Imaging in the pre-operative staging of ovarian cancer

Nuclear Medicine and Molecular Imaging Applications in Gynecologic Malignancies: A Comprehensive Review

Gynecologic malignancies, consisting of endometrial, cervical, ovarian, vulvar, and vaginal cancers, pose significant diagnostic and management challenges due to their complex anatomic location and potential for rapid progression. These tumors cause substantial morbidity and mortality, often because of their delayed diagnosis and treatment. An estimated 19% of newly diagnosed cancers among women are gynecologic in origin. In recent years, there has been growing evidence supporting the integration of nuclear medicine imaging modalities in the diagnostic work-up and management of gynecologic cancers. The sensitivity of fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) combined with the anatomical specificity of computed tomography (CT) and magnetic resonance imaging (MRI) allows for the hybrid evaluation of metabolic activity and structural abnormalities that has become an indispensable tool in oncologic imaging. Lymphoscintigraphy, using technetium 99m (99mTc) based radiotracers along with single photon emission computed tomography/ computed tomography (SPECT/CT), holds a vital role in the identification of sentinel lymph nodes to minimize the surgical morbidity from extensive lymph node dissections. While not yet standard for gynecologic malignancies, promising therapeutic nuclear medicine agents serve as specialized treatment options for patients with advanced or recurrent disease. This article aims to provide a comprehensive review on the nuclear medicine applications in gynecologic malignancies through the following objectives: 1) To describe the role of nuclear medicine in the initial staging, lymph node mapping, response assessment, and recurrence/surveillance imaging of common gynecologic cancers, 2) To review the limitations of 18F-FDG PET/CT and promising applications of 18F-FDG PET/MRI in gynecologic malignancy, 3) To underscore the promising theragnostic applications of nuclear medicine, 4) To highlight the current role of nuclear medicine imaging in gynecologic cancers as per the National Comprehensive Cancer Network (NCCN), European Society of Surgical Oncology (ESGO), and European Society of Medical Oncology (ESMO) guidelines.

Gynecologic oncology tumor board: the central role of the radiologist

This manuscript is a collaborative, multi-institutional effort by members of the Society of Abdominal Radiology Uterine and Ovarian Cancer Disease Focus Panel and the European Society of Urogenital Radiology Women Pelvic Imaging working group. The manuscript reviews the key role radiologists play at tumor board and highlights key imaging findings that guide management decisions in patients with the most common gynecologic malignancies including ovarian cancer, cervical cancer, and endometrial cancer.

Unresectable Ovarian Cancer Requires a Structured Plan of Action: A Prospective Cohort Study

BACKGROUND

Patients with unresectable disease during cytoreductive surgery (CRS) for advanced-stage ovarian cancer are underreported. Knowledge of treatment and survival after surgery is limited. The aim of this study is to address the knowledge gap about postoperative treatment and survival of patients whose surgery was abandoned due to unresectability after abdominal exploration.

METHODS

Women with FIGO stage IIIB-IV epithelial ovarian cancer whose disease was considered to be unresectable during surgery were included in this prospective study, a post hoc analysis of the PlaComOv study. The unresectable disease was defined as the inability to achieve at least suboptimal CRS without attempted CRS after careful inspection of the entire abdomen. Preoperative clinical data, perioperative findings, postoperative treatment and survival data were analyzed.

RESULTS

From 2018 to 2020, 27 patients were included in this analysis. Treatment ranged from the cessation of treatment to one or several lines of chemotherapy with or without maintenance therapy. The median overall survival was 16 (IQR 5-21) months (95%CI 14-18). At 24 months of follow-up, four patients (15%) were alive.

CONCLUSIONS

This study indicated a two-year survival of 15%. Optimal treatment strategies in terms of survival benefits are still ill-defined. Further study of this specific group of patients is warranted. We advocate an (inter)national registry of patients with unresectable cancer and comprehensive follow-up.

