, IGFBP-4 and PAPP-A and these proteins were also present in ascites fluid and associated with its volume. IGFs and IGFBPs in ascites and soluble PAPP-A might play a key role in ovarian cancer progression . However, levels of proteins of the IGF system in tumors were not significant predictors of objective clinical response (oCR). Univariate analysis showed that the level of IGF-I in ascites was the only independent predictor for oCR. Conclusion: The level of IGF-I in ascites was shown to be an independent predictor of objective clinical response to chemotherapy for OC patients treated with neoadjuvant chemotherapy and debulking surgery.

Effectiveness of FDG-PET/CT for evaluating early response to induction chemotherapy in head and neck squamous cell carcinoma: A systematic review

BACKGROUND

F-Fluoro-Deoxy-Glucose Positron Emission Tomography with Computed Tomography (F-FDG PET/CT) may be a powerful tool to predict treatment outcome. We aimed to review the effectiveness of F-FDG PET/CT in the assessment of early response to induction chemotherapy (IC) in patients with advanced Head and Neck Squamous Cell Cancer (HNSCC) without previous treatment.

METHODS

PubMed, Cochrane Library, Science Direct and Web of Science were searched to May 2016. Reference lists of the included articles and additional studies identified by one nuclear medicine expert were screened for potential relevant studies that investigated the effectiveness of F-FDG PET/CT performed before and after IC. Three authors independently screened all retrieved articles, selected studies that met inclusion criteria and extracted data. The methodology of the selected studies was evaluated by using the risk of bias checklist of the Agency for Healthcare Research and Quality (AHRQ).

RESULTS

Seven out of 170 eligible studies met our inclusion criteria. A total of 207 advanced HNSCC patients were evaluated with F-FDG PET/CT at baseline and after IC in the selected articles. Six from seven studies concluded that F-FDG PET/CT allowed early evaluation response to IC and predicted survival outcomes.

CONCLUSION

The present systematic review confirms the potential value of F-FDG PET/CT as a diagnostic tool for early IV response assessment in HNSCC patients. However, the lack of standard definitions for response criteria and heterogeneous IC protocols indicate the need to further studies in order to better define the role of F-FDG PET/CT in these patients.

Altered glutamine metabolism in platinum resistant ovarian cancer

Ovarian cancer is characterized by an increase in cellular energy metabolism, which is predominantly satisfied by glucose and glutamine. Targeting metabolic pathways is an attractive approach to enhance the therapeutic effectiveness and to potentially overcome drug resistance in ovarian cancer. In platinum-sensitive ovarian cancer cell lines the metabolism of both, glucose and glutamine was initially up-regulated in response to platinum treatment. In contrast, platinum-resistant cells revealed a significant dependency on the presence of glutamine, with an upregulated expression of glutamine transporter ASCT2 and glutaminase. This resulted in a higher oxygen consumption rate compared to platinum-sensitive cell lines reflecting the increased dependency of glutamine utilization through the tricarboxylic acid cycle. The important role of glutamine metabolism was confirmed by stable overexpression of glutaminase, which conferred platinum resistance. Conversely, shRNA knockdown of glutaminase in platinum resistant cells resulted in re-sensitization to platinum treatment. Importantly, combining the glutaminase inhibitor BPTES with platinum synergistically inhibited platinum sensitive and resistant ovarian cancers in vitro. Apoptotic induction was significantly increased using platinum together with BPTES compared to either treatment alone. Our findings suggest that targeting glutamine metabolism together with platinum based chemotherapy offers a potential treatment strategy particularly in drug resistant ovarian cancer.

Assessment of Therapy Response by FDG PET in Infection and Inflammation

Positron emission tomography (PET) is a well-known imaging modality in assessing the treatment response to chemotherapy or radiotherapy in various malignancies. A systematic review of the literature reveals a few publications reporting evaluation of the treatment response in benign conditions using PET/computed tomography. PET holds a promising future role in the follow-up of inflammatory or infectious diseases. In this article, [(18)F]Fluorodeoxyglucose PET as a tool in the evaluation, treatment, and follow-up of infectious and inflammatory diseases is discussed.

Interobserver and Intraobserver Variability among Measurements of FDG PET/CT Parameters in Pulmonary Tumors

BACKGROUND

18F-fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET/CT) provides information about metabolic and morphologic status of malignancies. Tumor size and standardized uptake value (SUV) measurements are crucial for cancer treatment monitoring.

AIMS

The purpose of our study was to assess the variability of these measurements performed by observers evaluating lung tumors.

STUDY DESIGN

Retrospective cross-sectional study.

METHODS

FDG PET/CT images of 97 patients with pulmonary tumors were independently evaluated by two experienced nuclear medicine physicians. Primary tumor size (UDCT), maximum SUV (SUVmax), mean SUV (SUVmean) and maximum SUV normalized to liver mean SUV (SUVnliv max) were measured by each observer at two different times with an interval of at least 2 weeks. Interobserver and intraobserver variabilities of measurements were evaluated through statistical methods.

RESULTS

Size of the lesions varied from 0.81 to 13.6 cm (mean 4.29±2.24 cm). Very good agreement was shown with correlation, Bland-Altman and regression analysis for all measured PET/CT parameters. In the interobserver and intraobserver variability analysis, the Pearson correlation coefficients were greater than 0.96 and 0.98, respectively.

CONCLUSION

Semi-quantitative measurements of pulmonary tumors were highly reproducible when determined by experienced physicians with clinically available software for routine FDG PET/CT evaluation. Consistency may be improved if the same observer performs serial measurements for any one patient.

Accumulation of ALDH1-positive cells after neoadjuvant chemotherapy predicts treatment resistance and prognosticates poor outcome in ovarian cancer

Although ovarian cancer is a highly chemosensitive disease, it is only infrequently cured. One of the major reasons lies in the presence of drug-resistant cancer stem-like cells, sufficient to fuel recurrence. We phenotyped cancer stem-like cells by flow cytometry and immunohistochemistry in 55 matched samples before and after taxane/platinum-based neoadjuvant chemotherapy. All used markers of stemness (ALDH1, CD24, CD117, CD133) isolated low frequencies of malignant cells. ALDH1 was the most valuable marker for tracking stemness in vivo. The enrichment of ALDH1 expression after treatment was associated with a poor response to chemotherapy, with platinum resistance and independently prognosticated unfavorable outcome. Our results suggest that increased ALDH1 expression after treatment identifies patients with aggressive tumor phenotypes.

