The role of FDG-PET/CT in gynaecological cancers

Incidental endometrial cancer detected on FDG PET/CT imaging for melanoma

This case report follows a 66-year-old female who originally presented with malignant melanoma in the left knee and recurrence in the left inguinal region. This prompted a whole body FDG PET/CT scan which showed incidental focal hypermetabolism in the uterus. The diagnosis of endometrial cancer was confirmed at biopsy, and the patient was treated with total abdominal hysterectomy. Melanoma patients are at increased risk of second primary malignancy, and endometrial cancer is a common second primary often diagnosed in cancer survivors. Incidental endometrial focal hypermetabolism should be investigated further for a synchronous malignancy, especially in a post-menopausal woman.

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.

Changing Role of PET/CT in Cancer Care With a Focus on Radiotherapy

Positron emission tomography (PET) integrated with computed tomography (CT) has brought revolutionary changes in improving cancer care (CC) for patients. These include improved detection of previously unrecognizable disease, ability to identify oligometastatic status enabling more aggressive treatment strategies when the disease burden is lower, its use in better defining treatment targets in radiotherapy (RT), ability to monitor treatment responses early and thus improve the ability for early interventions of non-responding tumors, and as a prognosticating tool as well as outcome predicting tool. PET/CT has enabled the emergence of new concepts such as radiobiotherapy (RBT), radioimmunotherapy, theranostics, and pharmaco-radiotherapy. This is a rapidly evolving field, and this primer is to help summarize the current status and to give an impetus to developing new ideas, clinical trials, and CC outcome improvements.

Evaluation of a CD13 and Integrin αvβ3 Dual-Receptor Targeted Tracer 68Ga-NGR-RGD for Ovarian Tumor Imaging: Comparison With 18F-FDG

Ovarian cancer has the highest mortality rate of gynecologic malignancy. ¹⁸F-FDG positron emission tomography (PET) adds an important superiority over traditional anatomic imaging modalities in oncological imaging but has drawbacks including false negative results at the early stage of ovarian cancer, and false positives when inflammatory comorbidities are present. Aminopeptidase N (APN, also known as CD13) and integrin α_vβ₃ are two important targets overexpressed on tumor neo-vessels and frequently on ovarian cancerous cells. In this study, we used subcutaneous and metastatic models of ovarian cancer and muscular inflammation models to identify ⁶⁸Ga-NGR-RGD, a heterodimeric tracer consisting of NGR and RGD peptides targeting CD13 and integrin α_vβ₃, respectively, and compared it with ¹⁸F-FDG. We found that ⁶⁸Ga-NGR-RGD showed greater contrast in SKOV3 and ES-2 tumors than ¹⁸F-FDG. Low accumulation of ⁶⁸Ga-NGR-RGD but avid uptake of ¹⁸F-FDG were observed in inflammatory muscle. In abdominal metastasis models, PET imaging with ⁶⁸Ga-NGR-RGD allowed for rapid and clear delineation of both peritoneal and liver metastases (3-6 mm), whereas, ¹⁸F-FDG could not distinguish the metastasis lesions due to the relatively low metabolic activity in tumors and the interference of intestinal physiological ¹⁸F-FDG uptake. Due to the high tumor-targeting efficacy, low inflammatory uptake, and higher tumor-to-background ratios compared to that of ¹⁸F-FDG, ⁶⁸Ga-NGR-RGD presents a promising imaging agent for diagnosis, staging, and follow-up of ovarian tumors.

Characteristics of surgically transposed ovaries on 18F-FDG PET/CT among patients with cancer

OBJECTIVE

Fertility preservation in women with cancer is important for improving their quality of life. Successful ovarian transposition protects the ovary from radiation and preserves ovarian endocrine function and fertility. With the increasing use of 18F-FDG PET/CT in gynecologic malignancies, the findings of transposed ovaries sometimes vary. This study aimed to characterize the 18F-FDG PET/CT findings of surgically transposed ovaries among a large number of patients with various medical conditions.

