Combined PET/CT for detecting recurrent ovarian cancer limited to retroperitoneal lymph nodes

A Perspective Review: Analyzing Collagen Alterations in Ovarian Cancer by High-Resolution Optical Microscopy

High-grade serous ovarian cancer (HGSOC) is the predominant subtype of ovarian cancer (OC), occurring in more than 80% of patients diagnosed with this malignancy. Histological and genetic analysis have confirmed the secretory epithelial of the fallopian tube (FT) as a major site of origin of HGSOC. Although there have been significant strides in our understanding of this disease, early stage detection and diagnosis are still rare. Current clinical imaging modalities lack the ability to detect early stage pathogenesis in the fallopian tubes and the ovaries. However, there are several microscopic imaging techniques used to analyze the structural modifications in the extracellular matrix (ECM) protein collagen in ex vivo FT and ovarian tissues that potentially can be modified to fit the clinical setting. In this perspective, we evaluate and compare the myriad of optical tools available to visualize these alterations and the invaluable insights these data provide on HGSOC initiation. We also discuss the clinical implications of these findings and how these data may help novel tools for early diagnosis of HGSOC.

18F-FDG PET/MRI and 18F-FDG PET/CT for the Management of Gynecological Malignancies: A Comprehensive Review of the Literature

OBJECTIVE

Positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro- D-glucose integrated with computed tomography (18F-FDG PET/CT) or magnetic resonance imaging (18F-FDG PET/MRI) has emerged as a promising tool for managing various types of cancer. This review study was conducted to investigate the role of 18F- FDG PET/CT and FDG PET/MRI in the management of gynecological malignancies.

SEARCH STRATEGY

We searched for relevant articles in the three databases PubMed/MEDLINE, Scopus, and Web of Science.

SELECTION CRITERIA

All studies reporting data on the FDG PET/CT and FDG PET MRI in the management of gynecological cancer, performed anywhere in the world and published exclusively in the English language, were included in the present study.

DATA COLLECTION AND ANALYSIS

We used the EndNote software (EndNote X8.1, Thomson Reuters) to list the studies and screen them on the basis of the inclusion criteria. Data, including first author, publication year, sample size, clinical application, imaging type, and main result, were extracted and tabulated in Excel. The sensitivity, specificity, and diagnostic accuracy of the modalities were extracted and summarized.

MAIN RESULTS

After screening 988 records, 166 studies published between 2004 and 2022 were included, covering various methodologies. Studies were divided into the following five categories: the role of FDG PET/CT and FDG-PET/MRI in the management of: (a) endometrial cancer (n = 30); (b) ovarian cancer (n = 60); (c) cervical cancer (n = 50); (d) vulvar and vagina cancers (n = 12); and (e) gynecological cancers (n = 14).

CONCLUSIONS

FDG PET/CT and FDG PET/MRI have demonstrated potential as non-invasive imaging tools for enhancing the management of gynecological malignancies. Nevertheless, certain associated challenges warrant attention.

Assessing the roles of collagen fiber morphology and matrix stiffness on ovarian cancer cell migration dynamics using multiphoton fabricated orthogonal image-based models

Ovarian cancer remains the deadliest of the gynecological cancers, where this arises from poor screening and imaging tools that can detect early disease, and also limited understanding of the structural and functional aspects of the tumor microenvironment. To gain insight into the underlying cellular dynamics, we have used multiphoton excited fabrication to create Second Harmonic Generation (SHG) image-based orthogonal models from collagen/GelMA that represent both the collagen matrix morphology and stiffness (∼2-8 kPa) of normal ovarian stroma and high grade serous ovarian cancers (HGSOC). These scaffolds are used to study migration/cytoskeletal dynamics of normal (IOSE) and ovarian cancer (OVCA433) cell lines. We found that the highly aligned fiber morphology of HGSOC promotes aspects of motility (motility coefficient, motility, and focal adhesion expression) through a contact guidance mechanism and that stiffer matrix further promotes these same processes through a mechanosensitive mechanism, where these trends were similar for both normal and cancer cells. However, cell specific differences were found on these orthogonal models relative to those providing only morphology, showing the importance of presenting both morphology and stiffness cues. Moreover, we found increased cadherin expression and decreased cell alignment only for cancer cells on scaffolds of intermediate modulus suggesting different stiffness-dependent mechanotransduction mechanisms are engaged. This overall approach affords decoupling the roles of matrix morphology, stiffness and cell genotype and affords hypothesis testing of the factors giving rise to disease progression and metastasis. Further, more established fabrication techniques cannot simultaneously reproduce both the 3D collagen fiber morphology and stiffness. STATEMENT OF SIGNIFICANCE: Ovarian cancer metastasizes when lesions are small, where cells exfoliate from the surface of the ovary and reattach at distal sites in the peritoneum. The adhesion/migration dynamics are not well understood and there is a need for new 3D in vitro models of the extracellular matrix to study the biology. Here we use multiphoton excited crosslinking to fabricate ECM orthogonal models that represent the collagen morphology and stiffness in human ovarian tissues. These are then used to study ovarian cancer cell migration dynamics and we found that contact guidance and a mechanosensitive response and cell genotype all combine to affect the behavior. These models provide insight into disease etiology and progression not readily possible by other fabrication methods.