Nuclear medicine for imaging of epithelial ovarian cancer

Cancer is one of the leading causes of mortality worldwide. Usually, the diagnosis of cancer at an early stage is important to facilitate proper treatment and survival. Nuclear medicine has been successfully used in the diagnosis, staging, therapy and monitoring of cancers. Single-photon emission computed tomography and PET-based companion imaging agents are in development for use as a companion diagnostic tool for patients with ovarian cancer. The present review discusses the basic and clinical studies related to the use of radiopharmaceuticals in the diagnosis and management of ovarian cancer, focusing on their utility and comparing them with other imaging techniques such as computed tomography and MRI.

Functional MR Imaging in Gynecologic Cancer

Dynamic-contrast enhanced (DCE) and diffusion-weighted (DW) MR imaging are invaluable in the detection, staging, and characterization of uterine and ovarian malignancies, for monitoring treatment response, and for identifying disease recurrence. When used as adjuncts to morphologic T2-weighted (T2-W) MR imaging, these techniques improve accuracy of disease detection and staging. DW-MR imaging is preferred because of its ease of implementation and lack of need for an extrinsic contrast agent. MR spectroscopy is difficult to implement in the clinical workflow and lacks both sensitivity and specificity. If used quantitatively in multicenter clinical trials, standardization of DCE- and DW-MR imaging techniques and rigorous quality assurance is mandatory.

Multicenter Reproducibility of 18F-Fluciclatide PET Imaging in Subjects with Solid Tumors

Integrins are upregulated on both tumor cells and associated vasculature, where they play an important role in angiogenesis and metastasis. Fluciclatide is an arginine-glycine-aspartic acid peptide with high affinity for αvβ3/αvβ5 integrin, which can be radiolabeled for PET imaging of angiogenesis. Thus, (18)F-fluciclatide is a potential biomarker of therapeutic response to antiangiogenic inhibitors. The aim of this study was to evaluate the reproducibility of (18)F-fluciclatide in multiple solid-tumor types.

METHODS

Thirty-nine patients underwent PET/CT scanning at 40, 65, and 90 min after injection of (18)F-fluciclatide (maximum, 370 MBq) on 2 separate days (2-9 d apart). Patients did not receive any therapy between PET/CT scans. (18)F-fluciclatide images were reported and quantitative measures of uptake were extracted using the PERCIST methodology. Intrasubject reproducibility of PET uptake in all measurable lesions was evaluated by calculating relative differences in SUV between PET scans for each lesion during the 2 imaging sessions.

RESULTS

Thirty-nine measurable lesions were detected in 26 patients. Lesion uptake correlated strongly across imaging sessions (r = 0.92, P < 0.05, at 40 min; r = 0.94, P < 0.05, at 65 min; r = 0.94, P < 0.05, at 90 min) with a mean relative difference and SD of the relative difference of 0.006 ± 0.18 at 40 min, 0.003 ± 0.19 at 65 min, and 0.025 ± 0.20 at 90 min. This reflects 95% limits of repeatability of 35%-39% for the difference between the 2 SUV measurements or a variability of 18%-20% in agreement from that observed in well-calibrated multicenter (18)F-FDG studies.

CONCLUSION

The test-retest reproducibility of (18)F-fluciclatide across multiple tumor types has been measured and shown to be acceptable. This is an important step in the development of this in vivo biomarker to identify and quantify response to antiangiogenic therapy in cancer patients.

Prognostic value of (18)F-FDG PET/CT volumetric parameters in recurrent epithelial ovarian cancer

OBJECTIVE

Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) from (18)F-FDG PET/CT are emerging prognostic biomarkers in various solid neoplasms. These volumetric parameters and the SUVmax have shown to be useful criteria for disease prognostication in preoperative and post-treatment epithelial ovarian cancer (EOC) patients. The purpose of this study was to evaluate the utility of (18)F-FDG PET/CT measurements to predict survival in patients with recurrent EOC.

MATERIAL AND METHODS

Twenty-six patients with EOC who underwent a total of 31 (18)F-FDG PET/CT studies for suspected recurrence were retrospectively included. SUVmax and volumetric parameters whole-body MTV (wbMTV) and whole-body TLG (wbTLG) with a threshold of 40% and 50% of the SUVmax were obtained. Correlation between PET parameters and progression-free survival (PFS) and the survival analysis of prognostic factors were calculated.

RESULTS

Serous cancer was the most common histological subtype (76.9%). The median PFS was 12.5 months (range 10.7-20.6 months). Volumetric parameters showed moderate inverse correlation with PFS but there was no significant correlation in the case of SUVmax. The correlation was stronger for first recurrences. By Kaplan-Meier analysis and log-rank test, wbMTV 40%, wbMTV 50% and wbTLG 50% correlated with PFS. However, SUVmax and wbTLG 40% were not statistically significant predictors for PFS.

CONCLUSION

Volumetric parameters wbMTV and wbTLG 50% measured by (18)F-FDG PET/CT appear to be useful prognostic predictors of outcome and may provide valuable information to individualize treatment strategies in patients with recurrent EOC.

18F-FDG-PET/CT can identify histopathological non-responders to platinum-based neoadjuvant chemotherapy in advanced epithelial ovarian cancer

OBJECTIVE

The aim of this study was to examine the relationship between the reduction of maximum standardized uptake values (SUVmax) in 18F-FDG-PET/CT to histopathological changes obtained with neoadjuvant chemotherapy (NACT) in advanced epithelial ovarian cancer (EOC). We wanted to evaluate whether 18F-FDG-PET/CT is useful for identifying patients who will not respond to NACT and would therefore benefit from second-line chemotherapy instead of interval debulking surgery (IDS).