METHODS

We retrospectively reviewed the medical records, including surgical history, and analyzed the findings of the transposed ovaries of patients who underwent ovarian transposition. Quantitative analysis was performed, and the maximum standardized uptake values (SUVs) were recorded. The Hounsfield unit (HU) and size (measured using the long diameter on the axial image) of the transposed ovary were evaluated.

RESULTS

No significant change was found in the SUV of the transposed ovaries in relation to age and time after surgery. In two cases in which metastasis occurred in the transposed ovary, the lesions showed higher SUVs and HUs than did the other non-metastatic transposed ovaries. In several serial follow-up cases, varying 18F-FDG uptake was observed.

CONCLUSION

The 18F-FDG uptake pattern of the transposed ovary did not differ from that of the normal ovary. Misinterpretation should be avoided by considering surgical records, presence of surgical clips, and patients' disease state. If there is a high uptake in the transposed ovary, it is necessary to check for soft tissue lesions and differentiate metastasis from the physiologic uptake.

18F-FDG PET/CT in ovarian cancer recurrence: Clinical impact, correlation with ceCT and CA-125, and prognostic value

AIM

To evaluate ¹⁸F-FDG-PET/CT for suspected ovarian cancer relapse with negative/inconclusive conventional imaging, or restaging potentially resectable ovarian cancer relapse.

MATERIAL AND METHODS

Thirty-six cases and 140 locations were studied. PET/CT, ceCT and serum CA-125 was conducted in all cases. Nineteen cases were requested for restaging, 17 for suspected relapse. We compared ceCT and PET/CT, assessed by histopathology or radiological follow-up, calculating sensitivity (S) and positive predictive value (PPV) by cases and lesions. We evaluated the correlation between size, number, uptake of the lesions and CA-125. We conducted survival analysis, using ROC curves to calculate the optimal cut-off of SUVmax for survival prediction. We checked whether PET/CT modify the therapeutic attitude vs. conventional imaging.

RESULTS

PET/CT and ceCT were concordant in 12 cases: 11 positives (30 lesions), all confirmed. There was 1 FN. In the 24 non-concordant, PET/CT was positive in 19 (97 lesions); ceCT in 21 (59 lesions); 54% of the lesions were concordant. Overall, PET/CT detected 127 lesions, with S = 97% and PPV = 100%. ceCT detected 89 lesions, with S = 61% and PPV = 90%. No significant correlation was found between CA-125 and the other parameters. PET/CT detected 10 positive cases, with normal CA-125. PET/CT modified therapeutic management in 15 cases. Significant differences were found in survival with SUVmax = 11.8 CONCLUSIONS: PET/CT plays an important role in ovarian cancer relapse, with sensitivity and PPV higher than ceCT, modified therapeutic management in up to 42% of cases, and could be a valuable tool for predicting survival.

The prognostic value of 18F-fluorodeoxyglucose positron emission tomography/ computed tomography parameters in patients with malignant pleural mesothelioma

Background

In this study, we aimed to investigate the prognostic value of metabolic ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography parameters in malignant pleural mesothelioma patients.

Methods

A total of 65 patients with malignant pleural mesothelioma (34 males, 31 females; median age: 60 years; range, 39 to 84 years) who underwent whole-body ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography for staging before treatment between March 2008 and January 2018 were included. Relationships between clinicopathological factors and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography parameters and overall survival were evaluated using a log-rank test and Cox regression analysis.

Results

The median follow-up was 13 (range, 4 to 55) months. The Kaplan-Meier analysis revealed a mean survival time of 17±2.6 months. The cumulative two- and five-year survival rates were 34.8% and 7.8%, respectively. Univariate analysis showed that ≥60 age, left hemithorax involvement, a maximum standardized uptake value of ≥9.8, c-T4 status, c-M1 status, and non-surgery were negatively associated with overall survival (p<0.05). Multivariate analysis showed that ≥60 age, left hemithorax involvement, a maximum standardized uptake value of ≥9.8, c-M1 status, and a total lesion glycolysis of ≥180.2 g were negatively associated with overall survival (p<0.05).

