F-18 fluoro-d-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in planning of surgery and sentinel lymph node screening in vulvar cancers

Identification of groin node metastasis in squamous cell vulval cancer using preoperative [18F] FDG-PET/CT. Can unnecessary lymphadenectomy be prevented?

INTRODUCTION

Vulval cancer is the 4th most common gynaecological cancer. The International Federation of Gynaecology and Obstetrics(FIGO) staging requires a histopathological dissection of the primary tumour and the inguinofemoral lymph nodes(IFLN).However, radiological methods of IFLN assessment often lack accuracy, leading to unnecessary IFLN dissections carrying significant morbidity.

AIM OF THE STUDY

To determine its accuracy of [18F] FDG-PET/CT as a pre-operative assessment tool for the groin lymph node in vulval squamous cell carcinoma.

METHODOLOGY

The predictive value of PET/CT in preoperative assessment of the groin node metastasis was assessed retrospectively in patients with vulval cancer, treated in St. James's Hospital Dublin (2010-2022). SUVmax of the nodal uptake of each inguinal area (if present) was calculated and correlated to histologically confirmed groin metastasis. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of PET/CT in predicating groin node metastasis were calculated. Overall survival was also calculated.

RESULTS

Out of the 200 patients 107(53.3%) had a full histopathological assessment of inguinal area and a PET/CT. Patients had either bilateral or unilateral IFLN histology, yielding 197 groins. The sensitivity of PET/CT for IFLN metastasis was 60.0% and specificity was 92.10%. The PPV was 74.30% and the NPV was 88.60 %. The mean SUVmax was 7(range 1.6-30.0 for metastatic nodes (true positive) and 2.18(range 1.9-3.1) for histologically negative nodes (false positive).

CONCLUSION

This study showed that PET/CT has a moderate sensitivity to identify those at risk of lymph node metastasis. Further prospective studies are required to validate the use of PET-CT in discriminating metastatic from non-metastatic IFLN.

18F-FDG PET/CT detection of primary mammary-like adenocarcinoma of the vulva with multiple metastases: a case report

Mammary-like adenocarcinoma of the vulva is a malignancy with a low incidence rate compared with the squamous cell carcinoma occurring at the same site. We present a rare case of mammary-like adenocarcinoma of the vulva with multiple-organ involvement using 18F-FDG PET/CT. This study indicates that 18F-FDG PET/CT can not only detect the primary lesion but also distinguish the stage of the mammary-like adenocarcinoma of the vulva.

Preoperative prediction model of lymph node metastasis in the inguinal and femoral region based on radiomics and artificial intelligence

OBJECTIVE

To predict preoperative inguinal lymph node metastasis in vulvar cancer patients using a machine learning model based on imaging features and clinical data from pelvic magnetic resonance imaging (MRI).

METHODS

52 vulvar cancer patients were divided into a training set (n=37) and validation set (n=15). Clinical data and MRI images were collected, and regions of interest were delineated by experienced radiologists. A total of 1688 quantitative imaging features were extracted using the Radcloud platform. Dimensionality reduction and feature selection were applied, resulting in a radiomics signature. Clinical characteristics were screened, and a combined model integrating the radiomics signature and significant clinical features was constructed using logistic regression. Four machine learning classifiers (K nearest neighbor, random forest, adaptive boosting, and latent dirichlet allocation) were trained and validated. Model performance was evaluated using the receiver operating characteristic curve and the area under the curve (AUC), as well as decision curve analysis.

RESULTS

The radiomics score significantly differentiated between lymph node metastasis positive and negative patients in both the training and validation sets. The combined model demonstrated excellent discrimination, with AUC values of 0.941 and 0.933 in the training and validation sets, respectively. The calibration curve and decision curve analysis confirmed the model's high predictive accuracy and clinical utility. Among the machine learning classifiers, latent dirichlet allocation and random forest models achieved AUC values >0.7 in the validation set. Integrating all four classifiers resulted in a total model with an AUC of 0.717 in the validation set.

CONCLUSION

Radiomics combined with artificial intelligence can provide a new method for prediction of inguinal lymph node metastasis of vulvar cancer before surgery.