Evaluation of Collagen Alterations in Early Precursor Lesions of High Grade Serous Ovarian Cancer by Second Harmonic Generation Microscopy and Mass Spectrometry

Simple Summary

The collagen architecture in the extracellular matrix (ECM) is highly remodeled in high grade serous ovarian cancer (HGSOC). Many of these tumors begin in the fallopian tubes (FT) before metastasizing to the ovaries and it is important to study ECM alterations in carcinogenesis. Here, we used Second Harmonic Generation (SHG) microscopy to classify changes in the collagen fiber morphology in normal FT, and precursor pure p53 signatures and serous tubal intraepithelial carcinoma (STICs) in tissues with no HGSOC. Using a machine learning approach based on image features, we were able to discriminate the tissue groups with good classification accuracy. We additionally performed mass spectrometry analysis of normal and HGSOC tissues to associate the differential expression of collagen isoforms with fiber morphology alterations. This work provides new insights into ECM remodeling in early stage HGSOC and suggests the combined use of SHG microscopy and mass spectrometry as a new diagnostic/prognostic approach.

Abstract

Background: The collagen architecture in high grade serous ovarian cancer (HGSOC) is highly remodeled compared to the normal ovary and the fallopian tubes (FT). We previously used Second Harmonic Generation (SHG) microscopy and machine learning to classify the changes in collagen fiber morphology occurring in serous tubal intraepithelial carcinoma (STIC) lesions that are concurrent with HGSOC. We now extend these studies to examine collagen remodeling in pure p53 signatures, STICs and normal regions in tissues that have no concurrent HGSOC. This is an important distinction as high-grade disease can result in distant collagen changes through a field effect mechanism. Methods: We trained a linear discriminant model based on SHG texture and image features as a classifier to discriminate the tissue groups. We additionally performed mass spectrometry analysis of normal and HGSOC tissues to associate the differential expression of collagen isoforms with collagen fiber morphology alterations. Results: We quantified the differences in the collagen architecture between normal tissue and the precursors with good classification accuracy. Through proteomic analysis, we identified the downregulation of single α-chains including those for Col I and III, where these results are consistent with our previous SHG-based supramolecular analyses. Conclusion: This work provides new insights into ECM remodeling in early ovarian cancer and suggests the combined use of SHG microscopy and mass spectrometry as a new diagnostic/prognostic approach.

Diagnostic performance of PET/CT and PET/MR in the management of ovarian carcinoma-a literature review

Ovarian cancer is a challenging disease. It often presents at an advanced stage with frequent recurrence despite optimal management. Accurate staging and restaging are critical for improving treatment outcomes and determining the prognosis. Imaging is an indispensable component of ovarian cancer management. Hybrid imaging modalities, including positron emission tomography/computed tomography (PET/CT) and PET/magnetic resonance imaging (MRI), are emerging as potential non-invasive imaging tools for improved management of ovarian cancer. This review article discusses the role of PET/CT and PET/MRI in ovarian cancer.

Role of Collagen Fiber Morphology on Ovarian Cancer Cell Migration Using Image-Based Models of the Extracellular Matrix

Remodeling of the extracellular matrix (ECM) is an important part in the development and progression of many epithelial cancers. However, the biological significance of collagen alterations in ovarian cancer has not been well established. Here we investigated the role of collagen fiber morphology on cancer cell migration using tissue engineered scaffolds based on high-resolution Second-Harmonic Generation (SHG) images of ovarian tumors. The collagen-based scaffolds are fabricated by multiphoton excited (MPE) polymerization, which is a freeform 3D method affording submicron resolution feature sizes (~0.5 µm). This capability allows the replication of the collagen fiber architecture, where we constructed models representing normal stroma, high-risk tissue, benign tumors, and high-grade tumors. These were seeded with normal and ovarian cancer cell lines to investigate the separate roles of the cell type and matrix morphology on migration dynamics. The primary finding is that key cell–matrix interactions such as motility, cell spreading, f-actin alignment, focal adhesion, and cadherin expression are mainly determined by the collagen fiber morphology to a larger extent than the initial cell type. Moreover, we found these aspects were all enhanced for cells on the highly aligned, high-grade tumor model. Conversely, the weakest corresponding responses were observed on the more random mesh-like normal stromal matrix, with the partially aligned benign tumor and high-risk models demonstrating intermediate behavior. These results are all consistent with a contact guidance mechanism. These models cannot be synthesized by other conventional fabrication methods, and we suggest this approach will enable a variety of studies in cancer biology.

Isolated lymph node recurrence in epithelial ovarian cancer: Recurrence with better prognosis?