Conclusion

Metabolic parameters of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography have the potential to provide prognostic information for malignant pleural mesothelioma patients who are receiving surgery and/or chemotherapy.

18F-FDG PET/CT in ovarian cancer recurrence: Clinical impact, correlation with ceCT and CA-125, and prognostic value

AIM

To evaluate ¹⁸F-FDG-PET/CT for suspected ovarian cancer relapse with negative/inconclusive conventional imaging, or restaging potentially resectable ovarian cancer relapse.

MATERIAL AND METHODS

Thirty-six cases and 140 locations were studied. PET/CT, ceCT and serum CA-125 was conducted in all cases. Nineteen cases were requested for restaging, 17 for suspected relapse. We compared ceCT and PET/CT, assessed by histopathology or radiological follow-up, calculating sensitivity (S) and positive predictive value (PPV) by cases and lesions. We evaluated the correlation between size, number, uptake of the lesions and CA-125. We conducted survival analysis, using ROC curves to calculate the optimal cut-off of SUVmax for survival prediction. We checked whether PET/CT modify the therapeutic attitude vs. conventional imaging.

RESULTS

PET/CT and ceCT were concordant in 12 cases: 11 positives (30 lesions), all confirmed. There was 1 FN. In the 24 non-concordant, PET/CT was positive in 19 (97 lesions); ceCT in 21 (59 lesions); 54% of the lesions were concordant. Overall, PET/CT detected 127 lesions, with S=97% and PPV=100%. ceCT detected 89 lesions, with S=61% and PPV=90%. No significant correlation was found between CA-125 and the other parameters. PET/CT detected 10 positive cases, with normal CA-125. PET/CT modified therapeutic management in 15 cases. Significant differences were found in survival with SUVmax=11.8 CONCLUSIONS: PET/CT plays an important role in ovarian cancer relapse, with sensitivity and PPV higher than ceCT, modified therapeutic management in up to 42% of cases, and could be a valuable tool for predicting survival.

Fluorodeoxyglucose positron-emission tomography-magnetic resonance hybrid imaging: An emerging tool for staging of cancer of the uterine cervix

Positron-emission tomography-magnetic resonance imaging (PET-MRI) is an emerging hybrid imaging modality that utilizes the superior soft tissue resolution of MR with the metabolic data from PET. In this study, we sought to assess the clinical value of fluorodeoxyglucose (FDG) PET-MRI with dedicated pelvic PET-MR in the initial staging of cervical cancer. In this institutional-approved study, we identified 23 adult females who underwent FDG PET-MRI on hybrid camera for staging of primary uterine cervical cancer that included a dedicated PET-MR of the pelvis. A nuclear medicine physician and a radiologist reviewed the PET, MRI, and fusion-body and pelvis images alone and then with consensus read characterizing PET and MR abnormal findings. There were 23 patients who underwent FDG PET-MRI for initial staging of cervical cancer with an average age of 52.2 ± 14.0 years. A total of 23 suspected lymph nodes in eight different patients were detected within the pelvis with increased metabolic activity on PET. Both the dedicated pelvis and whole-body PET imaging detected the same corresponding pelvic lymph nodes, although the pelvic PET imaging had better lymph node uptake delineation due to longer acquisition time. Using a 10-mm short-axis criterion, MRI identified only 43.5% of the FDG avid lymph nodes. The average SUVmax on the pelvis PET sequences was higher with SUV 8.9 ± 5.2 compared to the whole-body PET with SUV 7.8 ± 5.4 but was not statistically significant (P > 0.05). Primary cervical cancer was identified in 18 patients on both PET imaging and MRI with dedicated MR pelvis providing better characterization. Based on our results of the patients with cervical cancer evaluated for initial staging, combining dedicated pelvic PET-MRI with whole-body PET/MR provides the most complete status of malignant disease in reference to delineation of primary tumor, involvement of surrounding tissues, and regional lymph nodes.