METHODS

Twenty-six primarily inoperable EOC patients treated with NACT were enrolled in this study. 18F-FDG-PET/CT imaging was performed before diagnostic laparoscopy and after three to four NACT cycles. The relationship between the decrease in omental SUVmax from before to after NACT with omental histopathological response was examined in samples taken from the corresponding anatomical sites during IDS. Patients were divided into three groups according to chemotherapy-induced histopathological changes. Serum CA125 and HE4 halftimes during NACT as well as Ki-67 antigen expression in IDS samples were determined.

RESULTS

The median omental SUVmax change during NACT was -64% (range-16% to -84%), and it was associated with histopathological response (p=0.004, OR 0.9, CI 0.84-0.97). A SUVmax decrease of less than 57% identified histopathological non-responders. Progression-free survival (PFS) differed between the poor, moderate and good histopathological response groups (0.9 year vs. 1.2 years vs. 1.4 years, respectively, p=0.05). The SUVmax change was not associated with PFS.

CONCLUSION

18F-FDG-PET/CT was able to identify patients who would not respond to NACT. To obtain a histopathological response in EOC, a substantial metabolic response in 18F-FDG-PET/CT is necessary.

Diagnostic and prognostic evaluation of fluorodeoxyglucose positron emission tomography/computed tomography and its correlation with serum cancer antigen-125 (CA125) in a large cohort of ovarian cancer patients

OBJECTIVE

We evaluated the efficacy of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in recurrent disease, response to therapy, and long-term follow-up of ovarian cancer (OC) patients in relation to cancer antigen-125 (CA125) levels and the prognostic meaning of this modality in this subset of subjects.

MATERIAL AND METHODS

Between 2005 and 2015, we retrospectively evaluated 125 patients affected by OC who underwent FDG PET/CT imaging at our institution. The indications for PET/CT were recurrence of disease in 78 patients, therapy response assessment in 29, and follow-up in 18. The results of FDG PET/CT were compared with those of histopathology and clinical and radiological progression during follow-up for at least 6 months. The median long-term follow-up was 33 months. The diagnostic accuracies for the different clinical settings were evaluated. The relationships among global survival (GS), FDG PET/CT results, and CA125 levels were evaluated by both Kaplan-Meier and Cox regression analysis.

RESULTS

CA125 results were positive (>35 UI/mL) in 62 patients and negative in 63 (49% vs. 51%). The sensitivity and specificity of CA125 were 72% and 91%, respectively. PET/CT imaging showed a sensitivity of 98.6% and a specificity of 77.8% for the assessment of recurrent disease, and a sensitivity of 72.7% and a specificity of 88.9% for therapy evaluation. Meanwhile, in 18 patients evaluated during follow-up, the specificity was 82.3%. GS was significantly higher in case of negative CA125 values at the time of FDG PET/CT, of a negative PET/CT scan and when no evidence of peritoneum recurrence and distant metastases was determined by PET. Multivariate regression analysis showed that only age and peritoneum recurrence as determined by PET were identified as independent predictors of poor prognosis.

CONCLUSION

Metabolic imaging with FDG PET/CT proved useful in patients where OC recurrence was suspected, even when the value of tumor marker CA125 was in a normal range. A positive PET/CT scan and the presence of peritoneum recurrence at PET were associated with a poor prognosis after approximately 30 months.

Gynecologic oncologic imaging with PET/CT

FDG-PET/CT has been evaluated in a variety of gynecologic malignancies in a variety of settings and is approved by the Centers for Medicare & Medicaid Services for the initial and subsequent treatment strategies of these malignancies. Cervical cancer is typically very FDG avid, and FDG-PET/CT appears to be most valuable for initial staging, radiation therapy planning, and detection of recurrent disease. For ovarian cancer, the most value of FDG-PET/CT appears to be for detecting recurrent disease in the setting of rising CA-125 level and negative or equivocal anatomical imaging studies. Initial studies evaluating response to therapy are promising and further work in this area is needed. FDG uptake in both nonmalignant and physiological processes in the pelvis can make interpretation of FDG-PET/CT in this region challenging and knowledge of these entities and patterns can avoid misinterpretation. Some of the most common findings relate to the cyclic changes that occur as part of the menstrual cycle in premenopausal women. Mucinous tumors and low-volume or peritoneal carcinomatosis are causes of false-negative results on FDG-PET/CT studies. As new tracers are developed, comparisons with patient outcomes and standards of care (eg, FDG-PET/CT) will be needed.

A Systematic Comparison of 18F-C-SNAT to Established Radiotracer Imaging Agents for the Detection of Tumor Response to Treatment

PURPOSE

An early readout of tumor response to therapy through measurement of drug or radiation-induced cell death may provide important prognostic indications and improved patient management. It has been shown that the uptake of (18)F-C-SNAT can be used to detect early response to therapy in tumors by positron emission tomography (PET) via a mechanism of caspase-3-triggered nanoaggregation.

EXPERIMENTAL DESIGN

Here, we compared the preclinical utility of (18)F-C-SNAT for the detection of drug-induced cell death to clinically evaluated radiotracers, (18)F-FDG, (99m)Tc-Annexin V, and (18)F-ML-10 in tumor cells in culture, and in tumor-bearing mice in vivo.

RESULTS

In drug-treated lymphoma cells, (18)F-FDG, (99m)Tc-Annexin V, and (18)F-C-SNAT cell-associated radioactivity correlated well to levels of cell death (R(2) > 0.8; P < 0.001), with no correlation measured for (18)F-ML-10 (R(2) = 0.05; P > 0.05). A similar pattern of response was observed in two human NSCLC cell lines following carboplatin treatment. EL-4 tumor uptake of (99m)Tc-Annexin V and (18)F-C-SNAT were increased 1.4- and 2.1-fold, respectively, in drug-treated versus naïve control animals (P < 0.05), although (99m)Tc-Annexin V binding did not correlate to ex vivo TUNEL staining of tissue sections. A differential response was not observed with either (18)F-FDG or (18)F-ML-10.