INTRODUCTION

The aim of this study was to compare overall survival (OS) between women with isolated lymph node recurrence (ILNR) and those with isolated peritoneal localization of recurrence (ICR), in patients managed for epithelial ovarian cancer.

METHODS

Data from 1508 patients with ovarian cancer were collected retrospectively from1 January 2000 to 31 December 2016, from the FRANCOGYN database, pooling data from 11 centres specialized in ovary treatment. Median overall survival was determined using the Kaplan-Meier method. Univariate and multivariate analyses were performed to define prognostic factors of overall survival. Patients included had a first recurrence defined as ILNR or ICR during their follow up.

RESULTS

79 patients (5.2 %) presented with ILNR, and 247 (16.4 %) patients had isolated carcinomatosis recurrence. Complete lymphadenectomy was performed more frequently in the ILNR group vs. the ICR group (67.1 % vs. 53.4 %, p = 0.004) and the number of pelvic lymph nodes involved was higher (2.4 vs. 1.1, p = 0.008). The number of involved pelvic LN was an independent predictor of ILNR (OR = 1.231, 95 % CI [1.074-1.412], p = 0.0024). The 3-year and 5-year OS rates in the ILNR group were 85.2 % and 53.7 % respectively, compared to 68.1 % and 46.8 % in patients with ICR. There was no significant difference in terms of OS after initial diagnosis (p = 0.18). 3- year and 5-year OS rates after diagnosis of recurrence were 62.6 % and 15.6 % in the ILNR group, and 44 % and 15.7 % in patients with ICR (p = 0.21).

CONCLUSION

ILNR does not seem to be associated with a better prognosis in terms of OS.

Campagnola P. Imaging Collagen Alterations in STICs and High Grade Ovarian Cancers in the Fallopian Tubes by Second Harmonic Generation Microscopy

The majority of high-grade serous ovarian cancers originate in the fallopian tubes, however, the corresponding structural changes in the extracellular matrix (ECM) have not been well-characterized. This information could provide new insight into the carcinogenesis and provide the basis for new diagnostic tools. We have previously used the collagen-specific Second Harmonic Generation (SHG) microscopy to probe collagen fiber alterations in high-grade serous ovarian cancer and in other ovarian tumors, and showed they could be uniquely identified by machine learning approaches. Here we couple SHG imaging of serous tubal intra-epithelial carcinomas (STICs), high-grade cancers, and normal regions of the fallopian tubes, using three distinct image analysis approaches to form a classification scheme based on the respective collagen fiber morphology. Using a linear discriminant analysis, we achieved near 100% classification accuracy between high-grade disease and the other tissues, where the STICs and normal regions were differentiated with ~75% accuracy. Importantly, the collagen in high-grade disease in both the fallopian tube and the ovary itself have a similar collagen morphology, further substantiating the metastasis between these sites. This analysis provides a new method of classification, but also quantifies the structural changes in the disease, which may provide new insight into metastasis.

Classification of human ovarian cancer using functional, spectral, and imaging features obtained from in vivo photoacoustic imaging

We report in this pilot study the diagnostic results of in vivo imaging of patients with ovarian lesions, using a co-registered photoacoustic and ultrasound (PAT/US) system. A total of 39 ovaries from 24 patients were imaged in vivo. PAT functional features, i.e., blood oxygen saturation (sO2) and relative total hemoglobin (rHbT), PAT image features, and PAT spectral features within a region of interest (ROI) in each ovarian tissue were extracted. To select the significant features, a t-test on each feature was performed, and the independent predictors were determined by evaluating correlation between each pair of predictors. To classify the ovarian lesions, we employed a generalized linear model (GLM) and a support vector machine (SVM). We used these classifiers first to distinguish benign/normal lesions from ovaries with invasive epithelial tumors and then to separate normal/benign lesions from all types of ovarian tumors. We developed classifiers once by inclusion of PAT functional features to assess the best diagnostic performance of the classifiers when multiple wavelengths data are available. Second time, we excluded the PAT functional features from the features set to evaluate the best diagnostic performance if only a single wavelength is available. Our results show that using functional features improves the classification performance, especially for distinguishing normal/benign ovarian lesions from all types of tumors. In this case, an area under ROC curve (AUC) of 0.92, 0.93 of testing data was achieved using a GLM and SVM classifier when functional features were included in the feature set while excluding these features resulted in an AUC of 0.89, 0.92, respectively.