The Role of Hyperglycemia in Endometrial Cancer Pathogenesis

Endometrial cancer is one of the most common cancers in women worldwide and its incidence is increasing. Epidemiological evidence shows a strong association between endometrial cancer and obesity, and multiple mechanisms linking obesity and cancer progression have been described. However, it remains unclear which factors are the main drivers of endometrial cancer development. Hyperglycemia and type 2 diabetes mellitus are common co-morbidities of obesity, and there is evidence that hyperglycemia is a risk factor for endometrial cancer independent of obesity. This review aims to explore the association between hyperglycemia and endometrial cancer, and discuss the evidence supporting a role for increased glucose metabolism in endometrial cancer and how this phenotype may contribute to endometrial cancer growth and progression. Finally, the potential role of blood glucose lowering strategies, including drugs and bariatric surgery, for the treatment of this malignancy will be discussed.

Clinical Impact of 18F-FDG PET/CT on the Management of Gynecologic Cancers: One Center Experience

Objective(s):

We aim to investigate the clinical impact of ¹⁸F-FDG PET/CT in managing patients with gynecological malignancies and pelvic or extrapelvic lymph nodes that are of equivocal significance on conventional imaging.

Methods:

We retrospectively evaluated ¹⁸F-FDG PET/CT scans of patients with gynecologic tumors who were referred to King Hussein Cancer Center from January 2010 to August 2014. PET/CT results were compared with MRI and CT findings. We evaluated sensitivity and specificity of ¹⁸F-FDG PET/CT, its role in changing treatment plan and its positive predictive value (PPV) and negative predictive value (NPV).

Results:

Ninety seven patients (mean age: 49 years) underwent ¹⁸F-FDG/PET in the study period (40 cervical, 37 endometrial and 20 ovarian cancers). PET/CT scan provided additional information in 23 patients; upstaging 4.1% (4 patients; 3 true positive) and down staging in 19.5% (19 patients; 15 true negative). As a result, treatment strategy was changed from curative to palliative in three patients, and modification of radiation field or additional curative therapy was implemented following exclusion of distant metastasis in 11 patients. Mean follow up time for the whole cohort was 35 months (range 6 - 60 months). NPV of ¹⁸F-FDG PET/CT in detecting extrapelvic lymphadenopathy was 83.3%.

Conclusion:

¹⁸F-FDG PET/CT has high clinical impact in management of gynaecological cancers as it alters the treatment plan in a substantial number of patients who had equivocal findings on conventional imaging, as well as it offers excellent validity in lymph nodes staging.

The role of FDG-PET/CT in gynecologic imaging: an updated guide to interpretation and challenges

All women, during their lifetime, are at risk of developing some form of gynecologic malignancy. The role of FDG-PET/CT has become more established in the management of gynecologic malignancies in the last decade. In this article, we will review the role of FDG-PET/CT in endometrial, cervical, ovarian, and vaginal cancer, by highlighting its strengths and limitations. While the role in initial or pre-operative staging for FDG-PET/CT is controversial, it allows noninvasive detection of equivocal or distant metastases, may alter stage and prognosis, and can guide or help eliminate unnecessary interventions that may not be beneficial. FDG-PET/CT is a useful adjunct to traditional staging with MR and CT.

Non-18F-2-Fluoro-2-Deoxy-d-Glucose PET/Computed Tomography in Gynecologic Oncology: An Overview of Current Status and Future Potential

The current status and future potential targets of non-¹⁸F-2-fluoro-2-deoxy-d-glucose (FDG) PET/computed tomography (CT) in 3 major gynecologic malignancies are discussed. Estrogen receptor-based 16alpha-¹⁸F-fluoro-17beta-estradiol (¹⁸F-FES) PET/CT has been investigated in (a) Uterine malignancies (both endometrial and myometrial pathologies) and (b) ovarian carcinoma. For uterine tumors, FDG/FES standardized uptake value and/or uptake ratio showed a positive correlation with malignant transformation (ie, endometrial carcinoma and uterine sarcoma) and higher malignant grades, whereas higher ¹⁸F-FES uptake was documented in benign pathologies (ie, endometrial hyperplasia and leiomyoma). For epithelial ovarian carcinomas, ¹⁸F-FES PET/CT can predict the response to antiestrogen therapy in platinum-resistant cases.

