Groin lymph node detection and sentinel lymph node biopsy in vulvar cancer

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.

HPV-associated vulvar carcinoma with sebaceous differentiation

•Sebaceous carcinoma is rare on the vulva and uncommonly associated with HPV.•Pregnancy may play a role in onset or exacerbation of HPV-associated vulvar cancers.•Treatment of vulvar sebaceous carcinoma is local excision and sentinel lymph node dissection with close follow-up.

Sebaceous carcinoma of the vulva treated with sentinel lymph node biopsy: a case report and literature review

Sebaceous carcinoma (SC) is a rare and aggressive cutaneous malignancy. It often occurs on the eyelid, where it is called periocular SC, while extraocular SC mainly occurs on the head and heck. Extraocular vulvar SC is extremely rare; only nine cases have been described in the literature, and the optimal treatment strategy is unknown. We herein report a case of vulvar SC that was successfully treated with local excision in combination with sentinel lymph node biopsy (SNB). A 66-year-old female presented with vulvar discomfort. An 8 mm ulcerated mass was palpable in her left labia minora. Skin biopsy suggested SC. Imaging showed no swelling of the pelvic and inguinal lymph nodes and no metastasis. Sentinel lymph node scintigraphy using technetium-99 m showed three sentinel lymph nodes. The patient underwent local excision with SNB; intraoperative frozen-section examination revealed no nodal metastasis, and no further inguinal lymphadenectomy was performed. The final diagnosis was SC of the vulva, FIGO stage IB (pT1bN0M0). At the 14-month follow-up, she remained asymptomatic and had no signs of recurrence. The scientific rationale for SNB in extraocular SC has not yet been established, although SNB can be considered for periocular SC. However, considering the insufficient data on the management of vulvar SC and the aggressive nature of both periocular and extraocular SCs, SNB can be a reasonable and useful method for avoiding inadequate treatment and reducing the complications caused by unnecessary inguinal lymphadenectomy.

Survey of the clinical practice pattern of using sentinel lymph node biopsy in patients with gynecological cancers in Japan: the Japan Society of Gynecologic Oncology study

BACKGROUND

Sentinel lymph node (SN) biopsy is essential for evaluating survival and minimal treatment-related morbidity associated with cervical, endometrial, and vulvar cancer in Japan. As such, our aim in this study was to evaluate the current practice pattern of using SN biopsy for cervical, endometrial, and vulvar cancer in Japan.

METHODS

We deployed a 47-question survey on the use of SN biopsy for gynecological cancers to 216 gynecological oncology training facilities. The survey included information on the use of SN biopsy for uterine (cervical and endometrial) and vulvar cancers; details on the type, timing, and concentration of tracers used; surgical approach used for SN biopsy; method of biopsy and pathological examination; and facilities' experience with clinical research on SN biopsy.

RESULTS

The response rate was 84% (181/216), with 40 facilities (22%) having experience in SN biopsy for gynecological cancers, 34 (85%) for uterine cancers, and 15 (37%) for vulvar cancers. Radioisotope, indocyanine green (ICG), and blue dyes were available for the detection of uterine cancers in 21 (52%), 25 (62%), and 19 (48%) facilities and for vulvar cancers in 9 (22%), 3 (7%), and 11 (27%) facilities, respectively. Thirty-four facilities (85%) used intraoperative frozen section procedure for diagnosis when possible, with 24 (71%) of these facilities using 2-mm specimen cuts. Diagnosis included pathological examination (85%), immunostaining (57%), and one-step nucleic acid amplification (5%).

CONCLUSION

Increasing research evidence, providing insurance coverage for radioisotope tracers, and increasing the availability of training are expected to increase the use of SN biopsy in Japan.

Proposal for modified inguinofemoral lymphadenectomy derived from investigation of anatomic distribution of sentinel and metastatic nodes in vulvar cancer

OBJECTIVE

We aimed to develop a less invasive inguinofemoral lymphadenectomy (IFL) approach for vulvar cancer based on the investigation of the anatomic distribution of sentinel and metastatic nodes.

METHODS

Patients with vulvar cancer treated by surgery between 1995 and 2019 were retrospectively reviewed. A seven-field method was adopted to assign the anatomic locations for lymph nodes removed via IFL or sentinel node biopsy. Only patients with nodal metastasis or sentinel nodes were included.

RESULTS

A total of 102 patients with eligible data were analyzed. Nodal metastasis was confirmed in 118 groins undergoing IFL; sentinel node detection succeeded in 46 groins. The medial-inguinal field had the highest rate of nodal metastasis involvement (59.3%, 70/118) and sentinel nodes present (73.9%, 34/46). The inferior-femoral field was involved only in one groin with quadruple-field metastases. The lateral-inguinal field was not involved in any groin. Neither the lateral-inguinal nor the inferior-femoral field presented sentinel nodes.

CONCLUSION

The lateral-inguinal and inferior-femoral fields of the groins have a low risk of developing nodal metastasis. Therefore, a modified IFL preserving these fields can be established to reduce surgical morbidity without sacrificing its therapeutic effect.

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.