A practical spatial analysis method for elucidating the biological mechanisms of cancers with abdominal dissemination in vivo

Elucidation of spatial interactions between cancer and host cells is important for the development of new therapies against disseminated cancers. The aim of this study is to establish easy and useful method for elucidating spatial interactions. In this study, we developed a practical spatial analysis method using a gel-based embedding system and applied it to a murine model of cancer dissemination. After euthanization, every abdominal organ enclosed in the peritoneum was extracted en bloc. We injected agarose gel into the peritoneal cavities to preserve the spatial locations of the organs, including their metastatic niches, and then produced specimens when the gel had solidified. Preservation of the original spatial localization was confirmed by correlating magnetic resonance imaging results with the sectioned specimens. We examined the effects of spatial localization on cancer hypoxia using immunohistochemical hypoxia markers. Finally, we identified the mRNA expression of the specimens and demonstrated the applicability of spatial genetic analysis. In conclusion, we established a practical method for the in vivo investigation of spatial location-specific biological mechanisms in disseminated cancers. Our method can elucidate dissemination mechanisms, find therapeutic targets, and evaluate cancer therapeutic effects.

Habitat radiomics analysis of pet/ct imaging in high-grade serous ovarian cancer: Application to Ki-67 status and progression-free survival

Purpose: We aim to develop and validate PET/ CT image-based radiomics to determine the Ki-67 status of high-grade serous ovarian cancer (HGSOC), in which we use the metabolic subregion evolution to improve the prediction ability of the model. At the same time, the stratified effect of the radiomics model on the progression-free survival rate of ovarian cancer patients was illustrated.

Materials and methods: We retrospectively reviewed 161 patients with HGSOC from April 2013 to January 2019. 18F-FDG PET/ CT images before treatment, pathological reports, and follow-up data were analyzed. A randomized grouping method was used to divide ovarian cancer patients into a training group and validation group. PET/ CT images were fused to extract radiomics features of the whole tumor region and radiomics features based on the Habitat method. The feature is dimensionality reduced, and meaningful features are screened to form a signature for predicting the Ki-67 status of ovarian cancer. Meanwhile, survival analysis was conducted to explore the hierarchical guidance significance of radiomics in the prognosis of patients with ovarian cancer.

Results: Compared with texture features extracted from the whole tumor, the texture features generated by the Habitat method can better predict the Ki-67 state (p < 0.001). Radiomics based on Habitat can predict the Ki-67 expression accurately and has the potential to become a new marker instead of Ki-67. At the same time, the Habitat model can better stratify the prognosis (p < 0.05).

Conclusion: We found a noninvasive imaging predictor that could guide the stratification of prognosis in ovarian cancer patients, which is related to the expression of Ki-67 in tumor tissues. This method is of great significance for the diagnosis and treatment of ovarian cancer.

Ovarian cancer reporting lexicon for computed tomography (CT) and magnetic resonance (MR) imaging developed by the SAR Uterine and Ovarian Cancer Disease-Focused Panel and the ESUR Female Pelvic Imaging Working Group

OBJECTIVES

Imaging evaluation is an essential part of treatment planning for patients with ovarian cancer. Variation in the terminology used for describing ovarian cancer on computed tomography (CT) and magnetic resonance (MR) imaging can lead to ambiguity and inconsistency in clinical radiology reports. The aim of this collaborative project between Society of Abdominal Radiology (SAR) Uterine and Ovarian Cancer (UOC) Disease-focused Panel (DFP) and the European Society of Uroradiology (ESUR) Female Pelvic Imaging (FPI) Working Group was to develop an ovarian cancer reporting lexicon for CT and MR imaging.

METHODS

Twenty-one members of the SAR UOC DFP and ESUR FPI working group, one radiology clinical fellow, and two gynecologic oncology surgeons formed the Ovarian Cancer Reporting Lexicon Committee. Two attending radiologist members of the committee prepared a preliminary list of imaging terms that was sent as an online survey to 173 radiologists and gynecologic oncologic physicians, of whom 67 responded to the survey. The committee reviewed these responses to create a final consensus list of lexicon terms.