Evaluating the Role of F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Scanning in the Staging of Patients With Stage IIIB Cervical Carcinoma and the Impact on Treatment Decisions

OBJECTIVE

FIGO (International Federation of Gynaecology and Obstetrics) staging is currently the most widely used clinical staging system for cervical cancer; however, this staging system has many shortcomings. One of these shortcomings is that lymph nodal status, specifically the para-aortic lymph nodal status, does not get taken into account. It is known that metabolic changes occur before changes are seen on anatomical imaging, and it is therefore possible to detect metastases earlier with the help of fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). We hypothesized that by including an FDG PET/CT study as part of the staging investigations in patients with invasive cervical cancer, pretreatment staging would improve and management would change in a significant proportion of patients.

METHODS/MATERIALS

Patients diagnosed with FIGO stage IIIB cervical cancer from September 2010 to December 2015 received an FDG PET/CT study as part of their staging workup. A whole-body FDG PET/CT was performed before initiation of treatment, and the results were interpreted by experienced nuclear medicine physicians and radiologists. We determined the percentage of patients in whom PET/CT changed the stage and/or altered management of the patient.

RESULTS

There were 95 patients diagnosed with stage IIIB cervix cancer during the study period who received an FDG PET/CT as part of their staging workup. Eighty-eight patients were included in the final sample. Positron emission tomography/CT affected the management of 40% of patients, with 19% requiring a change in the radiation field due to identification of para-aortic nodal involvement and 21% upstaged to stage IVB.

CONCLUSIONS

Fluorodeoxyglucose PET/CT is useful in assessing distant disease and evaluating nodal involvement in patients with invasive cervical cancer. Additional findings on the PET/CT that were missed by conventional imaging and clinical examination caused treatment change in a significant proportion of patients.

Surveillance Imaging in Patients With Endometrial Cancer in First Remission

OBJECTIVE

The clinical benefit of surveillance imaging in endometrial cancer remains undefined. This retrospective study was conducted to evaluate the positive predictive value (PPV) of surveillance imaging in endometrial cancer.

METHODS

A total of 128 patients in first remission after treatment for endometrial cancer (uterine papillary serous, clear cell, stage III endometroid) who had surveillance imaging were retrospectively identified. The surveillance period was defined from the time of first-negative scan after treatment to the time when treatment was started for recurrent disease. Reports of surveillance scans were reviewed for the presence or absence of findings. The primary outcome was PPV of surveillance imaging. Cost and radiation exposure from surveillance imaging were also evaluated.

RESULTS

A total of 128 patients had 707 surveillance scans (computed tomography, positron emission tomography-computed tomography with 2-deoxy-2-[¹⁸F]fluoro-d-glucose, magnetic resonance image, and bone scans). Median follow-up was 54 months (range: 9-173). Of all, 47 patients (37%) started therapy for recurrent endometrial cancer at the discretion of the treating physician. PPV of all surveillance imaging was 57.7%. Per patient, the mean number of surveillance scans was 5.6 (range: 2-21). The mean cost of imaging was $4200 (range: $1200-$18,700) and mean radiation exposure was 109.6mSV (range: 16-445mSv).

CONCLUSIONS

Surveillance imaging detected a significant number of recurrences in patients with high-risk endometrial cancer at a reasonable cost related to the overall risk. Well-designed prospective imaging trials are warranted to assess the clinical benefit of surveillance imaging.