Polarization-resolved second harmonic generation imaging of human ovarian cancer

Remodeling of the extracellular matrix in human ovarian cancer can be manifested in increased collagen concentration, changes in alignment within fibrils/fibers and/or up-regulation of different collagen isoforms. We used pixel-based second harmonic generation (SHG) polarization microscopy analyses to probe these molecular changes in human ovarian tissues [normal stroma, benign tumors, and high-grade serous (HGS) tumors] by: (i) determination of the α-helical pitch angle via the single-axis molecular model, (ii) collagen alignment within fibrils via SHG anisotropy, and (iii) chirality via SHG circular dichroism (SHG-CD). Pixel approaches are required due to the complex structure of the matrix that lacks a high degree of fiber alignment. The largest differences in the helical pitch angle were between normal stroma and benign tumors, consistent with gene expression showing the Col III isoform is up-regulated in the latter. The data were not consistent with up-regulation of Col III in HGS tumors as previous reports have suggested. The different tissues also displayed differing SHG anisotropies and SHG-CD responses, consistent with either Col III incorporation or randomization of Col I alignment within benign and malignant tumors. Additionally, the high-grade tumors displayed higher collagen concentration, where this desmoplasia is consistent with the higher fiber density in these tissues. These results collectively indicate that the fibril assemblies are distinct in all tissues, where these differences likely result from the synthesis of collagen rather than remodeling of existing collagen. Importantly, these analyses are label-free and interrogate subresolution collagen structure on intact tissues, without the need for conventional structural biology tools.

Fludeoxyglucose F 18 PET/CT Assessment of Ovarian Cancer

Ovarian cancer is one of the most common gynecologic cancers and one of the leading causes of cancer death in women. It is often asymptomatic in early stages, and thus most patients are diagnosed when it is of advanced stage. For these reasons, the role of biomarkers and tomographic imaging is crucial. Fludeoxyglucose F 18 PET/CT is a useful imaging modality in different clinical settings of the disease, overcoming some limits of conventional imaging and influencing prognosis and therapeutic approaches. PET/MR imaging is an emerging modality, and its potential role remains to be explored.

Assessing local stromal alterations in human ovarian cancer subtypes via second harmonic generation microscopy and analysis

The collagen architecture in all human ovarian cancers is substantially remodeled, where these alterations are manifested in different fiber widths, fiber patterns, and fibril size and packing. Second harmonic generation (SHG) microscopy has differentiated normal tissues from high-grade serous (HGS) tumors with high accuracy; however, the classification between low-grade serous, endometrioid, and benign tumors was less successful. We postulate this is due to known higher genetic variation in these tissues relative to HGS tumors, which are genetically similar, and this results in more heterogeneous collagen remodeling in the respective matrix. Here, we examine fiber widths and SHG emission intensity and directionality locally within images (e.g., 10×10  microns) and show that normal tissues and HGS tumors are more uniform in fiber properties as well as in fibril size and packing than the other tissues. Moreover, these distributions are in good agreement with phase matching considerations relating SHG emission directionality and intensity. The findings show that in addition to average collagen assembly properties the intrinsic heterogeneity must also be considered as another aspect of characterization. These local analyses showed differences not shown in pure intensity-based image analyses and may provide further insight into disease etiology of the different tumor subtypes.

Delineation of retroperitoneal metastatic lymph nodes in ovarian cancer with near-infrared fluorescence imaging

Lymph node metastasis occurs in early-stage and late-stage ovarian cancers. Systematic lymphadenectomy is frequently conducted in an attempt to prevent disease progression. However, this method is associated with multiple complications. Therefore, it is necessary to develop a less invasive and more sensitive method for detecting lymphatic metastasis in ovarian cancer. The aim of the present study was to develop an appropriate fluorescent label for the analysis of lymphatic metastasis in vivo. To this end, epithelial ovarian cancer cells with high potential for lymph node metastasis were labeled using mCherry fluorescence. The cells were then imaged in vitro to determine the expression of mCherry, and in a mouse xenograft model in vivo. The data demonstrated the successful identification of metastatic retroperitoneal lymph nodes by co-localization with lymph nodes labeled by near-infrared fluorescence nanoparticles in vivo. These data provided important insights into the further development of methods for intra-operative identification of lymphatic metastasis and the mechanisms underlying lymphatic metastasis.

Diagnostic value of positron emission tomography (PET) and PET/computed tomography in recurrent/metastatic ovarian cancer: A meta-analysis

AIM

The study was conducted to assess and compare the overall diagnostic value of positron emission tomography (PET) alone and PET/computed tomography (CT) for the detection of recurrent/metastatic ovarian cancer.

METHODS

A systematic literature search in PubMed, EMBASE and Chinese literature databases (CNKI, VIP and Wanfang) up to August 2014 was performed to identify relevant articles. The diagnostic performance of PET alone or PET/CT was assessed in terms of the following evaluation indexes: summary sensitivity, specificity, positive and negative likelihood ratio, diagnostic odds ratio and area under the curve summary receiver operating characteristics.

RESULTS

Sixty-four studies with 3722 patients were included in this meta-analysis. Favorable results were obtained for both PET/CT and PET alone with similar sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio and area under the curve in diagnosing recurrent/metastatic ovarian cancer (P > 0.05). However, the sensitivity of PET/CT was significantly higher than PET alone in European patients.