RESULTS

An ovarian cancer reporting lexicon was created for CT and MR Imaging. This consensus-based lexicon has 6 major categories of terms: general, adnexal lesion-specific, peritoneal carcinomatosis-specific, lymph node-specific, metastatic disease -specific, and fluid-specific.

CONCLUSIONS

This lexicon for CT and MR imaging evaluation of ovarian cancer patients has the capacity to improve the clarity and consistency of reporting disease sites seen on imaging.

KEY POINTS

• This reporting lexicon for CT and MR imaging provides a list of consensus-based, standardized terms and definitions for reporting sites of ovarian cancer on imaging at initial diagnosis or follow-up. • Use of standardized terms and morphologic imaging descriptors can help improve interdisciplinary communication of disease extent and facilitate optimal patient management. • The radiologists should identify and communicate areas of disease, including difficult to resect or potentially unresectable disease that may limit the ability to achieve optimal resection.

Past, Present, and Future of Serum Tumor Markers in Management of Ovarian Cancer: A Guide for the Radiologist

The ability to accurately detect early ovarian cancer and subsequently monitor treatment response is essential to improving survival for patients with ovarian malignancies. Several serum tumor markers (STMs)-including cancer antigen 125 (CA-125), human epididymis protein 4 (HE4), cancer antigen 19-9 (CA 19-9), and carcinoembryonic antigen (CEA)-have been used as a noninvasive method of identifying ovarian cancer in conjunction with imaging. Although current guidelines do not recommend use of STMs as screening tools for ovarian cancer, these markers have clinical utility in both diagnosis and surveillance for women with ovarian cancer. CA-125 is the most commonly used STM; its level may be elevated in several types of ovarian cancer, including epithelial cell tumors, carcinosarcoma, teratomas, and secondary ovarian malignancies. An elevated level of CA 19-9 is associated with clear cell tumors, teratomas, and secondary malignancies. CEA is most commonly associated with mucinous ovarian cancers. Finally, HE4 is being increasingly used to identify certain subtypes of epithelial ovarian cancers, particularly serous and endometrioid tumors. Diagnosis of ovarian cancers relies on a combination of CA-125 levels and US findings, which include a large adnexal mass or high-risk features, including septa and increased vascularity. CT is preferred for staging and is used along with PET and STM monitoring for surveillance. Increasingly, MRI is being used to characterize ovarian lesions that are indeterminate at US or CT. The future of STM testing involves development of "liquid biopsies," in which plasma samples are analyzed for evidence of tumors, including circulating tumor DNA or tumor cells and tumor micro-RNA. When combined with traditional imaging techniques, liquid biopsies may lead to earlier diagnosis and improved survival. An invited commentary by Shinagare is available online. ^©RSNA, 2021.

Preoperative LMR and Serum CA125 Level as Risk Factors for Advanced Stage of Ovarian Cancer

Objectives: This study was to analyze the relationships between lymphocyte-to-monocyte ratio (LMR) alone or combined with serum CA125 (COLC) and advanced stage of ovarian cancer (OC).

Methods: The receiver-operating characteristic (ROC) curves of LMR, CA125, and COLC staging OC were constructed by a retrospective study. Furthermore, a binary logistic regression model was used to assay the independent risk factors for OC staging.

