The value of 18F-FDG PET/CT in recurrent gynecologic malignancies prior to pelvic exenteration

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.

The Role of Pelvic Exenteration in Cervical Cancer: A Review of the Literature

Pelvic exenteration represents a radical procedure aimed at achieving complete tumor resection with negative margins. Although it is the only therapeutic option for some cases of advanced tumors, it is associated with several perioperative complications. We believe that careful patient selection is related to better oncologic outcomes and lower complication rates. The objectives of this review are to identify the most current indications for this intervention, suggest criteria for case selection, evaluate recommendations for perioperative care, and review oncologic outcomes and potential associated complications. To this end, an analysis of English language articles in PubMed was performed, searching for topics such as the indication for pelvic exenteration for recurrent gynecologic neoplasms selection of oncologic cases, the impact of tumor size and extent on oncologic outcomes, preoperative and postoperative surgical management, surgical complications, and outcomes of overall survival and recurrence-free survival.

Recent Imaging Updates and Advances in Gynecologic Malignancies

Gynecologic malignancies are among the most common cancers in women worldwide and account for significant morbidity and mortality. Management and consequently overall patient survival is reliant upon early detection, accurate staging and early detection of any recurrence. Ultrasound, Computed Tomography (CT), Magnetic resonance imaging (MRI) and Positron Emission Tomography-Computed Tomography (PET-CT) play an essential role in the detection, characterization, staging and restaging of the most common gynecologic malignancies, namely the cervical, endometrial and ovarian malignancies. Recent advances in imaging including functional MRI, hybrid imaging with Positron Emission Tomography (PET/MRI) contribute even more to lesion specification and overall role of imaging in gynecologic malignancies. Radiomics is a neoteric approach which aspires to enhance decision support by extracting quantitative information from radiological imaging.

Relapsed Carcinoma Cervix Presented with Multiple Rare Visceral Metastases: Role of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Carcinoma cervix spread to locoregional lymph nodes. Distance metastases are uncommon and occur through hematogenous routes in advanced stages. The common sites include bone and lungs. Another organ involvement is uncommon. Computed tomography (CT) and magnetic resonance imaging have a crucial role in diagnosing local and distant metastasis. 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) is a sensitive molecular imaging modality for various cancers, including gynecological ones. We present a case of recurrent cervical carcinoma presented with cervical mass and several rare visceral metastases. 18F-FDG PET/CT is a whole-body modality that accurately localized all lesions in a single study.

Patterns of Recurrent Disease in Cervical Cancer

Uterine cervical cancer is one of the most common causes of cancer-related deaths among women worldwide. Patients with cervical cancer are at a high risk of pelvic recurrence or distant metastases within the first few years after primary treatment. However, no definitive agreement exists on the best post-treatment surveillance in these patients. Imaging may represent an accurate method of detecting relapse early, right when salvage treatment could be effective. In patients with recurrent cervical cancer, the correct interpretation of imaging may support the surgeon in the proper selection of patients prior to surgery to assess the feasibility of radical surgical procedure, or may help the clinician plan the most adaptive curative therapy. MRI can accurately define the extension of local recurrence and adjacent organ invasion; CT and 18F-FDG PET/CT may depict extra-pelvic distant metastases. This review illustrates different patterns of recurrent cervical cancer and how imaging, especially MRI, accurately contributes towards the diagnosis of local recurrence and the assessment of the extent of disease in patients with previous cervical cancer. Normal post-therapy pelvic appearance and possible pitfalls related to tissue changes for prior treatments will be also illustrated.

Extended pelvic resection for gynecological malignancies: A review of out-of-the-box surgery

The term 'out-of-the-box surgery' in gynecologic oncology was recently coined to describe the resection of tumor growing out of the endopelvic cavity. In the specific case of pelvic sidewall involvement, a laterally extended pelvic resection may be required. As previously defined by Höckel, this resection requires the en bloc removal of structures including the pelvic sidewall muscles, bones, nerves, and/or major vessels. This complex radical procedure leads to tumor-free margins in more than 75% of the patients, with reliable functional results. The rate of recurrence and overall survival are directly correlated with clear resection margins. Progress in imaging, surgical techniques, and perioperative care currently offer the opportunity to attempt surgical curative resection in selected patients for whom palliative therapy was the only alternative. However, the procedure is associated with a high rate of major postoperative complications affecting up to 60% of patients. Multidisciplinary expert centers are the most likely to achieve this complex surgery with favorable oncological outcomes. The aim of this review is to summarize the key issues of out-of-the-box surgery in gynecologic cancer.