FDG-PET/CT in the Postoperative Period: Utility, Expected Findings, Complications, and Pitfalls

FDG-PET/CT as a modality is increasingly used for detection of recurrence and for restaging in patients with clinical suspicion of malignancy, as well as in patients with elevated tumor markers. However, there are many pitfalls in the interpretation of these scans when the studies are performed after some treatment. Some of these are attributed to normal physiological distribution and are compounded when there are inflammatory changes occurring after surgery. The body's inherent response to the surgical insult results in this inflammation. In addition, there are also complications that can happen following surgery, causing increased FDG uptake. Despite various fallacies, FDG-PET/CT provides valuable information in evaluation of residual and recurrent malignant disease. In this article, we aim to describe some of these postsurgical changes secondary to inflammation, common surgical complications, and finally, the utility of FDG-PET/CT in these patients to detect recurrent disease, even in the background of postsurgical changes.

The Emerging Role of PET/MR Imaging in Gynecologic Cancers

This article summarizes recent advances in PET/MR imaging in gynecologic cancers and the emerging clinical value of PET/MR imaging in the management of the 3 most common gynecologic malignancies: cervical, endometrial, and ovarian cancers. PET/MR imaging offers superior soft tissue contrast, improved assessment of primary tumor involvement because of high-resolution multiplanar reformats, and functional MR techniques such as diffusion-weighted MR imaging and dynamic contrast-enhanced MR imaging. This article discusses the challenges, future directions, and technical advances of PET/MR imaging, and the emerging new multimodality, multiparametric imaging techniques for integrating morphologic, functional, and molecular imaging data.

PET/CT and MRI in the imaging assessment of cervical cancer

Imaging plays a central role in the evaluation of patients with cervical cancer and helps guide treatment decisions. The purpose of this pictorial review is to describe magnetic resonance (MR) imaging and positron emission tomography (PET)/computed tomography (CT) assessment of cervical cancer, including indications for imaging, important findings that may result in management change, as well as limitations of both modalities. The International Federation of Gynecology and Obstetrics cervical cancer staging system does not officially include imaging; however, the organization endorses the use of MR imaging and PET/CT in the management of patients with cervical cancer where these modalities are available. MR imaging provides the best visualization of the primary tumor and extent of soft tissue disease. PET/CT is recommended for assessment of nodal involvement, as well as distant metastases. Both MR imaging and PET/CT are used to follow patients post-treatment to assess for recurrence. This review focuses on the current MR imaging and PET/CT protocols, the utility of these modalities in assessing primary tumors and recurrences, with emphasis on imaging findings which change management and on imaging pitfalls to avoid. It is important to be familiar with the MR imaging and PET/CT appearance of the primary tumor and metastasis, as well as the imaging pitfalls, so that an accurate assessment of disease burden is made prior to treatment.

Adnexal mass in the postmenopausal patient

The adnexal mass in a postmenopausal patient poses an important diagnostic and management dilemma for primary care providers and gynecologists. Postmenopausal women are at a significantly increased risk of gynecologic malignancy; yet even in this population the majority of adnexal masses are benign. Evaluation and management of these lesions centers on the identification of malignancy, especially ovarian cancer, while avoiding unnecessary intervention in patients with benign lesions. Tumor markers and imaging can help in the evaluation of adnexal mass in postmenopausal women. Transvaginal ultrasound has long been considered the imaging modality of choice for the evaluation of adnexal masses. Particularly in the setting of high frequency utilization of transvaginal probes, which project high quality images allowing for detailed descriptions of the macroscopic appearance of the mass, and remains the least expensive of all imaging modalities currently available. For adnexal masses that are highly suspicious for cancer, women should be referred a gynecologic oncologist and facility for optimal care.

PET/MRI and PET/CT in advanced gynaecological tumours: initial experience and comparison

PURPOSE

To compare the diagnostic accuracy of PET/MRI and PET/CT for staging and re-staging advanced gynaecological cancer patients as well as identify the potential benefits of each method in such a population.