CONCLUSIONS

We have demonstrated here that (18)F-C-SNAT can sensitively detect drug-induced cell death in murine lymphoma and human NSCLC. Despite favorable image contrast obtained with (18)F-C-SNAT, the development of next-generation derivatives, using the same novel and promising uptake mechanism, but displaying improved biodistribution profiles, are warranted for maximum clinical utility.

Neoadjuvant chemotherapy in gynaecological cancers - Implications for staging

The management of advanced gynaecological cancers remains a therapeutic challenge. Neoadjuvant chemotherapy has been used to reduce tumour size, thus facilitating subsequent local treatment in the form of surgery or radiation. For advanced epithelial ovarian cancer, data from several non-randomized and one randomized studies indicate that neoadjuvant chemotherapy followed by interval debulking surgery is a reasonable approach in patients deemed inoperable. Such an approach results in optimum debulking (no visible tumour) in approximately 40% of the patients with reduced operative morbidity. Overall and progression free-survival is comparable to the group treated with primary debulking surgery followed by chemotherapy. Neoadjuvant chemotherapy followed by surgery is associated with improved survival for women with stage IB2-IIA cervix cancer. There is a resurgence of interest for using short-course neoadjuvant chemotherapy prior to concurrent chemo-radiation. Currently, this is being tested in randomized trials.

Predicting outcome in patients with rhabdomyosarcoma: role of [(18)f]fluorodeoxyglucose positron emission tomography

PURPOSE

To evaluate whether [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) response of the primary tumor after induction chemotherapy predicts outcomes in rhabdomyosarcoma (RMS).

METHODS AND MATERIALS

After excluding those with initial tumor resection, 107 patients who underwent FDG-PET after induction chemotherapy at Memorial Sloan Kettering Cancer Center from 2002 to 2013 were reviewed. Local control (LC), progression-free survival (PFS), and overall survival (OS) were calculated according to FDG-PET response and maximum standardized uptake value (SUV) at baseline (PET1/SUV1), after induction chemotherapy (PET2/SUV2), and after local therapy (PET3/SUV3). Receiver operator characteristic curves were used to determine the optimal cutoff for dichotomization of SUV1 and SUV2 values.

RESULTS

The SUV1 (<9.5 vs ≥9.5) was predictive of PFS (P=.02) and OS (P=.02), but not LC. After 12 weeks (median) of induction chemotherapy, 45 patients had negative PET2 scans and 62 had positive scans: 3-year PFS was 72% versus 44%, respectively (P=.01). The SUV2 (<1.5 vs ≥1.5) was similarly predictive of PFS (P=.005) and was associated with LC (P=.02) and OS (P=.03). A positive PET3 scan was predictive of worse PFS (P=.0009), LC (P=.05), and OS (P=.03).

CONCLUSIONS

[(18)F]fluorodeoxyglucose positron emission tomography is an early indicator of outcomes in patients with RMS. Future prospective trials may incorporate FDG-PET response data for risk-adapted therapy and early assessment of new treatment regimens.

Does early PET/CT assesment of response to chemotherapy predicts survival in patients with advanced stage non-small-cell lung cancer?

The aim of this study is to determine the prognostic role and the timing of metabolic response to chemotherapy, based on F-fluorodeoxyglucose positron emission tomography (F-FDG-PET), in patients with metastatic non-small-cell lung cancer (NSCLC). The study included 55 patients with metastatic NSCLC that were analyzed in terms of prognostic factors and survival. F-FDG-PET/CT findings were evaluated in patients separated into 3 groups, before and after 1st, 2nd, 3rd cycle of the first line chemotherapy. Metabolic response was assessed according to PET Response Criteria in Solid Tumors (PERCIST 1.0). Among the 55 patients, 34 (62%) died, and 21 (38%) remained alive during a mean follow-up of 13.5 months. Median overall survival (OS) was 11.69 months (range 2-26.80 months) and median progression-free survival (PFS) was 6.27 months (range 1.37-20.43 months). Univariate analysis showed that the only favorable prognostic factor for OS in all the patients was the achievement of metabolic response. Metabolic response according to PERCIST, and weight lose ≤ 5% were also independent favorable prognostic factors predictive of survival in all patients based on multivariet analysis (metabolic response: P=0.002, OR; 1.90, 95% CI 1.26-2.89, and weight lose ≤5%: P=0.022, OR; 2.24, 95% CI 1.12-4.47). Median OS in all patients with partial response (PR)-according to the PERCIST 1.0- was significantly longer than in those with progressive disease (PD) (16.36 months vs 8.14 months, P=0.008). Median OS in the patients with PR was significantly longer than in those with PD based on PET/CT performed after 2nd and 3rd cycles of chemotherapy (18.35 months vs 7.54 months, P=0.012 and 18.04 months vs 7.43 months, P<0.001, respectively), whereas, median OS did not differ significantly between patients with PR and those with PD based on PET/CT performed after the 1st cycle of chemotherapy (8.01 months vs 5.08 months, P=0.290). Metabolic response according to PERCIST and weight loss are independent factors predictive of OS. PET/CT performed after second cycle of chemotherapy may be the earliest predictor of treatment response in patients with advanced stage NSCLC.

Role of 18F-FDG PET/CT in the carcinoma of the uterus: a review of literature

In the present review we reported the value of 18F-fluorodeoxyglucose (FDG) PET/CT in face of uterine cancer, in terms of sensitivity, specificity and accuracy. Moreover, we made a comparison with the other imaging techniques currently used to evacuate these tumors including contrast-enhanced CT, contrast enhanced-MRI and transvaginal ultrasonography. FDG PET/CT has been reported to be of particular value in detecting occult metastatic lesions, in prediction of response to treatment and as a prognostic factor.