18F-FDG-PET/CT imaging of uterine cervical cancer recurrence in women with and without HIV infection

BACKGROUND

To compare the rate, time and, pattern of recurrence of cervical cancer between patients with and without HIV infection and to determine factors predicting cervical cancer recurrence in patients evaluated by ¹⁸F-FDG-PET/CT.

METHODS

We reviewed the ¹⁸F-FDG-PET/CT images of patients with histologically proven cervical carcinoma who were presenting with suspected recurrence. We extracted epidemiologic data, previous treatment, histologic subtype, HIV status, viral load and CD4 counts from the electronic laboratory database and the referral form for the ¹⁸F-FDG-PET/CT study.

RESULTS

We studied 303 women including 112 HIV-infected patients. FIGO stage III disease was present in 131 patients. Of 198 patients with recurrence, 74 were HIV-infected while 124 were not (P=0.849). HIV infected patients were younger (41.99±9.30 years) compared to HIV-uninfected (50.19±11.09), P<0.001. Local recurrence was present in 125 patients while 100 patients had a distant recurrence. Recurrence occurred at a single site in 88 patients and two or more sites in 110 patients. No significant difference in the recurrent patterns between HIV-infected and uninfected patients. Median time to recurrence was 10.50 months (range: 6.00-156.00) among HIV-infected versus 12.00 months (IQR:7.00-312.00) among the uninfected, P=0.065. FIGO stage III (P=0.042) and the presence of histological sub-types other than SCC (P=0.005) were significant predictors of recurrence. HIV infection by itself was not significant in predicting recurrence (P=0.843).

CONCLUSIONS

HIV infection has no significant impact on the rate, time or pattern of recurrence in women with suspected cervical carcinoma recurrence. Advanced disease and histological variant other than SCC are predictive of recurrence.

Opportunities and Limitations of Pelvic Exenteration Surgery

PURPOSE

The practice of exenterative surgery is sometimes controversial and has garnered a certain scepticism. Surgical studies are difficult to conduct due to insufficient data. The aim of this review is to present the current standing of pelvic exenteration from a surgical, gynaecological and urological point of view.

METHODS

This review is based upon a literature review (MEDLINE (PubMed), CENTRAL (Cochrane) and EMBASE (Elsevier)) of retrospective studies on exenterative surgery from 1993-2020. Using MeSH (Medical Subject Headings) search terms, 1572 publications were found. These were evaluated and screened with respect to their eligibility using algorithms and well-defined inclusion and exclusion criteria. Therefore, the guidelines for systematic reviews (PRISMA) were used.

RESULTS

A complete tumour resection (R0) often represents the only curative option for advanced pelvic carcinomas and their recurrences. A recent systematic review showed significant symptom relief in 80% of palliative patients after pelvic exenteration. Surgical limitations (distant metastases, involvement of the pelvic wall, etc.) are diminished by adequate surgical expertise and close interdisciplinary cooperation. While the mortality rate is low (2-5%), the still relatively high morbidity rate (32-84%) can be minimized by optimizing the perioperative setting. Following exenterations, roughly 79-82% of patients report satisfying results according to PROs (patient-reported outcomes).

CONCLUSION

Due to multimodality treatment strategies combined with extended surgical expertise and patients' preferences, pelvic exenteration can be offered nowadays with low mortality and acceptable postoperative quality of life. The possibilities of surgical treatment are often underestimated. A multi-centre database (PelvEx Collaborative) was established to collect data and experiences to optimize the research in this field.

ACR Appropriateness Criteria® Staging and Follow-up of Primary Vaginal Cancer

Primary vaginal cancer is rare, comprising 1% to 2% of gynecologic malignancies and 20% of all malignancies involving the vagina. More frequently, the vagina is involved secondarily by direct invasion from malignancies originating in adjacent organs or by metastases from other pelvic or extrapelvic primary malignancies. Data on the use of imaging in vaginal cancer are sparse. Insights are derived from the study of imaging in cervical cancer and have reasonable generalizability to vaginal cancer due to similar tumor biology. Given the trend toward definitive chemoradiation for both cancers in all but early stage lesions, principles of postchemoradiation tumor response evaluation are largely analogous. Accordingly, many of the recommendations outlined here are informed by principles translated from the literature on cervical cancer. For pretreatment assessment of local tumor burden and in the case of recurrent vaginal cancer, MRI is the preferred imaging modality. PET/CT has demonstrated utility for the detection of nodal metastatic and unexpected distant metastatic disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

68Ga-DOTA-FAPI-04 PET/CT as a Promising Tool for Differentiating Ovarian Physiological Uptake: Preliminary Experience of Comparative Analysis With 18F-FDG