CONCLUSIONS

Both PET and PET/CT have promising diagnostic value in recurrent/metastatic ovarian cancer. The diagnostic performance of PET/CT may be superior to PET alone in European 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.

3D texture analysis for classification of second harmonic generation images of human ovarian cancer

Remodeling of the collagen architecture in the extracellular matrix (ECM) has been implicated in ovarian cancer. To quantify these alterations we implemented a form of 3D texture analysis to delineate the fibrillar morphology observed in 3D Second Harmonic Generation (SHG) microscopy image data of normal (1) and high risk (2) ovarian stroma, benign ovarian tumors (3), low grade (4) and high grade (5) serous tumors, and endometrioid tumors (6). We developed a tailored set of 3D filters which extract textural features in the 3D image sets to build (or learn) statistical models of each tissue class. By applying k-nearest neighbor classification using these learned models, we achieved 83–91% accuracies for the six classes. The 3D method outperformed the analogous 2D classification on the same tissues, where we suggest this is due the increased information content. This classification based on ECM structural changes will complement conventional classification based on genetic profiles and can serve as an additional biomarker. Moreover, the texture analysis algorithm is quite general, as it does not rely on single morphological metrics such as fiber alignment, length, and width but their combined convolution with a customizable basis set.

Management of epithelial ovarian cancer from diagnosis to restaging: an overview of the role of imaging techniques with particular regard to the contribution of 18F-FDG PET/CT

Epithelial ovarian carcinoma is a major form of cancer affecting women in the western world. The silent nature of this disease results in late presentation at an advanced stage in many patients. It is therefore important to assess the role of imaging techniques in the management of these patients. This article presents a review of the literature on the role of (18)F-FDG-PET/CT in the different stages of management of epithelial ovarian cancer. Moreover, a comparison with other imaging techniques has been made and the relationship between (18)F-PET/CT and the assay of serum CA-125 levels has been discussed.

Recurrent ovarian cancer with multiple lymph nodes metastases successfully treated with lymphadenectomy as secondary cytoreductive surgery: A case report

INTRODUCTION

Occasionally, lymph node metastases represent the only component at the time of recurrence of ovarian cancer. Here we report the case of a 78-year-old Japanese female who underwent successful surgery for recurrent ovarian cancer with multiple lymph node metastases.

PRESENTATION OF CASE

The patient was referred to our institution with recurrent disease accompanied by chemoresistant multiple retroperitoneal lymph node metastases five years after the initial therapy for stage IIIc serous adenocarcinoma of the ovary. Positron emission tomography/computed tomography (PET/CT) revealed the involvement of two para-aortic nodes and two pelvic nodes, with no other positive site. The patient underwent systematic para-aortic and pelvic lymphadenectomy, and the metastatic nodes were completely resected. Histopathological examination revealed metastatic high-grade adenocarcinoma in four of 63 dissected lymph node specimens. The patient has been in clinical remission for over four years without any further additional therapies.

DISCUSSION

In our case, the metastatic nodes predicted by PET/CT completely corresponded to the actual metastatic nodes; however, PET/CT often fails to identify microscopic disease in pathological positive nodes. We cannot reliably predict whether lymph node metastasis will persist in the limited range. Therefore, systematic lymphadenectomy with therapeutic intent should be performed, although it does not always mean that we remove all cancer cells.

CONCLUSION

The findings from this case suggest that, even if used as secondary cytoreductive surgery in the context of a recurrent disease, systematic aortic and pelvic node dissection might sometimes contribute to the control if not cure of ovarian cancer.

Positron emission tomography in gynecological malignancies

Positron emission tomography (PET) is a functional diagnostic imaging technique. F-18 fluoro-2-deoxy-d-glucose (FDG) is a commonly used radiopharmaceutical that is an analog of glucose. PET with FDG is now the standard of care in initial staging, monitoring the response to the therapy and management of various cancers. There is not sufficient data to support the use of PET in the initial diagnosis of cervical cancer; however, FDG-PET has a role in initial staging in the detection of distant metastases in patients with cervical cancer. PET has limited value in lesion localization in early stages of ovarian cancer, but plays a significant role in identifying recurrent tumors in patients with rising tumor markers. In this article, the clinical application of PET in gynecological malignancies is reviewed.

High impact of FDG-PET/CT in diagnostic strategies for ovarian cancer

BACKGROUND

Ovarian cancer has the highest mortality of all gynecologic malignancies. FDG-PET/CT was proven to be accurate for identification of primary ovarian tumors, regional lymph nodes, and distant metastases.

PURPOSE

To evaluate ovarian masses at FDG-PET/CT in correlation with histopathologic findings.

MATERIAL AND METHODS

Ninety-eight patients underwent whole body FDG-PET/CT examination. Eighty-six patients with primary ovarian cancer and 12 patients with metastatic disease to the ovaries were included.