Results: Two hundred and twenty-five patients with OC were identified in this cohort. Eighty-five OC patients were diagnosed at an early stage, and 140 OC patients were diagnosed at an advanced stage. The median of LMR in the early stage was higher than that in advanced stage (4.4 vs. 2.8), and the median of serum CA125 was lower than that in advanced stage (80 U/mL vs. 251.3 U/mL). Multivariate logistic regression LMR≤3.7 (OR=0.299, 95% CI: 0.093-0.962, P=0.043) and CA125>95.7 U/mL (OR=4.317, 95% CI: 1.436-12.977, P=0.009) were risk factors for stage of advanced OC whether presence or absence of malignant ascites. Furthermore, the area under the curve of COLC was higher than that of LMR (0.782 vs. 0.732) or serum CA125 (0.782 vs. 0.708) in staging OC. The specificity of COLC was higher than that of LMR (87.1% vs. 70.6%) or serum CA125 (87.1% vs. 61.2%) in staging OC.

Conclusion: LMR alone or in combination with serum CA125 might be associated with OC staging. Besides, as a predictive factor, COLC may have a high specificity in staging OC.

Relative clinical utility of simultaneous 18F-fluorodeoxyglucose PET/MRI and PET/CT for preoperative cervical cancer diagnosis

Objective

To investigate the utility of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) for the preoperative diagnosis of cervical cancer.

Methods

We retrospectively analyzed 114 patients who were diagnosed with cervical cancer and underwent PET/MRI (n = 59) or PET/computed tomography (PET/CT) (n = 65) before surgery. The maximal standardized uptake value (SUV_max) and mean SUV (SUV_mean) were determined for regions of interest in the resultant radiographic images.

Results

Relative to PET/CT, ¹⁸F-FDG PET/MRI exhibited higher specificity and sensitivity in defining the primary tumor bounds and higher sensitivity for detection of bladder involvement. The SUV_max and SUV_mean of PET/MRI were remarkably higher than those of PET/CT as a means of detecting primary tumors, bladder involvement, and the lymph node status. However, no significant differences in these values were detected when comparing the two imaging approaches as a means of detecting vaginal involvement or para-aortic lymph node metastasis.

Conclusions

These outcomes may demonstrate the capability of ¹⁸F-FDG PET/MRI to clarify preoperative cervical cancer diagnoses in the context of unclear PET/CT findings. However, studies directly comparing SUVs in different lesion types from patients who have undergone both PET/MRI and PET/CT scans are essential to validate and expand upon these findings.

MDCT evaluation of synchronous breast carcinoma and other solid malignancies

BACKGROUND

Multiple primary malignancies are two or more malignancies in an individual without any relationship between the tumors. The development of improved diagnostic techniques, increased survival of cancer patients and the growing life expectancy have all contributed to the increased frequency of this phenomenon.

OBJECTIVE

The aim of this study is to review the multidetector computed tomography (MDCT) findings of synchronous breast carcinoma and other solid malignancies.

METHODS

This retrospective study included 65 patients confirmed with diagnosis of synchronous breast carcinoma and other solid malignancies. CT scanning was performed using 128 MDCT in all patients. All one hundred-thirty malignancies underwent pathological evaluation.

RESULTS

Out of 4120 patients with breast carcinoma; 65 patients were diagnosed with other synchronous primary solid malignancy. All one hundred-thirty malignancies were confirmed pathologically. Breast carcinoma detected in all 65 patients; of them metastatic breast carcinoma detected in 8 patients. Hepatocellular carcinoma was detected in 18 patients, Non-Hodgkin lymphoma (NHL) in 12 patients, endometrial carcinoma in 8 patients, uterine sarcoma in 3 patients, malignant mixed Müllerian tumor in one patient, ovarian carcinoma in 5 patients, renal cell carcinoma in 4 patients, thyroid carcinoma in 4 patients, gastric carcinoma in 2 patients, colonic carcinoma in 2 patients, ano-rectal carcinoma in one patient, hilar cholangiocarcinoma in 2 patients, malignant melanoma in 2 patients and bronchogenic carcinoma in one patient.

CONCLUSIONS

Patients with breast carcinoma have a risk of other synchronous primary malignancy. So, careful preoperative examination is recommended to improve the patients' prognosis. MDCT scanning is accurately imaging modality for evaluation of synchronous breast carcinoma and other solid malignancies. The aim of treatment in cancer patients should always be curative even in the presence of multiple malignancies.

