Date of Award

January 2026

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Blair McNamara

Abstract

Background: Most patients with vulvar cancer present with early-stage disease, and lymph node status is the most important prognostic factor guiding treatment decisions. However, inguinofemoral lymph node dissection (IFLND) is associated with substantial morbidity, including wound complications and chronic lymphedema. Sentinel lymph node (SLN) biopsy has been adopted as a less morbid alternative to IFLND for select patients with early-stage disease following validation in prospective trials such as GROINSS-V and GOG-173. While current National Comprehensive Cancer Network (NCCN) guidelines outline eligibility criteria for SLN biopsy and general recommendations for management, many aspects of clinical practice, including preoperative imaging strategies, tracer selection for SLN mapping, use of intraoperative frozen section, and management of positive nodes, are less clear. As a result, practice patterns may vary across institutions and clinicians. Aim: The aim of this study was to characterize current practice patterns among academic gynecologic oncologists in the United States regarding inguinal lymph node evaluation during vulvar cancer staging procedures. Specifically, we sought to evaluate variation in preoperative assessment, sentinel lymph node mapping techniques, intraoperative decision-making, and management of positive lymph nodes, as well as institutional barriers to implementation. Methods: An anonymous, non-validated, online electronic survey was distributed to gynecologic oncology faculty affiliated with academic institutions in the United States, which were identified using lists of gynecologic oncology fellowship programs from the Society of Gynecologic Oncology and the Electronic Residency Application Service directories. Email addresses were compiled from publicly available online data. The survey consisted of 23 questions addressing respondent demographics, institutional characteristics, preoperative imaging practices, SLN mapping techniques, surgical decision-making, use of intraoperative frozen section, and management of positive lymph nodes. Survey invitations were distributed in January 2026 with two reminder emails. Responses were collected using Qualtrics. Incomplete responses with fewer than 25% of questions answered were excluded from analysis. Differences between high-volume institutions (>20 vulvar cancer staging procedures annually) and low-volume institutions (≤20 annually) were evaluated using Chi-square and Fisher’s exact tests, with significance defined as p<0.05. This study was deemed exempt by the Yale University Institutional Review Board. Results: A total of 431 gynecologic oncology faculty were identified from 67 academic centers and invited to participate. Eighty-six responses were received and five incomplete responses were excluded, yielding 81 responses for analysis (response rate 18.8%). Respondents varied in practice region, years of practice, and institutional case volume. Institutional practices varied widely. Only 16% of respondents reported a formal institutional pathway for vulvar cancer management, while 62% reported no formal pathway but consistent practices within the group, and 22% reported no standardized practices. The most frequently cited barriers to adoption or optimization of SLN biopsy were nuclear medicine logistics (53%) and low institutional case volume (40%). Preoperative imaging practices demonstrated notable variability. Forty-five percent of respondents reported routinely obtaining imaging beginning at stage I disease, while 34% obtain imaging at stage II or higher. FDG-PET/CT was the most commonly used modality (95%), followed by MRI (23%) and CT (11%). High-volume institutions were significantly more likely to obtain imaging starting at stage I compared with low-volume institutions (p=0.02), while MRI was used more frequently at low-volume centers (p=0.04). For SLN mapping, most respondents reported using dual tracer techniques, most commonly technetium-99m combined with blue dye (35%) or technetium-99m combined with indocyanine green (34%). Tc-99m was typically administered on the morning of surgery with lymphoscintigraphy (70%). Nearly half of respondents (49%) reported not routinely sending sentinel lymph nodes for frozen section, while 44% selectively used frozen section and only 4% used it routinely. The most common reason for deferring frozen section was the preference for ultrastaging on final pathology (80%). When SLN mapping was unsuccessful, the majority (89%) proceeded with unilateral IFLND. Management of positive sentinel nodes showed substantial heterogeneity. When intraoperative frozen section demonstrated a positive node, 69% proceeded with ipsilateral completion IFLND. For micrometastatic disease on final pathology, the most common management strategy was adjuvant radiation therapy to both groins (31%), followed by individualized management with either completion IFLND or radiation (28%). For macrometastatic disease, approximately half of respondents (49%) performed completion IFLND, while others selected radiation therapy or individualized treatment strategies. Conclusion: This national survey of academic gynecologic oncologists demonstrates substantial variation in the evaluation and management of inguinal lymph nodes in vulvar cancer staging procedures. While sentinel lymph node biopsy has been widely adopted in accordance with current guidelines, heterogeneity persists in several aspects of care, particularly in areas where recommendations lack specificity, including preoperative imaging practices, use of intraoperative frozen section, and management of positive nodes. These findings highlight opportunities for further research and guideline refinement to promote greater standardization of care and optimize outcomes for patients with vulvar cancer.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 07/14/2028

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