Monitoring of tumor response to cisplatin with simultaneous fluorescence and positron emission tomography: a feasibility study

Dual modality molecular imaging can capture concurrent molecular events and evaluate therapeutic efficacy from uniquely different perspectives based on different molecular targets. In this work, dual modality tomographic imaging, (18) F-fluorodeoxyglucose based positron emission tomography and subsurface fluorescence molecular tomography ([(18) F]FDG-PET/subsurface FMT), is proposed to monitor tumor response to cisplatin on a mouse xenograft model in vivo. One mouse was administered with cisplatin (1.0 mg/kg) by intraperitoneal injection once every day for 14 days, and another mouse was administered with saline to serve as the control. Dual modality [(18) F]FDG-PET/subsurface FMT imaging was conducted on days 0, 2, 5, 9, 15, and 22. In vivo imaging and quantitative analysis demonstrated the feasibility of [(18) F]FDG-PET/subsurface FMT imaging in tracking the changes of [(18) F]FDG tumor uptake and amount of red fluorescent protein (RFP) synthesized by tumor cells in the same mouse simultaneously. Dual modality [(18) F]FDG-PET/subsurface FMT imaging may thus provide a powerful tool for better understanding disease progress and treatment evaluation from different perspectives.

Correlation between ovarian neoplasm and serum levels of osteopontin: a meta-analysis

The aim of this meta-analysis was to evaluate the clinical significance of serum osteopontin (OPN) levels in ovarian neoplasm in patients, with the goal of building a novel diagnostic score model. By searching the PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, CBM, and China National Knowledge Infrastructure (CNKI) databases, we conducted a meta-analysis. Studies were pooled, and the standardized mean difference (SMD) and its corresponding 95 % confidence interval (CI) were calculated. Subgroup analyses and publication bias detection were also conducted. Version 12.0 STATA software was used for statistical analysis. We performed a final analysis of 1,653 subjects altogether (822 patients with psoriasis and 831 healthy controls) from 15 clinical case-control studies. The meta-analysis results showed a positive association between serum OPN levels and ovarian neoplasm (SMD = 2.60, 95 %CI 1.88-3.32, P < 0.001). The subgroup analysis by ethnicity detected that high levels of serum OPN may be the main risk factor for ovarian neoplasms in Asians (SMD = 2.91, 95 %CI 2.38-3.45, P < 0.001), but not in Caucasians (P > 0.05). The present meta-analysis indicated that serum OPN levels were generally elevated in ovarian neoplasm patients, and thus, serum levels of OPN could be useful in diagnosing ovarian neoplasm.

Repeatability of quantitative FDG-PET/CT and contrast-enhanced CT in recurrent ovarian carcinoma: test-retest measurements for tumor FDG uptake, diameter, and volume

PURPOSE

Repeatability of baseline FDG-PET/CT measurements has not been tested in ovarian cancer. This dual-center, prospective study assessed variation in tumor 2[18F]fluoro-2-deoxy-D-glucose (FDG) uptake, tumor diameter, and tumor volume from sequential FDG-PET/CT and contrast-enhanced computed tomography (CECT) in patients with recurrent platinum-sensitive ovarian cancer.

EXPERIMENTAL DESIGN

Patients underwent two pretreatment baseline FDG-PET/CT (n = 21) and CECT (n = 20) at two clinical sites with different PET/CT instruments. Patients were included if they had at least one target lesion in the abdomen with a standardized uptake value (SUV) maximum (SUVmax) of ≥ 2.5 and a long axis diameter of ≥ 15 mm. Two independent reading methods were used to evaluate repeatability of tumor diameter and SUV uptake: on site and at an imaging clinical research organization (CRO). Tumor volume reads were only performed by CRO. In each reading set, target lesions were independently measured on sequential imaging.

RESULTS

Median time between FDG-PET/CT was two days (range 1-7). For site reads, concordance correlation coefficients (CCC) for SUVmean, SUVmax, and tumor diameter were 0.95, 0.94, and 0.99, respectively. Repeatability coefficients were 16.3%, 17.3%, and 8.8% for SUVmean, SUVmax, and tumor diameter, respectively. Similar results were observed for CRO reads. Tumor volume CCC was 0.99 with a repeatability coefficient of 28.1%.

CONCLUSIONS

There was excellent test-retest repeatability for FDG-PET/CT quantitative measurements across two sites and two independent reading methods. Cutoff values for determining change in SUVmean, SUVmax, and tumor volume establish limits to determine metabolic and/or volumetric response to treatment in platinum-sensitive relapsed ovarian cancer.

Imaging of treatment response to the combination of carboplatin and paclitaxel in human ovarian cancer xenograft tumors in mice using FDG and FLT PET

Introduction

A combination of carboplatin and paclitaxel is often used as first line chemotherapy for treatment of ovarian cancer. Therefore the use of imaging biomarkers early after initiation of treatment to determine treatment sensitivity would be valuable in order to identify responders from non-responders. In this study we describe the non-invasive PET imaging of glucose uptake and cell proliferation using 2-deoxy-2-[¹⁸F]fluoro-D-glucose (FDG) and 3’-deoxy-3’-[¹⁸F]fluorothymidine (FLT) for early assessment of treatment response in a pre-clinical mouse model of human ovarian cancer treated with carboplatin and paclitaxel.

Methods

Invivo uptake of FLT and FDG in human ovarian cancer xenografts in mice (A2780) was determined before treatment with carboplatin and paclitaxel (CaP) and repeatedday 1, 4 and 8 after treatment start. Tracer uptake was quantified using small animal PET/CT. Tracer uptake was compared with gene expression of Ki67, TK1, GLUT1, HK1 and HK2.

Results

Tumors in the CaP group was significantly smaller than in the control group (p=0.03) on day 8. On day 4 FDG SUVmax ratio was significantly lower in the CaP group compared to the control group (105±4% vs 138±9%; p=0.002) and on day 8 the FDG SUVmax ratio was lower in the CaP compared to the control group (125±13% vs 167±13%; p=0.05). On day 1 the uptake of FLT SUVmax ratio was 89±9% in the CaP group and 109±6% in the control group; however the difference was not statistically significant (p=0.08).

Conclusions

Our data suggest that both FDG and FLT PET may be used for the assessment of anti-tumor effects of a combination of carboplatin and paclitaxel in the treatment of ovarian cancer. FLT provides an early and transient signal and FDG a later and more prolonged response. This underscores the importance of optimal timing between treatment and FLT or FDG imaging since treatment response may otherwise be overlooked.