Imaging in Vulval Cancer

Vulval cancer is a rare gynaecological cancer, accounting for 3% of all gynaecological malignancies, with 47,000 cases in 2022 globally. Various imaging modalities are widely used in conjunction with clinical assessment in the diagnosis and staging of vulval cancers; however, there is significant heterogeneity in which modalities are recommended in international guidelines, reflecting the paucity of evidence in this area. We reviewed the current evidence for the role of imaging in vulval cancer. A systematic search of the literature was performed on the PubMed database using the MeSH terms 'vulval neoplasm' and 'diagnostic imaging'. We found that there is insufficient evidence to support the routine use of imaging for primary vulval tumours. For nodal assessment, there is no ideal imaging modality with sensitivity or specificity that is superior to other modalities. For distant metastases, CT CAP and FDG-PET/CT have the most evidence to support their use. In conclusion, the evidence for role of imaging in vulval cancer is limited by the heterogeneity of the study design and diagnostic criteria used in each study and the small sample size and retrospective nature of most studies.

Current Preoperative Management of Vulvar Squamous Cell Carcinoma: An Overview

Vulvar carcinoma is a rare cancer affecting the genital tract, constituting 4% of gynecological tumors. Vulvar squamous cell carcinoma (VSCC) is the most common type. Diagnosis relies on biopsy during vulvoscopy, plus imaging such as ultrasonography (USG), magnetic resonance imaging (MRI) and positron emission tomography (PET). This review aims to lay out a thorough overview as to the current preoperative management of VSCC, both in case of vulvar and lymph node involvement. The data research was conducted using the following databases: MEDLINE, EMBASE, Web of Sciences, Scopus, ClinicalTrial.gov, OVID and Cochrane Library from 2010 to 2024. The selection criteria included only original articles. Seventeen studies were assessed for eligibility. A concordance rate of 62.3% for vHSIL and 65.2% for carcinoma at vulvoscopy, with a sensitivity of 98%, specificity of 40%, PPV (Positive Predictive Value) of 37% and NPV (Negative Predictive Value) of 98% in identifying malignant lesions was found. Regarding the reliability of PET for staging and assessing lymph node involvement, a mean SUV (Standardized Uptake Value) for malignant vulvar lesions of 8.4 (range 2.5-14.7) was reported. In the case of MRI, useful for the evaluation of loco-regional infiltration and lymph node involvement, the ratio of the short-to-long-axis diameter and the reader's diagnostic confidence for the presence of lymph node metastasis yielded accuracy of 84.8% and 86.9%, sensitivity of 86.7% and 87.5%, specificity of 81.3% and 86.2%, PPV of 89.7% and 87.5% and NPV of 76.5% and 86.2%, respectively. A long lymph node axis >10 mm and a short diameter >5.8 mm were found to be predictors of malignancy. At USG, instead, the two main characteristics of potentially malignant lymph nodes are cortical thickness and short axis length; the combination of these ultrasound parameters yielded the highest accuracy in distinguishing between negative and positive lymph nodes. Despite the heterogeneity of the included studies and the lack of randomized clinical trials, this review provides a broad overview of the three imaging tools used for the presurgical management of VSCC. Nowadays, although MRI and PET represent the gold standard, ultrasound evaluation is taking on a growing role, as long as it is carried out by expert sonographer. The management of this rare disease should be always performed by a multidisciplinary team in order to precisely stage the tumor and determine the most suitable treatment approach.

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

OBJECTIVE

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

CONCLUSIONS

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

Groin Surveillance by Serial Ultrasonography Rather Than Sentinel Node Biopsy or Inguinofemoral Lymphadenectomy for Patients with Vulvar Cancer: A Pilot Study