Objectives: This study aimed to investigate the physiological distribution characteristics of ⁶⁸Ga-DOTA-FAPI-04 in the ovary, and assess the feasibility of early diagnosis of primary ovarian disease with ⁶⁸Ga-DOTA-FAPI-04 PET/CT. Methods: We retrospectively analyzed the data of patients who received ¹⁸F-FDG and ⁶⁸Ga-DOTA-FAPI-04 PET/CT scanning in the Nuclear Medicine Department of our hospital within 3 days from September 2020 to January 2021. We selected the data in which ovaries showed abnormal FDG activity. Patients with abnormal ovarian FDG uptake with focus confirmed by pathological biopsy or clinical follow-up as pathological changes were excluded. The uptake of tracers (¹⁸F-FDG and ⁶⁸Ga-FAPI) was semi-quantitatively analyzed. Results: This study included 14 patients (average age was 38.6). Physiological ovarian uptake was mostly unilateral, and there was no significant difference in SUVmax between the left and right sides (FDGt = 0.272, FAPIt = 0.592). The ovary SUVmax of FDG (4.89 ± 1.84) was statistically significantly higher than that of FAPI (1.53 ± 0.37). The Le/Li ratio on FDG is 3.38 ± 1.81, TBR is 5.81 ± 1.98, while the Le/Li ratio on FAPI is 3.57 ± 1.26, TBR is 0.94 ± 0.19. Conclusion: Our research shows that ovarian functional or pathological changes can be manifested as FDG avid, while ⁶⁸Ga-DOTA-FAPI-04 has no physiological accumulation in the ovary and is not affected by the menstrual cycle. Therefore, ⁶⁸Ga-DOTA-FAPI-04 has unique advantages in the diagnosis of ovarian diseases, and can identify them early and accurately.

Pelvic exenteration for recurrent or persistent gynecologic malignancies: Clinical and histopathologic factors predicting recurrence and survival in a modern cohort

OBJECTIVES

To explore pre-operative factors and their impact on overall survival (OS) in a modern cohort of patients who underwent pelvic exenteration (PE) for gynecologic malignancies.

METHODS

A retrospective review was performed for all patients who underwent a PE from 1/1/2010 through 12/31/2018 at our institution. Inclusion criteria were exenteration due to recurrent or progressive carcinoma of the uterus, cervix, vagina or vulva, with histologically confirmed complete surgical resection of the malignancy. Exclusion criteria included PE for palliation of symptoms without recurrence, and for ovarian or rare histologic malignancies. Univariable and multivariable analysis were performed to identify factors predicting prolonged survival.

RESULTS

Overall, 71 patients met the inclusion criteria. Median age at time of exenteration was 62 years (range, 28-86 years). Vulvar cancer was the most common primary diagnosis (32%); 30% had cervical cancer; 23%, uterine cancer; 15%, vaginal cancer. Median OS was 55.1 months (95% confidence interval (CI): 36-not estimable) with a median follow-up time of 40.8 months (95% CI: 1-116.1). On univariable analysis, age > 62 years (hazard ratio (HR) 2.71, 95% CI 1.27-5.79), American Society of Anesthesia (ASA) 3-4 (HR: 3.41 (95% CI 1.03-11.29), and vulvar cancer (HR 4.19 (95% CI 1.17-14.96) predicted worse OS. Tumor size and prior progression-free interval (PFI) did not meet statistical significance in OS analyses. On multivariable analysis, there were no significant factors associated with worse OS.

CONCLUSIONS

PE performed with curative intent may be considered a treatment option in well-counseled, carefully selected patients, irrespective of tumor size and PFI before exenteration.

The role of imaging in pelvic exenteration for gynecological cancers

Pelvic exenteration (PE) is one of the most challenging gynecologic oncologic surgeries and is an overriding term for different procedures that entail radical en bloc resection of the female reproductive organs and removal of additional adjacent affected pelvic organs (bladder, rectum, anus, etc.) with concomitant surgical reconstruction to restore bodily functions. Multimodality cross-sectional imaging with MRI, PET/CT, and CT plays an integral part in treatment decision-making, not only for the appropriate patient selection but also for surveillance after surgery. The purpose of this review is to provide a brief background on pelvic exenteration in gynecologic cancers and to familiarize the reader with the critical radiological aspects in the evaluation of patients for this complex procedure. The focus of this review will be on how imaging can aid in treatment planning and guide management.

The Association of Tumor Burden by 18F-FDG PET/CT and Survival in Vulvar Carcinoma

PURPOSE

The aim of this study was to assess the impact of 18F-FDG PET/CT metabolic parameters obtained at initial staging of vulva carcinoma on survival in women with and without HIV infection.

PATIENTS AND METHODS

18F-FDG PET/CT images of women with vulva cancer who are planned for definitive therapy were analyzed. SUVmax, SUVmean, MTV, and total lesion glycolysis (TLG) as well as whole-body MTV and whole-body TLG were computed.