Preoperative fluorine 18 fluorodeoxyglucose tumoral uptake ratio between upper and lower abdomen in primary advanced-stage ovarian cancer

OBJECTIVE

The objective of this study was to assess whether the ratio of upper abdomen (UA) to lower abdomen (LA) (relative to the umbilicus) standardized fluorine 18 fluorodeoxyglucose uptake, as measured by preoperative positron emission tomography and computed tomography, is predictive of recurrence, survival, and suboptimal cytoreduction (residual tumor >1.0 cm) in advanced-stage ovarian cancer (AOC).

METHODS

Positron emission tomography/computed tomography before surgical staging was performed in 159 AOC patients. The ratio between the highest maximum standardized uptake value (SUV(max)) in the UA and the LA was expressed as UA/LA SUV(max). Clinicopathological characteristics and follow-up information were collected retrospectively. Cox proportional hazards analysis was used to identify prognostic factors for recurrence and survival. Logistic regression analysis was used to identify predictors of suboptimal cytoreduction.

RESULTS

The median age and follow-up period were 55 years (range, 27-80 years) and 32 months (range, 1-92 months), respectively; 133 and 26 patients had stage III and IV disease, respectively. There were 120 and 54 cases of recurrence and disease-specific death, respectively. Multivariate analysis showed that recurrence was associated significantly with high UA/LA SUV(max) (P < 0.05; hazard ratio [HR], 4.902; 95% confidence interval [CI], 2.521-9.531) and suboptimal cytoreduction (P < 0.05; HR, 2.431; 95% CI, 1.561-3.788), and that disease-specific death was significantly associated with high UA/LA SUV(max) (P < 0.05; HR, 2.777; 95% CI, 1.270-6.075), suboptimal cytoreduction (P < 0.05; HR, 1.951; 95% CI, 1.080-3.524), and histology (P < 0.05; HR, 4.134; 95% CI, 1.676-10.196). Upper abdomen/lower abdomen SUV(max) was the only independent predictor of suboptimal cytoreduction (P < 0.05; odds ratio, 4.644; 95% CI, 1.676-12.862).

CONCLUSIONS

High preoperative UA/LA SUV(max) was significantly associated with poor prognosis and may be predictive of suboptimal cytoreduction in AOC. This parameter may be considered in the treatment of AOC patients.

Preoperative 18F-FDG PET/CT in the management of advanced epithelial ovarian cancer

OBJECTIVE

The introduction of 18-FDG-PET/CT during preoperative evaluation of patients with epithelial ovarian cancer (EOC) has led to an increase of the detection of extra-abdominal metastases. However, the clinical impact of this upstage remains unclear.

METHODS

Patients with suspected advanced EOC underwent 18-FDG-PET/CT within two weeks prior to debulking surgery.

RESULTS

Between 2006 and 2011 95 patients met the inclusion criteria. Based on the concordance or the discrepancy of clinical and PET/CT stage, patients were divided into 3 groups (A: clinical and PET III; B: clinical III and PET IV; C: clinical and PET IV). Twenty-five patients were upstaged from FIGO stage III to stage IV by PET/CT. The proportion of patients who achieved a residual tumor <1cm in group B and C was similar, whereas it was significantly lower compared to group A. Similarly, complete response to adjuvant chemotherapy was achieved more frequently in patients in group A. PFS was similar in the three groups (17, 17 and 12 months in group A, B and C), as well as OS (51, 41 and 35 months).

CONCLUSIONS

PET/CT is able to detect distant metastases in EOC patients. The presence of extra-abdominal disease probably indicates a more aggressive disease which also shows a lower response to standard chemotherapy. However, upstaged patients have a similar prognosis compared to stage III patients, probably because intra-abdominal disease is more likely to lead patients to death. This might also explain why residual tumor is the most important prognostic factor for advanced EOC patients.

Ovarian carcinomatosis: how the radiologist can help plan the surgical approach

Ovarian carcinoma is the most common cause of death due to gynecologic malignancy. Peritoneal involvement is present in approximately 70% of patients at the time of initial diagnosis. The disease spreads abdominally by direct extension, exfoliation of tumor cells into the peritoneal space, and dissemination of tumor cells along lymphatic pathways. Carcinomatosis characterizes an advanced stage of disease in which peritoneal disease has spread throughout the upper abdomen (stage IIIC) or in which diffuse peritoneal disease is accompanied by malignant pleural infiltration or visceral metastases (stage IV). Common sites of intraperitoneal seeding of ovarian carcinoma include the pelvis, omentum, paracolic gutters, liver capsule, and diaphragm. Soft-tissue thickening, nodularity, and enhancement are all signs of peritoneal involvement. Advanced-stage disease is treated either with initial cytoreductive surgery (debulking) followed by adjuvant chemotherapy, or with initial neoadjuvant chemotherapy followed by debulking. Radiologic imaging plays an important role in the selection of patients who may benefit from neoadjuvant chemotherapy before debulking. However, accurate interpretation of the imaging findings is challenging and requires a detailed knowledge of the complex peritoneal anatomy, directionality of flow of peritoneal fluid, and specific disease sites that are likely to present particular difficulties with regard to surgical access and technique. Although there is as yet no clear consensus on the criteria for resectability of peritoneal lesions, extensive involvement of the small bowel or mesenteric root, involved lymph nodes superior to the celiac axis, pleural infiltration, pelvic sidewall invasion, bladder trigone involvement, and hepatic parenchymal metastases or implants near the right hepatic vein are considered indicative of potential nonresectability. Implants larger than 2 cm in diameter in the diaphragm, lesser sac, porta hepatis, intersegmental fissure, gallbladder fossa, or gastrosplenic or gastrohepatic ligament also may represent nonresectable disease.