A pilot study was conducted to determine whether 3-monthly groin ultrasonography could eliminate groin dissection after a negative bilateral groin ultrasound in three groups of patients: (i) Those with a unifocal stage 1B squamous cell carcinoma of up to 20 mm in diameter. (ii) Those with an ipsilateral squamous cell carcinoma of any size which extended to within 1 cm either side of the midline. These patients underwent ipsilateral inguinofemoral lymphadenectomy and ultrasonic surveillance of the contralateral groin. (iii) Patients with multifocal invasive lesions with the largest individual focus 20 mm or less in diameter. Three additional patients were added because they either refused groin dissection or were considered unfit for surgery. All ultrasonically positive nodes were confirmed histologically. Thirty-two patients were entered, and no patients were lost to follow-up. Forty-three groins were followed. With a median follow-up of 37 months, three positive nodes (9.4%) were detected. One patient died of her recurrence (3.1%), and 39 groins (90.7%) were preserved. The overall sensitivity of ultrasonic surveillance was 100% (95% CI: 44-100%), with a specificity of 97% (95% CI: 83-99%) and a negative predictive value of 100% (95% CI: 88-100%). This pilot justifies a larger study on serial ultrasonography in lieu of groin dissection in selected patients with vulvar cancer.

Clinical value of metabolic PET parameters of primary vulvar carcinoma

PURPOSE

We aim to establish the prognostic value of metabolic parameters of the primary tumor in patients diagnosed with vulvar squamous cell carcinoma (VSCC) who underwent a pretreatment F-18 FDG PET/CT scan.

MATERIALS AND METHODS

This retrospective study included 47 patients with a histopathologically confirmed diagnosis of VSCC, and who underwent a F-18 FDG PET/CT scan prior to treatment. The disease stage and age at diagnosis, and the maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) values of the primary tumor, based on a baseline PET scan, were recorded. The relationship between these factors, and progression-free survival (PFS) and overall survival (OS) was evaluated.

RESULTS

The mean age of the 47 study patients was 69.6±1.9 years. Among the patients, 18 were in early stage of the disease and 29 were in the advanced stage. The age, and SUVmax, SUVmean, MTV and TLG values were statistically significantly associated with OS and PFS. Furthermore, it was noted that OS and PFS were significantly longer in the early stage patients than in the advanced stage patients, in patients with a tumor size <4cm than those with a tumor size ≥4cm, and in patients with a negative lymph node metastasis than those with a positive lymph node metastasis.

CONCLUSION

Our findings suggest that PET parameters are prognostic factors for VSCC. To the best of our knowledge, this study is the first to investigate the prognostic value of the PET parameters of primary tumors in patients with VSCC, and as such, we believe it contributes to literature.

Cancer of the vulva: 2021 update

Vulvar cancer is an uncommon gynecological malignancy primarily affecting postmenopausal women. There is no specific screening and the most effective strategy to reduce vulvar cancer incidence is the opportune treatment of predisposing and preneoplastic lesions associated with its development. While vulvar cancer may be asymptomatic, most women present with vulvar pruritus or pain, or have noticed a lump or ulcer. Therefore, any suspicious vulvar lesion should be biopsied to exclude invasion. Once established, the most common subtype is squamous cell carcinoma. Treatment of vulvar cancer depends primarily on histology and surgical staging. Treatment is predominantly surgical, particularly for squamous cell carcinoma, although concurrent chemoradiation is an effective alternative, particularly for advanced tumors. Management should be individualized and carried out by a multidisciplinary team in a cancer center experienced in the treatment of these tumors.

A useful update for trainees and specialists regarding the diagnosis, staging, treatment, and some controversies in the management of vulvar neoplasms.

Clinical value of metabolic PET parameters of primary vulvar carcinoma

PURPOSE

We aim to establish the prognostic value of metabolic parameters of the primary tumor in patients diagnosed with vulvar squamous cell carcinoma (VSCC) who underwent a pretreatment 18F FDG PET/CT scan.

MATERIALS AND METHODS

This retrospective study included 47 patients with a histopathologically confirmed diagnosis of VSCC, and who underwent a 18F FDG PET/CT scan prior to treatment. The disease stage and age at diagnosis, the maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) values of the primary tumor, based on a baseline PET scan, were recorded. The relationship between these factors, and progression-free survival (PFS) and overall survival (OS) was evaluated.

RESULTS

The mean age of the 47 study patients was 69.6±1.9 years. Among the patients, 18 were in early stage of the disease and 29 were in the advanced stage. The age, and SUVmax, SUVmean, MTV and TLG values were statistically significantly associated with OS and PFS. Furthermore, it was noted that OS and PFS were significantly longer in the early stage patients than in the advanced stage patients, in patients with a tumor size <4cm than those with a tumor size ≥4cm, and in patients with a negative lymph node metastasis than those with a positive lymph node metastasis.