RESULTS

Twenty-five women were included with a mean age of 43.44 ± 10.32. The majority of the patients were HIV infected with a median CD4 count of 444.00 cells/mm3. The HIV-infected women are younger at diagnosis than their HIV-uninfected counterparts. All patients presented with inguinofemoral lymph node involvement, whereas half the patients had pelvic nodal metastasis. All the patients with distant visceral or skeletal metastasis were HIV infected. The lungs were the most common site of distant metastasis. When comparing the SUVmax, SUVmean, MTV, TLG, wbMTV, and wbTLG between HIV-infected and HIV-uninfected patients, we did not find statistical differences. Twelve patients (48%) were upstaged to metastatic disease. Seven patients had died at the time of analysis. The wbMTV and wbTLG were significantly higher in nonsurvivors than survivors.

CONCLUSIONS

18F-FDG PET/CT improves initial staging of squamous cell carcinoma among women with and without HIV infection. The whole-body tumor burden assessed by 18F-FDG PET metabolic metrics did not differ between HIV-infected and HIV-uninfected women. A higher whole-burden tumor burden is associated with a higher risk of mortality among women with vulva cancer.

ACR Appropriateness Criteria® Staging and Follow-up of Vulvar Cancer

Vulvar cancer is an uncommon gynecologic tumor and one of several human papillomavirus-associated malignancies. Squamous cell carcinoma is the most prevalent histologic subtype of vulvar cancer, accounting for the majority of cases. Imaging plays an important role in managing vulvar cancer. At initial diagnosis, imaging is useful to assess the size and extent of primary tumor and to evaluate the status of inguinofemoral lymph nodes. If recurrent disease is suspected, imaging is essential to demonstrate local extent of tumor and to identify lymph node and distant metastases. In this publication, we summarize the recent literature and describe the panel's recommendations about the appropriate use of imaging for various phases of patient management including initial staging, surveillance, and restaging of vulvar cancer. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

British Gynaecological Cancer Society (BGCS) cervical cancer guidelines: Recommendations for practice

Cervix cancer in many countries is declining and screening programmes and immunisation will reduce the incidence in the next few decades. This guideline attempts to cover management of invasive disease reflecting diagnosis and imaging including new imaging and sentinel lymph node biopsies. Smaller volume disease is usually managed surgically whereas advanced disease is treated with (chemo)- radiation. It also includes discussion of fertility sparing procedures. Practices are changing frequently for all aspects of care usually in attempts to reduce complications and improve quality of life. The management of advanced disease is treated by chemotherapy and the use of newer agents is also discussed. Other sections discuss specialist situations such as cancer in pregnancy, rare cervical tumours, late effects and supportive measures and fertility preserving approaches.

18F-FDG PET/CT imaging of vulva cancer recurrence: A comparison of PET-derived metabolic parameters between women with and without HIV infection

Objective To assess the patterns of recurrence of vulva cancer on 18F-FDG PET/CT and to compare the 18F-FDG PET metabolic metrics in patients with and without Human Immunodeficiency Virus (HIV).

Methods Maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumour volume (MTV and total lesion glycolysis (TLG) were obtained on Flourine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) images of women referred with suspected or confirmed vulva cancer recurrence. We compared HIV-infected and HIV-uninfected patients regarding pattern disease recurrence, age at diagnosis, and the PET-derived metabolic indices.

Results We analyzed 33 patients with a mean age 50.76 ± 15.78 including 21 HIV-infected women. The majority of patients (94 %) had squamous cell carcinoma and 84.85 % were Blacks. Of the HIV-infected individuals, the median CD4 count was 526.0 cells/mm3 (IQR: 379.0–729.0). HIV infected patients were younger than the HIV uninfected at the time of diagnosis: 40.50 ± 8.87 vs 66.54 ± 9.71 respectively, p < 0.001. We found a local (vulvar) recurrence rate of 75.8 %. Nodal pelvic recurrences were higher in the HIV-infected patients than in the HIV uninfected patients (70 % vs 30 %, p = 0.027). Three patients had distant metastasis and all three were HIV-infected. There was a higher whole-body MTV and TLG among HIV-infected women compared with HIV-uninfected women, 103.39 vs 17.58 and 852.64 vs 101.79, respectively (p < 0.05 for both).

Conclusion HIV-infected women are diagnosed with vulva cancer at a younger age. HIV-infected patients had a higher rate of pelvic lymph node recurrence. There is a higher tumor burden at vulva cancer recurrence among women with HIV infection.