Effects of ROI Placement on PET-Based Assessment of Tumor Response to Therapy

Purpose. Quantitative PET response assessment during therapy requires regions of interest (ROI). Commonly, a fixed-size ROI is placed at the maximum uptake point in the pretreatment study. For intratreatment, the ROI is placed either at the maximum uptake point (ROI_peak) or at the same location as the pretreatment ROI (ROI_same). We have evaluated the effects of the ROI placement on response assessment. Methods. PET scans of 15 head and neck cancer patients were used to evaluate the effects of the two ROI methods on response assessment. Results. The average intratreatment ROI_peak uptake was 13.4% higher than the ROI_same uptake (range −14% to 38%). The average relative change in ROI_peak uptake was 7.9% lower than ROI_same uptake (range −5% to 36%), resulting in ambiguous tumour classification in 19% of the tumours. Conclusion. Quantitative PET response assessment using a fixed-size ROI is sensitive the ROI placement. The difference between ROI_peak and ROI_same could be substantial resulting in ambiguous response assessment. Although the fixed-size ROI is simple to implement, it is also prone to the limitations and should be used with caution. Clinical trial data are necessary to establish reliable thresholds for fixed-size ROI techniques and to evaluate their efficacy for response assessment.

Treatment with the MEK inhibitor U0126 induces decreased hyperpolarized pyruvate to lactate conversion in breast, but not prostate, cancer cells

Alterations in cell metabolism are increasingly being recognized as a hallmark of cancer and are being exploited for the development of diagnostic tools and targeted therapeutics. Recently, ¹³C MRS-detectable hyperpolarized pyruvate to lactate conversion has been validated in models as a noninvasive imaging method for the detection of tumors and treatment response, and has successfully passed phase I clinical trials. To date, response to treatment has been associated with a decrease in hyperpolarized lactate production. In this study, we monitored the effect of treatment with the mitogen-activated protein kinase (MEK) inhibitor U0126 in prostate and breast cancer cells. Following treatment, we observed a 31% decrease in the flux of hyperpolarized ¹³C label in treated MCF-7 breast cancer cells relative to controls. In contrast, and unexpectedly, the flux increased to 167% in treated PC3 prostate cancer cells. To mechanistically explain these observations, we investigated treatment-induced changes in the different factors known to affect the pyruvate to lactate conversion. NADH (nicotinamide adenine dinucleotide, reduced form) levels remained unchanged, whereas lactate dehydrogenase expression and activity, as well as intracellular lactate, increased in both cell lines, providing an explanation for the elevated hyperpolarized lactate observed in PC3 cells. The expression of MCT1, which mediates pyruvate transport, decreased in treated MCF-7, but not PC3, cells. This identifies pyruvate transport as rate limiting in U0126-treated MCF-7 cells and explains the decrease in hyperpolarized lactate observed in these cells following treatment. Our findings highlight the complexity of interactions between MEK and metabolism, and the need for mechanistic validation before hyperpolarized ¹³C MRS can be used to monitor treatment-induced molecular responses.

Recognition algorithm for assisting ovarian cancer diagnosis from coregistered ultrasound and photoacoustic images: ex vivo study

Unique features and the underlining hypotheses of how these features may relate to the tumor physiology in coregistered ultrasound and photoacoustic images of ex vivo ovarian tissue are introduced. The images were first compressed with wavelet transform. The mean Radon transform of photoacoustic images was then computed and fitted with a Gaussian function to find the centroid of a suspicious area for shift-invariant recognition process. Twenty-four features were extracted from a training set by several methods, including Fourier transform, image statistics, and different composite filters. The features were chosen from more than 400 training images obtained from 33 ex vivo ovaries of 24 patients, and used to train three classifiers, including generalized linear model, neural network, and support vector machine (SVM). The SVM achieved the best training performance and was able to exclusively separate cancerous from non-cancerous cases with 100% sensitivity and specificity. At the end, the classifiers were used to test 95 new images obtained from 37 ovaries of 20 additional patients. The SVM classifier achieved 76.92% sensitivity and 95.12% specificity. Furthermore, if we assume that recognizing one image as a cancer is sufficient to consider an ovary as malignant, the SVM classifier achieves 100% sensitivity and 87.88% specificity.

New ways of assessing ovarian cancer response: metabolic imaging and beyond

In patients with advanced ovarian cancer, it can be challenging to evaluate response to neoadjuvant chemotherapy on computed tomography (CT) due to disseminated small volume disease and serosal disease. In addition, measuring the change in size of tumour burden takes time in order to allow tumour shrinkage. Despite these challenges, serum CA-125 levels and CT are the standard tools for the assessment of treatment response in ovarian cancer. New functional imaging techniques may allow the identification of response earlier and with higher accuracy. In this review article, we describe the current literature on functional imaging techniques in ovarian cancer response assessment, focusing on fluorodeoxyglucose-positron emission tomography.

Early prediction of survival following induction chemotherapy with DCF (docetaxel, cisplatin, 5-fluorouracil) using FDG PET/CT imaging in patients with locally advanced head and neck squamous cell carcinoma

PURPOSE

Locally advanced head and neck squamous cell carcinoma (HNSCC) has a high rate of recurrence. Induction chemotherapy with DCF (docetaxel, cisplatin, 5-fluorouracil) before chemoradiotherapy could lead to the best disease control of inoperable stage III/IV HNSCC but with an increased risk of acute toxicity. Early assessment of therapeutic efficacy is a key issue in considering the benefit of escalation in a poor prognosis population.

METHODS

Patients with stage III/IV HNSCC, in whom DCF induction chemotherapy followed by concurrent chemoradiotherapy had been validated by a multidisciplinary team, were prospectively included in the study. FDG PET/CT scans were performed in all patients before and after two of the three cycles of DCF. EORTC99 criteria were used to evaluate PET responses as follows: group 1 (metabolic responders) showing a complete response (CR) or partial response (PR), and subgroup 0 (metabolic nonresponders) showing stable disease (SD) or progressive disease (PD). The primary endpoint for monitoring patients was event-free survival (EFS). EFS probabilities between the two groups were estimated by the Kaplan-Meier method and statistically compared using the log-rank test.

RESULTS

Fifteen consecutive patients (14 men, 1 woman; age 57.5 ± 6.2 years, mean ± SD) were analysed. Therapeutic assessment by PET/CT demonstrated CR in four patients, PR in six, SD in four and PD in one. Among the ten patients with a metabolic response (group 1), none had relapsed at the time of this report, while four of five patients with no metabolic response (group 0) showed recurrence within an average of 9.0 ± 1.6 months. Median EFS was, respectively, 18.9 months (3.8-25.3 months) and 10.2 months (7.5-12.7 months) in group 1 and group 0. The corresponding 1-year EFS rates were 100 % and 20 %, respectively. The difference in EFS between the two groups was statistically significant (p = 0.0014).