CONCLUSION

Our findings suggest that PET parameters are prognostic factors for VSCC. To the best of our knowledge, this study is the first to investigate the prognostic value of the PET parameters of primary tumors in patients with VSCC, and as such, we believe it contributes to literature.

Diagnostic performance of preoperative [18F]FDG-PET/CT for lymph node staging in vulvar cancer: a large single-centre study

Purpose

This retrospective study aimed to assess the diagnostic performance of preoperative [¹⁸F]FDG-PET/CT in predicting the groin and pelvic lymph node (LN) status in a large single-centre series of vulvar cancer patients.

Methods

Between January 2013 and October 2018, among all consecutive women with proven vulvar cancer submitted to [¹⁸F]FDG-PET/CT, 160 patients were included. LNs were analysed by two qualitative methods assessing PET information (defined as visual assessment) and a combination of PET and low-dose CT information (defined as overall assessment), respectively, as well as semi-quantitative analysis (LN-SUV_max). Sensitivity, specificity, accuracy, positive and negative predictive values (PPV and NPV) in predicting the groin and pelvic LN status were calculated in the overall study population; a subset analysis of groin parameters in clinically/ultrasonography negative patients was also performed. Histopathology was the reference standard.

Results

All patients underwent vulvar and inguinofemoral LN surgery, and 35 pelvic LN surgery. Overall, 338 LN sites (296 groins and 42 pelvic sites) were histologically examined with 30.4% prevalence of metastatic groins and 28.6% for metastatic pelvic sites. In the overall study population, sensitivity (95% confidence interval, CI), specificity (95% CI), accuracy (95% CI), PPV (95% CI) and NPV (95% CI) at the groin level were 85.6% (78.3–92.8), 65.5% (59.0–72.0), 71.6% (66.5–76.8), 52.0% (44.0–60.1) and 91.2% (86.7–95.8) for visual assessment; 78.9% (70.5–87.3), 78.2% (72.5–83.8), 78.4% (73.7–83.1), 61.2% (52.3–70.1) and 89.4% (85.0–93.9) for overall assessment; and 73.3% (64.2–82.5), 85.0% (80.1–89.8), 81.4% (77.0–85.8), 68.0% (58.8–77.3) and 87.9% (83.4–92.5) for semi-quantitative analysis (SUV_max cut-off value 1.89 achieved by ROC analysis). Similar results were observed in the pelvis-based analysis.

Conclusion

In this large single-centre series of vulvar cancer patients, [¹⁸F]FDG-PET/CT showed good values of sensitivity and NPV in discriminating metastatic from non-metastatic LNs. In routine clinical practice, qualitative analysis is a reliable interpretative criterion making unnecessary commonly used semi-quantitative methods such as SUV_max.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05257-8.

18F-FDG PET and 18F-FDG PET/CT in Vulvar Cancer: A Systematic Review and Meta-analysis

AIM

The aims of this study were to determine the role of 18F-FDG PET/CT in vulvar cancer patients and to extract summary estimates of its diagnostic performance for preoperative lymph node staging.

PATIENTS AND METHODS

PubMed/Medline and Embase databases were searched to identify studies evaluating 18F-FDG PET/CT in vulvar cancer patients. The assessment of methodological quality of the included articles was performed. Per-patient and per-groin pooled estimates, with 95% confidence intervals (CIs), of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic odds ratio (DOR) were calculated.

RESULTS

Ten articles were included in the systematic review, 7 among which evaluated the diagnostic performance of preoperative 18F-FDG PET/CT for lymph node staging. Qualitative per-patient analysis (72 patients from 4 studies) resulted in estimated pooled sensitivity, specificity, PPV, NPV, and DOR of 0.70 (95% CI, 0.44-0.95), 0.90 (95% CI, 0.76-1.04), 0.86 (95% CI, 0.66-1.06), 0.77 (95% CI, 0.56-0.97), and 10.49 (95% CI, 1.68-65.50), respectively. Qualitative per-groin analysis (245 groins from 5 studies) resulted in estimated pooled sensitivity, specificity, PPV, NPV, and DOR of 0.76 (95% CI, 0.57-0.94), 0.88 (95% CI, 0.82-0.94), 0.70 (95% CI, 0.55-0.85), 0.92 (95% CI, 0.86-0.97), and 19.43 (95% CI, 6.40-58.95), respectively.