Radiologic Assessment of Groin Lymph Nodes in Pelvic Malignancies

INTRODUCTION

Metastatic involvement of groin nodes can alter radiation therapy planning for pelvic tumors. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) can identify nodal metastases; however, interpretation of PET/CT-positive nodes can be complicated by non-malignant processes. We evaluated quantitative metrics as methods to identify groin metastases in patients with pelvic tumors by comparison with standard subjective interpretive criteria, with pathology as the reference standard.

METHODS

We retrospectively identified patients with vulvar, vaginal, or anal cancers who underwent ¹⁸F-FDG PET/CT before pathologic evaluation of groin nodes between 2007 and 2017. Because patho-radiologic correlation was not possible for every node, one index node identified on imaging was selected for each groin. For each index node, standardized uptake value measurements, total lesion glycolysis, metabolic tumor volume, CT-based volume, and short and long axes were measured. Multivariate logistic regression was used to identify metrics predictive for pathologically positive groins and generate a probabilistic model. Area under the receiver-operating characteristic curves (AUCs) for the model were compared with clinical interpretation from the diagnostic report via a Wald's χ² test.

RESULTS

Of 55 patients identified for analysis, 75 groins had pathologic evaluation resulting in 75 index groin nodes for analysis with 35 groins pathologically positive for malignancy. Logistic regression identified mean standardized-uptake-value (50% threshold) and short-axis length as the most predictive imaging metrics for metastatic nodal involvement. The probabilistic model performed better at predicting pathologic involvement compared with standard clinical interpretation on analysis (AUC 0.91, 95% CI 0.84 to 0.97 vs 0.80, 95% CI 0.71 to 0.89; p<0.01).

DISCUSSION

Accuracy of ¹⁸F-FDG PET/CT for detecting groin nodal metastases in patients with pelvic tumors may be improved with the use of quantitative metrics. Improving prediction of nodal metastases can aid with appropriate selection of patients for pathologic node evaluation and guide radiation volumes and doses.

The effect of different segmentation methods on primary tumour metabolic volume assessed in 18F-FDG-PET/CT in patients with cervical cancer, for radiotherapy planning

Introduction

Gynaecological cancers, including cervical cancer, often require a multidisciplinary approach that includes external beam radiotherapy, chemotherapy, and/or surgical treatment. Biological parameters of the tumour evaluated in ¹⁸F-FDG-PET/CT are used for target volume delineation in radiotherapy planning. The choice of segmentation method may affect the assessment of metabolic tumour volume (MTV) in ¹⁸F-FDG-PET/CT.

Aim of the study

To find the optimal segmentation method for the assessment of primary MTV in ¹⁸F-FDG-PET/CT in cervical cancer patients for radiotherapy planning.

Material and methods

Retrospective analysis was performed on a group of 30 patients with newly diagnosed, histologically confirmed cervical cancer. The primary MTVs were assessed by SUV_max and SUV_mean values; three segmentation methods were used to assess the primary MTV: constant threshold of SUV_max of 2.5, threshold of SUV_max 35%, and threshold of SUV _max 45%. The MTVs were compared with the tumour volumes obtained in magnetic resonance imaging (MRI), which was the "gold standard", to select the best optimal segmentation method reflecting the tumour size. Wilcoxon-Mann-Whitney and t-test were used for statistical analysis.

Results

Depending on the segmentation method chosen, significant differences in the MTVs were obtained (p < 0.001). The highest volumes were obtained using the method based on constant SUV_max of 2.5, while the smallest in case of threshold of SUV_max of 45%. Regarding the volume determined by MRI, a 35% SUV_max threshold was chosen as the most reliable method.

Conclusions

The choice of appropriate segmentation method has a significant impact on the primary MTV assessment in ¹⁸F-FDG-PET/CT in patients with cervical cancer.

Pelvic exenteration as ultimate ratio for gynecologic cancers: single-center analyses of 37 cases

BACKGROUND

Pelvic exenterations are a last resort procedure for advanced gynecologic malignancies with elevated risks in terms of patients' morbidity.

METHODS

This single-center analysis reports surgical details, outcome and survival of all patients treated with exenteration for non-ovarian gynecologic malignancies at our university hospital during a 13-year time period. We collected data regarding patients and tumor characteristics, surgical procedures, peri- and postoperative management, transfusions, complications, and analyzed the impact on survival outcomes.