RESULTS

PET/CT imaging was true-positive in 87/94 patients with malignant tumors. In 4/4 patients with benign tumors, PET/CT results were true-negative, with sensitivity of 92.6%, specificity 100%, total test accuracy 92.9%. Fifty-seven patients were diagnosed as stage IV ovarian cancer with distant metastasis.

CONCLUSION

The anatomical/functional examination by FDG-PET/CT was proven to be valuable in increasing the diagnostic accuracy that can help improve patient management.

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.

Recurrent ovarian cancer presenting in the right supraclavicular lymph node with isolated metastasis: a case report

Introduction

The majority of ovarian cancer recurrences are in the abdomen. However, some cases relapse as isolated lymph node metastases, mostly in pelvic or para-aortic nodes. Peripheral isolated lymph node metastasis is rare.

Case presentation

A 69-year-old Japanese woman had recurrent ovarian cancer presenting with isolated right supraclavicular lymph node metastasis. After surgical resection and combination chemotherapy with carboplatin and paclitaxel, her right supraclavicular lymph node completely regressed.

Conclusions

Peripheral isolated lymph nodes, including right supraclavicular lymph node, can recur without a macroscopic abdominal lesion. Clinicians should carefully examine peripheral lymph nodes for recurrence.

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.

Long Term Prognostic Implications of Expression of Glucose Transporter-1 and Hexokinase II in Patients with Stage I Uterine Leiomyosarcoma

Many malignant epithelial tumors show increased expression of glucose transporter-1 (GLUT-1) and hexokinase II (HK-II), both of which are involved in glucose metabolism. GLUT-1 levels are often correlated with prognosis in these tumors. The current retrospective study was conducted to evaluate the importance of GLUT-1 and HK-II expression in leiomyosarcoma (LMS), a malignant uterine non-epithelial tumor with a poor prognosis. The subjects were 23 patients with stage I LMS. Expression of GLUT-1 and HK-II was evaluated immunohistochemically in samples removed surgically, and the MIB-1 index was evaluated as a measure of cell proliferation. The association of these results with prognosis was examined. Twenty samples of leiomyoma (LOM), a benign non-epithelial tumor, were used as controls. Immunohistochemical expression was defined as negative staining (–), weak to sporadic staining (1+), and strong staining (2+) per microscopic field, respectively. Malignancy was evaluated in 2000 cells and the MIB-1 index was calculated. Overall survival for LMS was estimated using the Kaplan-Meier method. Of the LMS cases, 12 were GLUT-1-positive (52.2%; 2+: 2, 1+: 10) and 15 were HK-II-positive (65.2%; 2+: 1, 1+: 14). GLUT-1 expression in LMS was significantly correlated with the MIB1 index. The 10-year survival rates were 90.9% and 58.3% in GLUT-1-negative and GLUT-1-positive cases, respectively, and 75.0% and 73.3% in HK-II-positive and HK-II-negative cases, respectively. GLUT-1 expression was significantly correlated with prognosis. Cases of stage I LMS showed a significant correlation between the expression level of GLUT-1 and the MIB-1 index, an indicator of malignancy. GLUT-1-negative cases had a better prognosis than GLUT-1-positive cases, suggesting that GLUT-1 expression is an effective prognostic marker.

Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT scans for diagnosing ovarian cancer recurrence

OBJECTIVE

To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated 18F-fluorodeoxyglucose (FDG)-PET/CT studies for restaging of ovarian cancer.

MATERIALS AND METHODS

One hundred and twenty women who had undergone treatment for ovarian cancer underwent a conventional PET/CT scans with ldCT, and then ceCT. Two observers interpreted and decided in consensus on the PET/ldCT and PET/ceCT images by a 3-point scale (N: negative, E: equivocal, P: positive) per patient and lesion site. Final diagnoses were obtained by histopathological examinations, or clinical follow-up for at least 6 months.

RESULTS

Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET/ceCT was 86.9% (40/46), 95.9% (71/74), and 92.5% (111/120), respectively, whereas those of PET/ldCT were 78.3% (36/46), 95.0% (70/74), and 88.3% (106/120), respectively. All sensitivity, specificity, and accuracy significantly differed between two methods (McNemar test, p<0.0005, p=0.023, and p<0.0001, respectively). The scales of detecting 104 recurrent lesion sites were N:14, E:6, P:84 for PET/ceCT, and N:15, E:17, P:72 for PET/ldCT, respectively. Eleven equivocal and one negative regions by PET/ldCT were correctly interpreted as positive by PET/ceCT.

CONCLUSION

PET/ceCT is a more accurate imaging modality with higher confidence for assessing ovarian cancer recurrence than PET/ldCT.