CONCLUSIONS

Despite limited literature data, this systematic review and meta-analysis revealed that a negative preoperative PET/CT scan may exclude groin metastases in at least early-stage vulvar cancer patients currently unfit for sentinel node biopsy and select those eligible for a less invasive surgical treatment. A positive PET/CT result should otherwise be interpreted with caution. Larger prospective studies are needed to confirm these results and to evaluate the diagnostic value of standardized semiquantitative analysis compared with the qualitative one.

Ultrasound morphometric and cytologic preoperative assessment of inguinal lymph-node status in women with vulvar cancer: MorphoNode study

OBJECTIVE

To assess the accuracy of preoperative ultrasound examination for predicting lymph-node (LN) status in patients with vulvar cancer.

METHODS

This was a single-institution retrospective observational study of all women with a histological diagnosis of vulvar cancer triaged to inguinal surgery within 30 days following ultrasound evaluation between December 2010 and January 2016. For each groin examined, 15 morphological and dimensional sonographic parameters associated with suspicion for LN involvement were examined. A morphometric ultrasound pattern (MUP) was expressed for each groin, classifying the inguinal LN status into five groups (normal; reactive-but-negative; minimally suspicious/probably negative; moderately suspicious; and highly suspicious/positive) according to subjective judgment, followed by stratification as positive or negative for metastasis according to morphometric binomial assessment (MBA). In cases of positive MBA, fine-needle aspiration cytology was performed. Combining the information obtained from MUP and cytologic results, a binomial final overall assessment (FOA) was assigned for each groin. The final histology was considered as the reference standard. Comparison was performed between patients with negative and those with positive LNs on histology, and receiver-operating-characteristics curves were generated for statistically significant variables on univariate analysis, to evaluate their diagnostic ability to predict negative LN status.

RESULTS

Of 144 patients included in the analysis, 87 had negative inguinal LNs and 57 had positive LNs on histology. A total of 256 groins were analyzed, of which 171 were negative and 85 showed at least one metastatic LN on histology. The following parameters showed the greatest accuracy, with the best balance between specificity and sensitivity, in predicting negative LN status: cortical (C) thickness of the dominant LN (cut-off, 2.5 mm; sensitivity, 90.0%; specificity, 77.9%); short-axis (S) length of the dominant LN (cut-off, 8.4 mm; sensitivity, 63.9%; specificity, 90.6%); C/medulla (M) thickness ratio of the dominant LN (cut-off, 1.2 mm; sensitivity, 70.4%; specificity, 91.5%), the combination of S length and C/M thickness ratio (sensitivity, 88.9%; specificity, 82.4%); and the FOA analysis (sensitivity, 85.9%; specificity, 84.2%).

CONCLUSIONS

Preoperative ultrasound assessment, with or without the addition of cytology, has a high accuracy in assessing inguinal LN status in patients with vulvar cancer. In particular, the combination of two ultrasound parameters (S length and C/M thickness ratio) provided the greatest accuracy in discriminating between negative and positive LNs. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The role of preoperative computerized tomography (CT) scan of the pelvis and groin in the management of clinically early staged vulva squamous cell carcinoma

INTRODUCTION

Vulvar squamous cell carcinoma (VSCC) commonly metastasises through groin lymphatics. However, the use of pre-operative imaging in detecting inguinal nodal metastasis before staging surgery or to triage patients for sentinel node biopsy remains unclear. Here, we investigated if pre-operative CT scan, the imaging choice in our cancer centre, influences the overall course of VSCC management in those patients without clinical evidence of groin lymphadenopathy.

METHOD

The study comprised of a prospective cohort of 225 patients with VSCC who underwent staging surgery within a regional tertiary gynaecological cancer centre. Comprehensive information of the cohort's demography, clinicopathological variables and outcome data were collected and analysed. Findings of pre-operative imaging were compared with histological findings of inguinal lymph nodes following groin lymphadenectomy. Statistical analyses were performed using SPSS V24.