RESULTS

We identified 37 patients between 2005 and 2013 with primary or relapsed cervical cancer (59.5%), vulvar cancer (24.3%) or endometrial cancer (16.2%). Median age was 60 years and most patients (73%) had squamous cell carcinomas. Median progression-free survival was 26.2 months and median overall survival was 49.9 months. The 5-year survival rates were 34.4% for progression-free survival and 46.4% for overall survival. There were no significant differences in progression-free survival and overall survival with regard to disease entity. Patients with tumor at the resection margins (R1) had a nearly significantly worse progression-free survival (median: 28.5 vs. 7.3 months, HR 2.59, 95% CI 0.98-6.88, p = 0.056) and a significantly worse overall survival (median: not reached vs. 10.9 months, HR 4.04, 95% CI 1.40-11.64, p = 0.010) compared to patients with complete tumor resection (R0). In addition, patients without lymphovascular space invasion had a significantly better progression-free survival (p = 0.017) and overall survival (p = 0.034) then patients with lymphovascular space invasion. We observed complications in 14 patients (37.8%), 10 of those were classified as Clavien-Dindo 3 or 4. There was a trend to worse progression-free survival in patients that suffered complications (p = 0.052). Median total amount of transfused blood products was 4 (range 0-20).

CONCLUSION

Pelvic exenteration is a procedure that provides substantial progression-free survival and overall survival improvement and-in selected patients-can even achieve cure in otherwise hopeless clinical situations. Patients need to be offered earnest counseling for sufficient informed consent with realistic expectations what to expect.

Utility of 18F-FDG-PET/CT imaging in patients with recurrent gynecological malignancies prior to pelvic exenteration

BACKGROUND

In patients with recurrent gynecologic malignancies isolated to the pelvis, pelvic exenteration is a potential option. 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT), is often used to confirm no evidence of metastatic disease.

OBJECTIVE

To assess the impact of PET/CT on clinical management of patients with recurrent gynecologic malignancies being considered for pelvic exenteration.

METHODS

Patients with recurrent gynecological malignancies who underwent PET/CT imaging between 2011 and 2014 were identified. All were considered for pelvic exenteration and underwent conventional imaging with CT +/- pelvic MRI. Patient anthropometric data, disease sites, histology, stage, treatment received, and treatment plan based on PET/CT findings were extracted.

RESULTS

A total of 40 patients met inclusion criteria. In 15 (37.5%) of these patients, results of PET/CT changed the original plan of pelvic exenteration owing to metastatic disease/unresectability (11/15) or no evidence of disease on PET/CT imaging (4/15). Twenty-five (62.5%) patients had their planned surgery after PET/CT with 19 (76%) patients undergoing a completed exenteration procedure. Six (24%) patients with PET/CT indicating isolated pelvic recurrence ultimately had intra-operative findings of extra-pelvic metastasis or nodal disease and therefore the planned surgery was aborted.

CONCLUSION

In nearly 40% of patients with recurrent gynecologic malignancies being considered for radical salvage surgery, PET/CT can significantly alter the originally intended treatment and hence may reduce the number of futile surgical procedures.

Chemoradiotherapy for locally advanced cervix cancer without aortic lymph node involvement: can we consider metabolic parameters of pretherapeutic FDG-PET/CT for treatment tailoring?

PURPOSE

Aim of the study was to assess impact of pretherapeutic FDG-PET/CT metabolic parameters on response to chemoradiotherapy (CRT) and survival in locally advanced cervical cancer (LACC) patients without paraaortic lymph node involvement.

METHODS

LACC patients treated with CRT without macrometastatic involvement after paraaortic surgical staging were included. All patients had received at least 45 Gy radiotherapy and five cycles of platinum-based chemotherapy. High-risk histologies were excluded. Two senior nuclear physician experts in gynaecologic oncology reviewed all PET/CT exams, and extracted tumor SUVmax, MTV, and TLG (standardized uptake value, metabolic tumor volume, and total lesion glycolysis respectively). Response to CRT was assessed with a pelvic MRI done after 45 Gy. Medical charts were reviewed for clinical, pathology, and survival data.

RESULTS

Ninety-three patients were included in the study. The overall survival (OS) rates at 2 and 5 years were 83.0% [95%CI: 72.5-89.8] and 71.2% [57.5-81.2] respectively. The RFS rates at 2 and 5 years were 72.5% [61.5-80.9] and 64.4% [52.3-74.2] respectively. Higher cervical SUVmax and TLG were significantly associated with poor response to CRT. In multivariate analysis, cervical SUVmax was the main predictive factor for OS.

CONCLUSION

Cervical tumor SUVmax was demonstrated to be a non-invasive prognostic biomarker for response to treatment and survival in LACC patients without paraaortic involvement. SUVmax and other PET/CT metabolic parameters require further prospective investigation to help tailoring of local treatment.

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.

Heterogeneity and irregularity of pretreatment 18F-fluorodeoxyglucose positron emission tomography improved prognostic stratification of p16-negative high-risk squamous cell carcinoma of the oropharynx

OBJECTIVES

Human papillomavirus-negative oropharyngeal squamous cell carcinoma (OPSCC) has unfavorable survival outcomes. Two outcomes have been identified based on smoking history and tumor stage. We investigate the prognostic role of pre-treatment positron emission tomography (PET) in high-risk OPSCC.