MATERIAL AND METHODS

Twenty-six patients with suspicious or proven advanced gynaecological cancer (12 ovarian, seven cervical, one vulvar and four endometrial tumours, one uterine metastasis, and one primary peritoneal cancer) underwent whole-body imaging with a sequential trimodality PET/CT/MR system. Images were analysed regarding primary tumour detection and delineation, loco-regional lymph node staging, and abdominal/extra-abdominal distant metastasis detection (last only by PET/CT).

RESULTS

Eighteen (69.2 %) patients underwent PET/MRI for primary staging and eight patients (30.8 %) for re-staging their gynaecological malignancies. For primary tumour delineation, PET/MRI accuracy was statistically superior to PET/CT (p < 0.001). Among the different types of cancer, PET/MRI presented better tumour delineation mainly for cervical (6/7) and endometrial (2/3) cancers. PET/MRI for local evaluation as well as PET/CT for extra-abdominal metastases had therapeutic consequences in three and one patients, respectively. PET/CT detected 12 extra-abdominal distant metastases in 26 patients.

CONCLUSION

PET/MRI is superior to PET/CT for primary tumour delineation. No differences were found in detection of regional lymph node involvement and abdominal metastases detection.

KEY POINTS

• PET/MRI is superior to PET/CT for primary tumour delineation • PET/CT represents a reliable tool to detect extra-abdominal distant metastasis • PET/MRI might be the preferred imaging modality for staging cervical and endometrial tumours • Whole-body staging for detection and evaluation of extra-abdominal metastases is mandatory.

FDG-PET predicts outcomes of treated bone metastasis following palliative radiotherapy in patients with hepatocellular carcinoma

AIMS

To determine the utility of FDG-PET in predicting long-term infield tumour control after RT in patients with metastatic hepatocellular carcinoma (HCC) to bone.

METHODS

Among 223 patients with HCC skeletal metastases diagnosed, we reviewed 22 patients with 45 total sites treated with RT who had at least two FDG-PETs prior to and after RT. The median RT dose was 42 Gy (range, 22-48) with a median fraction of 3 Gy (range, 2-8). Helical tomotherapy was generally offered for lesions that received higher RT dose (36%). The intrahepatic control rate in all patients was 73% at the time of referral. The ratio of tumour SUV to blood-pool activity SUV (SUV-ratio) was calculated. The primary end-points were infield progression-free survival (infield-PFS) and infield event-free survival (infield-EFS; recurrent and intractable pain or skeletal-related events).

RESULTS

Among 45 sites, 20 had tumour progression and 21 developed events in the previously treated area. A higher SUV-ratio before RT, SUV-ratio decline and higher radiation dose were independently and significantly correlated with better infield-PFS (both P<0.05). The tumours with a pre-RT SUV-ratio≥3.0 and SUV-ratio decline≥40% had significantly better infield-PFS and EFS than those with either a pre-RT SUV-ratio<3.0 or SUV-ratio decline<40% (both P<0.05).

CONCLUSIONS

FDG-PET may help to predict outcomes of infield tumour control following palliative RT for treatment of HCC bone metastases. Tumours with low metabolic uptake before RT or with a minor decline in post-RT SUV-ratio showed poor long-term infield tumour control.

Imaging techniques for the pre-surgical diagnosis of adnexal tumours

A correct diagnosis of any adnexal mass is essential to triage women to appropriate treatment pathways. Several imaging techniques are available that may be used to provide an assessment of a mass before treatment, such as transvaginal ultrasonography, magnetic resonance imaging, computed tomography, and positron emission tomography combined with computed tomography. In this chapter, we focus in depth on the role of transvaginal ultrasonography, as current evidence suggests it is the most appropriate initial imaging investigation to identify and characterise any mass if present in women suspected of having adnexal pathology. Subjective assessment by an experienced ultrasound examiner is the optimal approach to diagnose masses, followed by risk models and rules developed by the International Ovarian Tumor Analysis study. A group of tumours has proven difficult to classify with transvaginal ultrasound, and remain a diagnostic challenge for which accurate second-stage tests would be of value. Some studies suggest that magnetic resonance imaging (MRI), compared with other imaging modalities, may play a role in the assessment of this cohort of 'difficult to classify' adnexal masses. These studies, however, did not report quality of transvaginal ultrasonography (i.e. experience level of the examiner) and lacked uniformity in describing the criteria used to define such 'difficult' masses. On the basis of standardised terminology developed by the International Ovarian Tumor Analysis study to describe adnexal masses, as well as prediction models and rules developed in the course of the study, we propose new criteria that we can use to clearly define complex or 'difficult to classify' adnexal masses to focus the role for second-line imaging tests, such as conventional magnetic resonance imaging combined with dynamic contrast-enhanced or diffusion-weighted sequences on masses where further tests other than ultrasonography would be of value.