Follow-up with CA125 after primary therapy of advanced ovarian cancer: in favor of continuing to prescribe CA125 during follow-up

Serum cancer antigen 125 (CA125) is widely used in ovarian cancer to monitor the effectiveness of therapy both in first line and recurrence. It is also widely used during follow-up, where it is able to identify a percentage of patients with asymptomatic recurrence. Although a recent Medical Research Council (UK)/European Organisation for Research and Treatment of Cancer trial has demonstrated that early chemotherapy in asymptomatic patients based only on CA125 increase does not prolong survival, we still believe that CA125 monitoring should be prescribed to patients during follow-up. In fact, it can help to identify patients who should undergo radiology in order to select those that can benefit from surgery or from early treatment before the onset of symptoms, which are usually related to an excessive disease burden. The delay of disease symptoms, such as those associated with the appearance of ascites or bowel occlusion, is in our view an important goal of our treatment of recurrence. Moreover, research should be done in patients with asymptomatic CA125 increase in order to identify more effective therapies that will improve survival. Finally, the reliability of CA125 as a surrogate of response under treatment with biological agents should be validated in prospective trials.

PET/CT imaging in gynecologic malignancies: a critical overview of its clinical impact and our retrospective single center analysis

Gynecologic cancers represent a major global healthcare problem since they are associated with a significant mortality and morbidity. Over the last decade, considerable efforts have been spent in the development and optimization of novel diagnostic modalities to achieve an early diagnosis, aid in choosing appropriate treatment, improving long term surveillance, with the ultimate goal of increasing survival of gynecologic cancer patients. A growing body of evidence defines PET/CT as one of the most powerful tools for tumor, nodal and metastasis (TNM) cancer staging both in pre-treatment and in post treatment follow-up settings. At any phase of cancer evaluation, detection of metastasis represents one of the most critical impediments to the cure of tumor; traditional diagnostic imaging modalities, such as computed tomography (CT), are frequently found to inadequately stage the tumor, based on subsequent outcomes. As a consequence, patients may undergo pointless surgery for disease that could be treated with local medical therapies. In the setting of restaging, the ability to describe primary lesion, lymph nodes, possible metastases to peritoneum, bone, liver, lungs and brain renders PET/CT a potential alternative for a series of tests, including bone scanning, MRI or ultrasound, diagnostic CT, lymph node surgical sampling, that need to be used in combination in order to obtain a level of clinical confidence. In this review, we describe, the theoretical advantage and prognostic implications of PET/CT in the management of gynecologic cancer patients.

Potential role of coregistered photoacoustic and ultrasound imaging in ovarian cancer detection and characterization

Currently, there is no adequate technology to detect early stage ovarian cancers. Most of the cancers in the ovary are detected when the cancer has already metastasized to other parts of the body. As a result, ovarian cancer has the highest mortality of all gynecologic cancers with a 5-year survival rate of 30% or less. Thus, there is an urgent need to improve the current diagnostic techniques. Photoacoustic imaging (PAI) is an emerging modality with a great potential to assist ultrasound for detecting ovarian cancer noninvasively. In this article, we report the first study of coregistered ultrasound and PAI of 33 ex vivo human ovaries. An assessment of the photoacoustic images has revealed light absorption distribution in the ovary, which is directly related to the vasculature distribution and amount. Quantification of the light absorption levels in the ovary has indicated that, in the postmenopausal group, malignant ovaries showed significantly higher light absorption than normal ones (P = .0237). For these two groups, we have obtained a sensitivity of 83% and a specificity of 83%. This result suggests that PAI is a promising modality for improving ultrasound diagnosis of ovarian cancer.

Present and future of FDG-PET/CT in ovarian cancer

Integrated FDG-PET/CT has been used successfully for the diagnosis, staging, restaging, therapy monitoring and prognostic prediction of ovarian cancer as well as various other malignant tumors. Compared with conventional PET/non-contrast CT images, combined PET/contrast-enhanced CT images with intravenous iodine contrast medium and sufficient radiation dose may contribute to a more accurate diagnosis with higher confidence. In the future, tracers other than FDG and integrated PET/MRI will be realized. We herein review the place and role of FDG-PET/CT in the management of ovarian cancer, discussing its usefulness and limitations in the imaging of these patients.

Clinical utility of positron emission tomography/computed tomography in the evaluation of suspected recurrent ovarian cancer in the setting of normal CA-125 levels

OBJECTIVES

This study was conducted to estimate the accuracy of [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) as compared with contrast-enhanced CT (CECT) in detecting cancer in patients who have normal cancer antigen (CA)-125 (<35 U/dL) but are suspected of having a recurrent disease based on clinical symptoms.

METHODS

We retrospectively reviewed the records of patients who had undergone primary cytoreductive surgery and subsequently underwent CECT and FDG-PET/CT for suspected recurrence. [18F]-fluorodeoxyglucose positron emission tomography/computed tomography and CECT interpretation to evaluate a recurrent disease was carried out independently by 2 experienced radiologists who were blinded to the final diagnosis for the suspected recurrence. Long-term follow-up imaging (12 months) and biopsy reports were used to assess the true status of the suspected recurrence seen on FDG-PET/CT or CECT. Sensitivity and specificity of all modalities were estimated. McNemar test was used to compare pairs of modalities. All tests were 2-sided, and P < or = 0.05 was considered statistically significant.