MATERIALS AND METHODS

We enrolled 147 M0 OPSCC patients with p16-negative staining and a history of heavy smoking (>10 pack-years) or T4 disease. All patients completed primary chemoradiotherapy, and 42% maximum standard uptake values (SUV_max) were used as the threshold for primary tumor. Patients were classified into training and validation cohorts with a ratio of 1:1.5 according to the PET date. Heterogeneity and irregularity indices were obtained. PET parameters with significant impact on progression-free survival (PFS) in receiver operating characteristic curves and univariate Cox models were identified and included in recursive partitioning analysis (RPA) for constructing a prognostic model. The RPA-based prognostic model was further tested in the validation cohort using multivariate Cox models.

RESULTS

Fifty-eight and 89 patients were in the training and validation groups, respectively. Heterogeneity parameter, SUV-entropy (derived from histogram analysis), and irregularity index, and asphericity were significantly associated with PFS. The RPA model revealed that patients with both high SUV-entropy and high asphericity experienced the worst PFS. Results were confirmed in the validation group. The overall concordance index for PFS of the model was 0.75, which was higher than the clinical stages, performance status, SUV_max, and metabolic tumor volume of PET.

CONCLUSIONS

PET prognostic model provided useful prediction of PFS for patients with high-risk OPSCC.

The role of 18F-FDG PET CT in common gynaecological malignancies

[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography (¹⁸F-FDG PET CT) has increasing clinical applications supplementing conventional TVUS, CT and MRI imaging in assessing ovarian, cervical and endometrial cancer. The published literature on the applications of ¹⁸F-FDG PET CT shows its use can have significant impact on patient management by improving staging of the cancers, influencing patient selection for treatment and in detecting early recurrent disease. However, the increasing clinical use of PET CT does not always align with the guidelines, recommendations or expert opinion in the use of PET CT. This article summarizes the existing evidence base for the established clinical applications and the emerging roles for ¹⁸F-FDG PET CT in the common gynaecological malignancies.

Predictive modeling of outcomes following definitive chemoradiotherapy for oropharyngeal cancer based on FDG-PET image characteristics

In this study, we investigate the use of imaging feature-based outcomes research ('radiomics') combined with machine learning techniques to develop robust predictive models for the risk of all-cause mortality (ACM), local failure (LF), and distant metastasis (DM) following definitive chemoradiation therapy (CRT). One hundred seventy four patients with stage III-IV oropharyngeal cancer (OC) treated at our institution with CRT with retrievable pre- and post-treatment 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans were identified. From pre-treatment PET scans, 24 representative imaging features of FDG-avid disease regions were extracted. Using machine learning-based feature selection methods, multiparameter logistic regression models were built incorporating clinical factors and imaging features. All model building methods were tested by cross validation to avoid overfitting, and final outcome models were validated on an independent dataset from a collaborating institution. Multiparameter models were statistically significant on 5 fold cross validation with the area under the receiver operating characteristic curve (AUC)  =  0.65 (p  =  0.004), 0.73 (p  =  0.026), and 0.66 (p  =  0.015) for ACM, LF, and DM, respectively. The model for LF retained significance on the independent validation cohort with AUC  =  0.68 (p  =  0.029) whereas the models for ACM and DM did not reach statistical significance, but resulted in comparable predictive power to the 5 fold cross validation with AUC  =  0.60 (p  =  0.092) and 0.65 (p  =  0.062), respectively. In the largest study of its kind to date, predictive features including increasing metabolic tumor volume, increasing image heterogeneity, and increasing tumor surface irregularity significantly correlated to mortality, LF, and DM on 5 fold cross validation in a relatively uniform single-institution cohort. The LF model also retained significance in an independent population.

Role of MR Imaging and FDG PET/CT in Selection and Follow-up of Patients Treated with Pelvic Exenteration for Gynecologic Malignancies

Pelvic exenteration (PE) is a radical surgical procedure used for the past 6 decades to treat locally advanced malignant diseases confined to the pelvis, particularly persistent or recurrent gynecologic cancers in the irradiated pelvis. The traditional surgical technique known as total PE consists of resection of all pelvic viscera followed by reconstruction. Depending on the tumor extent, the procedure can be tailored to remove only anterior or posterior structures, including the bladder (anterior exenteration) or rectum (posterior exenteration). Conversely, more extended pelvic resection can be performed if the pelvic sidewall is invaded by cancer. Preoperative imaging evaluation with magnetic resonance (MR) imaging and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is central to establishing tumor resectability and therefore patient eligibility for the procedure. These imaging modalities complement each other in diagnosis of tumor recurrence and differentiation of persistent disease from posttreatment changes. MR imaging can accurately demonstrate local tumor extent and show adjacent organ invasion. FDG PET/CT is useful in excluding nodal and distant metastases. In addition, FDG PET/CT metrics may serve as predictive biomarkers for overall and disease-free survival. This pictorial review describes different types of exenterative surgical procedures and illustrates the central role of imaging in accurate patient selection, treatment planning, and postsurgical surveillance.