Current update on malignant epithelial ovarian tumors

Epithelial ovarian cancer (EOC) represents the most frequently occurring gynecological malignancy, accounting for more than 70% of ovarian cancer deaths. Preoperative imaging plays an important role in assessing the extent of disease and guides the next step in surgical decision-making and operative planning. In this article, we will review the multimodality imaging features of various subtypes of EOC. We will also discuss the role of imaging in the staging, management, and surveillance of EOC.

Assessment of peritoneal metastases with DW-MRI, CT, and FDG PET/CT before cytoreductive surgery for advanced stage epithelial ovarian cancer

BACKGROUND

Preoperative assessment of peritoneal metastases is an important factor for treatment planning and selection of candidates for cytoreductive surgery (CRS) in primary advanced stage (FIGO stages III-IV) epithelial ovarian cancer (EOC). The primary aim was to evaluate the efficacy of DW-MRI, CT, and FDG PET/CT used for preoperative assessment of peritoneal cancer index (PCI).

MATERIAL AND METHODS

In this prospective observational cohort study, 50 advanced stage EOC patients were examined with DW-MRI and FDG PET/CT with contrast enhanced CT as part of the diagnostic program. All patients were deemed amenable for upfront CRS. Imaging PCI was determined for DW-MRI, CT, and FDG PET/CT by separate readers blinded to the surgical findings. The primary outcome was agreement between the imaging PCI and PCI determined at surgical exploration (the reference standard) evaluated with Bland-Altman statistics.

RESULTS

The median surgical PCI was 18 (range: 3-32). For all three imaging modalities, the imaging PCI most often underestimated the surgical PCI. The mean differences between the surgical PCI and the imaging PCI were 4.2 (95% CI: 2.6-5.8) for CT, 4.4 (95% CI: 2.9-5.8) for DW-MRI, and 5.3 (95% CI: 3.6-7.0) for FDG PET/CT, and no overall statistically significant differences were found between the imaging modalities (DW-MRI - CT, p = 0.83; DW-MRI - FDG PET/CT, p = 0.24; CT - FDG PET/CT, p = 0.06).

CONCLUSION

Neither DW-MRI nor CT nor FDG PET/CT was superior in preoperative assessment of the surgical PCI in patients scheduled for upfront CRS for advanced stage EOC.

Management Driven Structured Reporting in Ovarian Cancer

Since majority (80%) of ovarian cancer patients present at an advanced stage, imaging performed on these patients have numerous findings. The combination of multiple findings on imaging, complexity of anatomical structures which are involved in ovarian cancer, and the need to perceive certain subtle imaging features which would impact management often makes it challenging to systematically review images of these patients. Similarly, it is difficult to effectively communicate these findings in radiology reports. Structured reporting that is geared toward clinical decision-making has been an area of recognized need. An understanding of the review areas, which aid clinical decision-making in a multidisciplinary team setting at our institution led us to the proposed structured reporting template for ovarian cancer. Through this review, the authors would like to share this reporting template with examples.

Adnexal incidentalomas on multidetector CT: how to manage and characterise

Although CT is not considered the examination of choice for the detection and characterisation of adnexal diseases, adnexal masses may be incidentally detected during CT examination performed for other clinical indications. Most adnexal incidentalomas are benign, and therefore may not require further investigation, follow-up or intervention; however, few of them may prove malignant. Multidetector CT has improved the diagnostic performance of the technique in the detection and differentiation of adnexal mass lesions. Radiologists should be able to recognise the normal CT appearance of the ovaries and the CT characteristics of various adnexal incidentalomas. This may obviate unnecessary imaging evaluation and allow optimal treatment planning. Regarding the management of adnexal lesions incidentally found on CT, recommendations based on the collective experience of the members of the American College of Radiology Incidental Findings Committee II have recently been presented.