Groin Sentinel Node Biopsy and 18FDG-PET/CT in cN0 Vulvar Cancer Patients Candidate to Standard Lymphadenectomy

Vulvar carcinoma (VC) is a rare disease (4% of gynecological cancers) and the treatment is not yet universally defined. No official guidelines are currently available to define imaging techniques useful for staging. In the pre-operative evaluation of the pateints, imaging should assess nodal status; the available exams are:

• CT or MRI with contrast (abdominal and pelvic with caudal scans for inguinal regions)
• Inguinal ultrasound with US-guided biopsy/fine needle aspiration for suspicious lymph nodes.

The incidence of inguinal and pelvic lymph node metastasis not diagnosed at the pre-operative imaging is 10-35% as assessed after lymphadenectomy at pathology report.

Until 2009, the standard surgical treatment of vulvar cancer was represented by mono or bilateral systematic lymphadenectomy (at least 70% of N0 women underwent a radical surgery with the risk of severe morbidity related to the surgical procedure with no survival benefit).

Inguinal lymphadenectomy shows a high rate of local and systemic complications resulting in a longer hospitalization or recovery, as well as possible delays in adjuvant therapies.

Moreover, severe complications can lead to a further surgery.

Possibile complications described in literature are:

• Lymphedema (up to 70%)
• Infection and postoperative cellulitis (50%)
• Inguinal suture dehiscence (between 22 and 52%)
• Linfocysts (between 7 and 28%)
• Deep vein thrombosis (between 5 and 8%)
• Sepsis (1 -2%)

Since 2009, with the introduction and the validation of sentinel node biopsy (SNB), for some VC it is now possible to obtain a nodal staging with minimally invasive surgery and lower morbidity. However, the SNB technique is indicated if the tumor fits the following selection criteria:

• Infiltrating tumors with a diameter < 40 mm;
• Monofocal tumors;
• Tumors distant more than 1 cm from the midline
• Tumors near the midline with bilateral lymphatic drainage and intraoperative detection of at least one sentinel node for each groin.

Consequently in many tumors diagnosed as N0 at preoperative imaging, SNB technique is not indicated; these tumors still require systematic lymphadenectomy.

In this subset of patients it is important to identify new methods for preoperative evaluation of nodal status or to define a sub-category of patients for which the SNB could be applied.

Objective of the study is to verify, in patients actually off-label for SNB, the accuracy of 18FDG-PET/CT in predicting nodal status, as an indipendent method or associated with the standard pre-operative imaging and the mini-invasive surgical staging.

All patients are submitted to:

• Gynecologic visit
• Vulvar biopsy and possible pelvic examination under anesthesia with the definition of clinical extent of disease
• Evaluation of serum tumor markers: SCC and Ca125
• Inguinal ultrasound and possible US guided FNAC or FNAB on suspicious lymph nodes
• CT scan (abdomen and pelvis) with contrast
• 18FDG-PET/CT
• Lymphangioscintigraphy of inguinofemoral axis

Vulvar surgery may include:

• Wide resection of vulvar disease
• Emivulvectomy (anterior, posterior or lateral)
• Simple vulvectomy
• Radical or ultra-radical vulvectomy (with possible plastic reconstruction)

During inguinal surgery all patients will undergo:

• Sentinel node biopsy mono or bilateral followed by radical bilateral inguinal lymphadenectomy

Statistical analysis will help determine the accuracy and negative predictive value of FDG-PET/CT and sentinel node biopsy in predicting nodal status.