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.

Volume-based quantitative FDG PET/CT metrics and their association with optimal debulking and progression-free survival in patients with recurrent ovarian cancer undergoing secondary cytoreductive surgery

OBJECTIVE

Our aim was to evaluate the associations between quantitative (18)F-fluorodeoxyglucose positron-emission tomography (FDG-PET) uptake metrics, optimal debulking (OD) and progression-free survival (PFS) in patients with recurrent ovarian cancer undergoing secondary cytoreductive surgery.

METHODS

Fifty-five patients with recurrent ovarian cancer underwent FDG-PET/CT within 90 days prior to surgery. Standardized uptake values (SUVmax), metabolically active tumour volumes (MTV), and total lesion glycolysis (TLG) were measured on PET. Exact logistic regression, Kaplan-Meier curves and the log-rank test were used to assess associations between imaging metrics, OD and PFS.

RESULTS

MTV (p = 0.0025) and TLG (p = 0.0043) were associated with OD; however, there was no significant association between SUVmax and debulking status (p = 0.83). Patients with an MTV above 7.52 mL and/or a TLG above 35.94 g had significantly shorter PFS (p = 0.0191 for MTV and p = 0.0069 for TLG). SUVmax was not significantly related to PFS (p = 0.10). PFS estimates at 3.5 years after surgery were 0.42 for patients with an MTV ≤ 7.52 mL and 0.19 for patients with an MTV > 7.52 mL; 0.46 for patients with a TLG ≤ 35.94 g and 0.15 for patients with a TLG > 35.94 g.

CONCLUSION

FDG-PET metrics that reflect metabolic tumour burden are associated with optimal secondary cytoreductive surgery and progression-free survival in patients with recurrent ovarian cancer.

KEY POINTS

• Both TLG and MTV were associated with optimal tumour debulking. • There was no significant association between SUVmax and tumour debulking status. • Patients with higher MTV and/or TLG had significantly shorter PFS. • SUVmax was not significantly related to PFS.

Magnetic resonance imaging/positron emission tomography provides a roadmap for surgical planning and serves as a predictive biomarker in patients with recurrent gynecological cancers undergoing pelvic exenteration

OBJECTIVE

Magnetic resonance imaging (MRI) is the modality of choice for staging gynecological cancers owing to its superb soft tissue resolution, whereas F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) allows the assessment of glycolytic activity within the tumor microenvironment. In this study, we evaluated the incremental value of fused MRI/PET over MRI or fluorodeoxyglucose PET/CT alone for assessing local disease extent in patients with recurrent gynecological cancers undergoing pelvic exenteration and determined the associations between imaging findings and clinical outcomes in this patient population.

MATERIALS AND METHODS

The institutional review board approved this retrospective, Health Insurance Portability and Accountability Act (HIPAA)-compliant study of 31 patients who underwent pelvic MRI and PET/CT 3 months or less before pelvic exenteration for recurrent cancers of the uterine cervix, corpus, or vulva/vagina. Using a 1 to 5 scale (1, definitely not present; 5, definitely present), 2 readers independently evaluated MRI, PET/CT, and fused MRI/PET images for the presence of bladder, rectum, and pelvic sidewall invasion. Surgical pathology constituted the reference standard. Measurements of diagnostic accuracy, interreader agreement, and associations between imaging findings and progression-free survival and overall survival were calculated.

RESULTS

Compared with MRI or PET/CT, fused MRI/PET correctly improved readers' diagnostic confidence in detecting bladder, rectum, or pelvic sidewall invasion in up to 52% of patients. Interreader agreement was consistently in the highest ("almost perfect") range only for MRI/PET (κ = 0.84-1.0). The highest sensitivities (0.82-1.0), specificities (0.91-1.0), and predictive values (0.80-1.0) were consistently achieved with fused MRI/PET (although the differences were not statistically significant [P > 0.05]). Pelvic sidewall invasion on MRI/PET was the only finding significantly associated with both progression-free and overall survival for both readers (P = 0.0067-0.0440).

CONCLUSIONS

In patients with recurrent gynecological cancers undergoing pelvic exenteration, fused MRI/PET served as a predictive biomarker and yielded greater diagnostic confidence and interreader agreement than either MRI or PET/CT.