RESULTS

Pre-operative CT scan was performed on 116 (56.6%) patients. The sensitivity and specificity of cross-sectional imaging in detecting groin lymphatic metastasis were 59.1% and 77.8%, respectively; while the positive (PPV) and negative predictive value (NPV) were 61.9% and 75.7%, respectively. In patients who had sentinel inguinal nodes biopsy, the sensitivity, specificity, PPV and NPV of CT scan in detecting inguinal node metastasis were 30.0%, 85.7%, 33.3% and 83.7%, respectively. There was no difference in disease-free and overall survival in those who received pre-operative imaging when compared to those who did not.

CONCLUSION

Pre-operative CT scan may be omitted in early stage VSCC prior to surgical staging as it does not affect overall management and surgical outcomes.

FDG-PET for Assessment of Endometrial and Vulvar Cancer

Fluorodeoxyglucose positron emission tomography computed tomography (FDG-PET/CT) provides a comprehensive whole body evaluation in patients with endometrial and vulvar cancer. Here, we discuss the role of FDG-PET/CT in defining the disease extent in patients presenting with these cancers. Detection of lymph node and distant metastases has implications for staging, treatment planning, and patient prognosis. Procedures for image acquisition and interpretation for optimum accuracy and essential elements that should be included in the PET-CT report are described. Common imaging pitfalls are presented and illustrated with examples.

State of the art in vulvar cancer imaging

Vulvar carcinoma is an uncommon tumor that predominantly affects postmenopausal women. Currently, there is no screening procedure for vulvar carcinoma; in most cases, it is diagnosed only when symptoms appear. The most widely used staging system is that developed by the International Federation of Gynecology and Obstetrics. Lymph node status is the most important prognostic factor. We searched the PubMed/Medline database to identify relevant English-language articles on vulvar cancer, with a special focus on its imaging evaluation. Magnetic resonance imaging is useful for local and nodal staging, as well as facilitating the planning of surgical interventions and radiotherapy. Computed tomography or positron-emission tomography/computed tomography can play an important role in nodal and distant disease assessment, whereas ultrasound is often used for image-guided biopsies. Imaging is pivotal for staging and treatment planning in vulvar carcinoma.

Fusion of ultrasound and 3D single-photon-emission computed tomography/computed tomography to identify sentinel lymph nodes in vulvar cancer: feasibility study

OBJECTIVE

To evaluate the feasibility of fusion of ultrasound imaging and three-dimensional (3D) single-photon-emission computed tomography/computed tomography (SPECT/CT) in detecting sentinel lymph nodes in women with vulvar cancer.

METHODS

This was a prospective pilot single-center study. Patients with vulvar cancer who were candidates for sentinel lymph-node biopsy were enrolled between December 2018 and February 2019. Fusion imaging virtual navigation using 3D SPECT/CT and ultrasound was performed to investigate the tumor-draining lymph node. All clinical, imaging, surgical and histological information was collected prospectively and entered into a dedicated Excel file. Feasibility and success of fusion imaging virtual navigation and time needed to perform the three steps of fusion imaging were evaluated.

RESULTS

Ten lymph-node sites were evaluated in five consecutive women with a histological diagnosis of vulvar cancer. Fusion imaging virtual navigation was feasible and completed successfully for all (10/10) draining sites. Median overall time to perform fusion imaging was 32 (range, 25-40) min and the time decreased from the first to the last examination.

CONCLUSIONS

The present study demonstrated that fusion imaging virtual navigation using 3D SPECT/CT and ultrasound is feasible and able to detect sentinel lymph nodes in women with vulvar carcinoma. Fusion imaging using ultrasound for detection of sentinel lymph nodes opens up multiple diagnostic and therapeutic opportunities in gynecological oncology. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Cancer of the vulva

Vulvar cancer is an uncommon gynecological malignancy primarily affecting postmenopausal women. There is no specific screening and the most effective strategy to reduce vulvar cancer incidence is the opportune treatment of predisposing and preneoplastic lesions associated with its development. While vulvar cancer may be asymptomatic, most women present with vulvar pruritus or pain, or have noticed a lump or ulcer. Therefore, any suspicious vulvar lesion should be biopsied to exclude invasion. Once established, the most common subtype is squamous cell carcinoma. Treatment of vulvar cancer depends primarily on histology and surgical staging. Treatment is predominantly surgical, particularly for squamous cell carcinoma, although concurrent chemoradiation is an effective alternative, particularly for advanced tumors. Management should be individualized, and carried out by a multidisciplinary team in a cancer center experienced in the treatment of these tumors.