Role of SUV(max) obtained by 18F-FDG PET/CT in patients with a solitary pancreatic lesion: predicting malignant potential and proliferation

OBJECTIVES

Maximum standardized uptake value (SUV(max)) is a marker of tumor glucose metabolism detected by [(18)F]-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (PET/CT) and reflects tumor aggressiveness. The aim of the study was to evaluate the value of SUV(max) in differentiating benign from malignant solitary pancreatic lesions and explore the correlation between SUV(max) and tumor proliferative activity.

MATERIALS AND METHODS

F-FDG PET/CT scans were performed in 80 patients with solitary pancreatic lesions who were scheduled for resective surgery. The relationships between SUV(max) and postoperative pathologic diagnosis, histologic grade, and Ki-67 proliferation index (PI) were analyzed.

RESULTS

Of these 80 patients, 54 had malignant lesions. The SUV(max) of malignant tumors (6.3 ± 2.4) was significantly greater than that of benign lesions (2.9 ± 2.0) (P<0.001). Receiver-operating characteristic curve analysis showed that the SUV(max) cutoff value of 3.5 had a high sensitivity (92.6%) and specificity (76.9%) for the diagnosis of malignancies. Among pancreatic cancers with low (Ki-67<5%), moderate (5% ≤ Ki-67<50%), and high (Ki-67 ≥ 50%) PI, SUV(max) increased significantly from 4.2 ± 1.2, through 6.0 ± 1.7, to 8.6 ± 2.5 (P<0.001). The SUV(max) had a positive correlation with Ki-67 PI (P<0.001, r=0.60).

CONCLUSION

The SUV(max) of F-FDG PET/CT can be used in the differential diagnosis of solitary pancreatic lesions and can also aid in the prediction of proliferative activity of pancreatic cancer.

Imaging strategy for early ovarian cancer: characterization of adnexal masses with conventional and advanced imaging techniques

Early detection of ovarian cancer remains crucial for improving patient survival rates. However, early-stage disease is often asymptomatic, and population screening is currently unproven. Adnexal masses may be incidentally detected, but most are identified at ultrasonography (US) in patients who are symptomatic, and most may be characterized as benign or malignant. Indices are available to estimate the risk of malignancy on the basis of clinical and US findings. However, adnexal masses remain indeterminate in some cases, with some benign lesions demonstrating features of malignancy at US. In these cases, use of magnetic resonance (MR) imaging improves the ability to characterize adnexal masses and reduces the number of indeterminate lesions. Establishing the likelihood of malignancy on the basis of imaging features is important to the preoperative detection of early ovarian cancer and profoundly influences referral and management pathways. Conventional and contrast material-enhanced MR imaging are used to evaluate morphologic features, including lesion complexity, signal intensity, and enhancement of solid areas. At dynamic contrast-enhanced MR imaging with semiquantitative analysis, early enhancement characteristics may help differentiate some complex benign and malignant lesions. Diffusion-weighted imaging has a limited but useful role in evaluating adnexal masses: Those with a hypointense solid area on both diffusion-weighted (b = 1000 sec/mm²) and T2-weighted images are likely benign, whereas those that are hyperintense on diffusion-weighted images (b = 1000 sec/mm²) with intermediate signal intensity on T2-weighted images are likely malignant.