Omitting Preoperative Lymphoscintigraphy Does Not Decrease Sentinel Lymph Node Detection Rate in Vulvar Cancer

Kasey Marie Roberts

doi:10.11648/j.ijcocr.20180303.13

Abstract

Sentinel lymph nodes in vulvar cancer can be detected in a variety of ways. A method described in GOG-173 involves injection of technetium-99m and isosulfan blue intraoperatively. Lymphoscintigraphy, for which the technetium-99m is injected preoperatively, became required two years into the study due to unpublished evidence that lymphoscintigraphy improved intraoperative sentinel lymph node localization. Despite this amendment, the need for preoperative lymphoscintigraphy has been questioned. The primary objective of this study was to determine the detection rate of sentinel lymph nodes in vulvar cancer when preoperative lymphoscintigraphy is omitted. The secondary objective was to compare the sentinel lymph node detection rate when lymphoscintigraphy is omitted to the rate reported in GOG-173, in which preoperative lymphoscintigraphy was performed. The tertiary objective was to determine lymphoscintigraphy cost at one institution. Patients with vulvar cancer who underwent sentinel lymph node dissection at a single institution from 2008 to 2016 were identified. All but one patient had intraoperative peritumoral injection of both technetium-99m and patent blue dye. Patients were excluded if preoperative lymphoscintigraphy was performed. Information on demographics, pathology, and outcomes were collected. Descriptive statistics were used for patient demographics, tumor characteristics, and the detection rate. A 1-sample proportion test was used to compare our detection rate to data available from GOG-173. Percentages were rounded to the nearest whole number. Current procedural terminology codes were used to estimate lymphoscintigraphy cost. Fifty patients were identified and 32 patients were deemed eligible for the study. The sentinel lymph node detection rate was 97% per patient, which was not statistically different from the rate of 92% reported in GOG-173 (p = 0.347). It was determined that lymphoscintigraphy cost $5,288.22 per imaging study. In this study, omitting preoperative lymphoscintigraphy did not decrease sentinel lymph node detection rates when compared to GOG-173. Furthermore, there is a substantial cost associated with lymphoscintigraphy, although this cost may vary between institutions.

Highlights

Vulvar cancer is the fourth most common gynecologic malignancy with 6,020 new cases and 1,150 deaths attributable to the disease projected to occur in 2017 [1]
When vulvar cancer does spread to lymph nodes (LNs), it most commonly metastasizes to the inguinofemoral LNs, but can metastasize much less commonly to the pelvic LNs [5]
Enrolled patients had sentinel lymph nodes (SLN) identified, excised, and a full inguinal lymphadenectomy performed for analysis

Summary

Introduction

Vulvar cancer is the fourth most common gynecologic malignancy with 6,020 new cases and 1,150 deaths attributable to the disease projected to occur in 2017 [1]. Lymph Node Detection Rate in Vulvar Cancer (IFLND) is associated with complications such as lymphedema, wound break down, and operative site infection in 20 – 70% of cases [6]. Because of the high incidence of complications with IFLND, sentinel lymph node dissection (SLND), which has a complication rate of only 1.9 – 11.7%, began to be studied as a replacement for IFLND in 1994 [7, 8]. One of the prominent study protocols on the safety of SLND in evaluating LN metastases in vulvar cancer is known as GOG-173. For tumors less than 4 cm, the study demonstrated a false negative predictive value of only 2.0% with SLND, supporting SLND as a new method for detecting LN metastases in vulvar cancer [6]

Objectives

Methods

Findings

Conclusion