Emerging Molecular Imaging Techniques in Gynecologic Oncology

Molecular imaging (mainly PET and MR imaging) has played important roles in gynecologic oncology. Emerging MR-based technologies, including DWI, CEST, DCE-MR imaging, MRS, and DNP, as well as FDG-PET and many novel PET radiotracers, will continuously improve practices. In combination with radiomics analysis, a new era of decision making in personalized medicine and precisely guided radiation treatment planning or real-time surgical interventions is being entered into, which will directly impact on patient survival. Prospective trials with well-defined endpoints are encouraged to evaluate the multiple facets of these emerging imaging tools in the management of gynecologic malignancies.

Positron emission tomography-computed tomography for inguinal nodes in vulvar cancer

We aimed to determine the sensitivity and specificity of fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) for the spread of disease to inguinal lymph nodes in vulvar cancer. A retrospective review of vulvar cancer patients who underwent both inguinal nodal sampling and dissection as well as FDG PET-CT was performed, with 21 patients meeting criteria. The sensitivity and specificity of the FDG PET-CT imaging was performed using a combination of maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Using an SUV_maxcutoff of 4.5 or of two times the average liver uptake, we had a 100% sensitivity and 89% specificity for positive inguinal nodes. MTV and TLG did not add to sensitivity or specificity. We conclude that FDG PET-CT has good sensitivity for inguinal nodal spread in vulvar cancer, and either a quantitative or semiquantitative approach is effective.

18F-FDG PET/CT in preoperative staging of vulvar cancer patients: is it really effective?

The aim of this study was to assess the role of 18F-FDG PET/CT in preoperative staging of vulvar cancer patients.29 pts (69 years, range 51-88) with vulvar cancer (clinical apparent stage I-II), underwent preoperative FDG-PET/CT scan followed by radical vulvectomy and bilateral (or monolateral in case of tumor >2 cm from midline) inguinal lymphadenectomy ± sentinel node biopsy. PET/CT images were analyzed in consensus and correlated to histological findings according to a pt-based and a groin-based analyses. SUVmax of the nodal uptake of each inguinal area (if present) was calculated and correlated to histological findings. The presence of distant metastases was also considered and confirmed.PET/CT analysis in consensus resulted negative at the inguinal LN level in 17 pts (10 true negative, 7 false negative) and positive in 12 pts (7 true positive, 5 false positive). Incidence of LN metastases resulted 48%. On pt-based analysis, sensitivity, specificity, accuracy, and negative and positive predictive value of PET/CT in detecting LN metastases were 50%, 67%, 59%, 59%, and 58%, respectively. On a groin-based analysis, considering overall 50 LN-sites, sensitivity, specificity, accuracy, and negative and positive predictive value of PET/CT were 53%, 85%, 73%, 67%, and 76%, respectively. The mean value of SUVmax was 6.1 (range 0.7-16.2) for metastatic nodes, whereas 1.6 (range 0.7 - 5.4) for negative lymph-nodes (P = .007). PET/CT detected pelvic (n = 1) and both pelvic/paraortic (n = 1) nodal metastases.In clinical early stage vulvar cancer FDG PET/CT showed low sensitivity and moderate specificity for N-staging; therefore, it is not an accurate tool for the nodal status assessment. PET/CT may not be cost-effective in detecting the rare event of distant metastases, but further studies are needed.

Applications of PET/MR Imaging in Urogynecologic and Genitourinary Cancers

Positron emission tomograph (PET)-magnetic resonance (MR) is a new modality combining PET and MR. In gynecologic cancers it can be used for staging of cervical and endometrial cancer, planning of radiation therapy in cervical cancer, assessing response to chemotherapy in ovarian cancer, and detection of recurrence in most gynecologic cancers. It is being explored for prostate cancer and other genitourinary cancers, but is still in experimental stages.