CONCLUSION

Early therapeutic response demonstrated on FDG PET/CT after two cycles of induction chemotherapy with DCF in patients with inoperable stage III/IV HNSCC seems to be a predictive factor for EFS.

Impact of FDG-PET and -PET/CT imaging in the clinical decision-making of ovarian carcinoma: an evidence-based approach

The most definitive role of fluorodeoxyglucose (FDG)-PET/computed tomography (CT) at present is surveillance and detecting recurrence in patients who have completed primary therapy but demonstrate a rising serum tumor marker (e.g., CA-125 levels). In this scenario, PET/CT demonstrates high sensitivity and accuracy in detecting lesions that are otherwise challenging, and appears superior (with less interobserver variability) compared with CT alone. Despite the fact that peritoneal deposits may be missed by PET/CT, the overall performance is better than CT alone. FDG-PET does not play a significant additional role in the primary diagnosis of ovarian cancers; however, the role of combined PET/CT modality has recently begun to be re-explored for initial disease staging, particularly because PET/CT can pick up small unsuspected lesions and thereby provide a better disease assessment of the whole body in a single examination. The baseline PET/CT also subserves an important role for future monitoring of therapy response. Therapy monitoring by PET could help to optimize neoadjuvant therapy protocols and to avoid ineffective therapy in nonresponders early in its course, although PET/CT has cost-effectiveness issues that need further evaluation. The prognostic value of FDG-PET/CT has been investigated in the following areas: in the preoperative setting to predict optimal cytoreduction; to assess the value of a positive FDG-PET following primary surgery; and when employed as a replacement for second-look laparotomy following completion of primary surgery and chemotherapy. The data, although promising, are still sparse in all the three domains for a definite recommendation.

The role of FDG-PET/CT in gynaecological cancers

There is now a growing body of evidence supporting the use of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in gynaecological malignancies. Although this molecular imaging technique is becoming increasingly available, PET/CT remains an expensive imaging tool. It is essential to be familiar with the circumstances in which FDG-PET/CT can add value and contribute to patient management and indeed to know when it is unlikely to be of benefit. It is also important to understand and recognize the potential pitfalls. FDG-PET/CT has been most widely adopted for staging patients with suspected advanced disease or in suspected recurrence, offering a whole-body imaging approach. However, there is great potential for this technique to act as a predictive biomarker of response to treatment, as well as a prognostic biomarker. In addition, FDG-PET images may now be incorporated into radiotherapy planning in order to refine the delineation of dose according to metabolically active sites of disease. This article reviews the literature that provides the evidence for the use of FDG-PET in gynaecological malignancies, identifies areas of real benefit and future potential, and highlights circumstances where there is limited value.

18F-FDG-PET/CT Imaging as an early survival predictor in patients with primary high-grade soft tissue sarcomas undergoing neoadjuvant therapy

PURPOSE

Neoadjuvant therapy is associated with considerable toxicity and limited survival benefits in patients with soft tissue sarcoma (STS). We prospectively evaluated whether 2[18F]fluoro-2-deoxy-d-glucose ((18)F-FDG)-PET/computed tomographic (CT) imaging after the initial cycle of neoadjuvant therapy could predict overall survival in these patients.

EXPERIMENTAL DESIGN

Thirty-nine patients underwent (18)F-FDG-PET/CT before and after one cycle of neoadjuvant therapy. Fifty-six patients underwent end-of-treatment PET. Overall survival was, among others, correlated with changes of SUV(peak) and histopathology.

RESULTS

One-, two-, and five-year survival rates were 95% ± 3.0%, 86% ± 4.6%, and 68% ± 6.6%, respectively. Median time to death was 30.9 months (mean, 27.7; range, 6.9-50.1). Optimal cutoff values for early and late decreases in SUV(peak) (26% and 57%, respectively) were significant predictors of survival in univariate survival analysis [P = 0.041; HR, 0.27; 95% confidence interval (CI), 0.08-0.95 and P = 0.045; HR, 0.31; 95% CI, 0.10-0.98]. Seven of 15 early PET nonresponders but only four of 24 early PET responders died during follow-up (P = 0.068). The only other significant survival predictor was surgical margin positivity (P = 0.041; HR, 3.31; 95% CI, 1.05-10.42). By multivariable analysis, early metabolic response (P = 0.016) and positivity of surgical margins (P = 0.036) remained significant survival predictors.

CONCLUSION

(18)F-FDG-PET predicted survival after the initial cycle of neoadjuvant chemotherapy in patients with STS and can potentially serve as an intermediate endpoint biomarker in clinical research and patient care.

Role of New Functional MRI Techniques in the Diagnosis, Staging, and Followup of Gynecological Cancer: Comparison with PET-CT

Recent developments in diagnostic imaging techniques have magnified the role and potential of both MRI and PET-CT in female pelvic imaging. This article reviews the techniques and clinical applications of new functional MRI (fMRI) including diffusion-weighted MRI (DWI), dynamic contrast-enhanced (DCE)-MRI, comparing with PET-CT. These new emerging provide not only anatomic but also functional imaging, allowing detection of small volumes of active tumor at diagnosis and early disease relapse, which may not result in detectable morphological changes at conventional imaging. This information is useful in distinguishing between recurrent/residual tumor and post-treatment changes and assessing treatment response, with a clear impact on patient management. Both PET-CT and now fMRI have proved to be very valuable tools for evaluation of gynecologic tumors. Most papers try to compare these techniques, but in our experience both are complementary in management of these patients. Meanwhile PET-CT is superior in diagnosis of ganglionar disease; fMRI presents higher accuracy in local preoperative staging. Both techniques can be used as biomarkers of tumor response and present high accuracy in diagnosis of local recurrence and peritoneal dissemination, with complementary roles depending on histological type, anatomic location and tumoral volume.