RESULTS

Sixty-six patients met the eligibility criteria for inclusion in our analysis. Fifty-eight percent (18/31) and 54% (17/31) of the patients with normal CA-125 levels had evidence of a recurrent disease on FDG-PET/CT and CECT, respectively. Thirty-one percent (6/19) of the patients with no indication of cancer on CECT had evidence of disease on FDG-PET/CT images, which was supported by pathological proof.

CONCLUSION

[18F]-Fluorodeoxyglucose positron emission tomography/computed tomography is capable of detecting ovarian cancer recurrence in symptomatic patients with normal CA-125 levels and, in this setting, has slightly better sensitivity than CECT and can be considered as the frontline modality for all such patients.

The Roles of Fluorodeoxyglucose-PET/Computed Tomography in Ovarian Cancer: Diagnosis, Assessing Response, and Detecting Recurrence

The potential roles of fluorodeoxyglucose positron emission tomography/computed tomography imaging in ovarian cancer include noninvasive characterization of an ovarian mass, staging, and treatment planning. This article assesses these roles for predicting and monitoring response to treatment, restaging, and early diagnosis of recurrence.

Recurrent ovarian cancer: use of contrast-enhanced CT and PET/CT to accurately localize tumor recurrence and to predict patients' survival

PURPOSE

To compare accuracy and interobserver variability in the detection and localization of recurrent ovarian cancer with contrast material-enhanced (CE) computed tomography (CT) and positron emission tomography (PET)/CT and determine whether imaging findings can be used to predict survival.

MATERIALS AND METHODS

Waiving informed consent, the institutional review board approved this HIPAA-compliant, retrospective study of 35 women (median age, 54.4 years) with histopathologically proven recurrent ovarian carcinoma who underwent CE CT and PET/CT before exploratory surgery. All CE CT and PET/CT scans were independently analyzed. Tumor presence, number of lesions, and the size and maximum standardized uptake value (SUV(max)) of the largest lesion were recorded for patient and region. Surgical histopathologic findings constituted the reference standard. Areas under the receiver operating characteristic curves (AUCs), κ statistics, and hazard ratios were calculated.

RESULTS

Readers' AUCs in detection of recurrence for region were 0.85 (95% confidence interval [CI]: 0.81, 0.90) and 0.78 (95% CI: 0.72, 0.83) for CE CT and 0.84 (95% CI: 0.79, 0.89) and 0.74 (95% CI: 0.67, 0.81) for PET/CT (P = .76); 12 patients died. At PET/CT, size, number, and SUV(max) of peritoneal deposits were significantly associated with poor survival for readers 1 and 2 (P ≤ .01and ≤ .05, respectively), as were long- and short-axis diameters, number, and SUV(max) of distant lymph nodes for reader 1 (P ≤ .001). With CE CT, size (reader 1) and number (readers 1 and 3) of peritoneal deposits were significantly associated with poor survival (P ≤ .01), as were long- and short-axis diameters and number of distant lymph nodes for reader 1 (P ≤ .01). Interobserver agreement ranged from fair (patient, κ = 0.30) to moderate (region, κ = 0.55) for CE CT and fair (patient, κ = 0.24) to substantial (region, κ = 0.63) for PET/CT.

CONCLUSION

Preliminary data suggest that CE CT and PET/CT may have similar accuracy in detection of recurrent ovarian cancer. Tumor size, number, and SUV(max) may have potential as prognostic biomarkers for patients with recurrent ovarian cancer.

Present and future of PET and PET/CT in gynaecologic malignancies

OBJECTIVES

To review the published data in literature on patients affected by gynaecological malignancies to establish the role of (18)F-FDG positron emission tomography (PET) and PET/CT in comparison to conventional imaging (CI).

MATERIALS AND METHODS

All papers specifically addressed to the role of (18)F-FDG PET and PET/CT in gynaecological malignancies published on PubMed/Medline, in abstracts from the principal international congresses, in the guidelines from national Societies that had appeared in literature until November 2009 were considered for the purpose of the present study.

RESULTS AND CONCLUSIONS

The use of (18)F-FDG PET, and even more of (18)F-FDG PET/CT, is increasing in the follow up of patients with gynaecologic malignancies and suspected recurrent disease: there is evidence in the literature that (18)F-FDG PET/CT has a higher sensitivity than CI in depicting occult metastatic spread. An interesting issue is represented by patients with ovarian cancer with an increase of the specific biomarker, CA-125, and negative/inconclusive findings at CI. The use of (18)F-FDG PET in differential diagnosis and staging is more controversial, but there is some evidence that a baseline PET examination performed before commencing therapy, for staging purpose, is also useful to evaluate the response to chemoradiation treatment. In several papers it has been suggested a relevant role of (18)F-FDG PET/CT in evaluating the entity of response to treatment and therefore to plan the subsequent therapeutic strategy.