Review ArticleSentinel lymph node mapping and staging in endometrial cancer: A Society of Gynecologic Oncology literature review with consensus recommendations
Introduction
Endometrial cancer is the most common gynecologic cancer in North America, and worldwide there are approximately 320,000 cases diagnosed annually. Following the Federation of International Gynecology and Obstetrics (FIGO) adoption of surgical staging in 1988, pathology that includes information about the primary tumor as well as lymph node status has guided prognosis and use of adjuvant therapies. Surgical staging is associated with risks of lymphedema, lymphocysts, cellulitis, and damage to nearby nerves. Sentinel lymph node (SLN) assessment has been proposed as a more “targeted” alternative to complete pelvic lymphadenectomy in an effort to secure information about lymph node status for treatment planning, yet minimize collateral damage. The purpose of this article is to review the current literature regarding SLN assessment in endometrial cancer and to improve outcomes for women with this disease.
Section snippets
History of endometrial cancer surgical staging
The value of staging patients with cancer lies in the ability to assess prognosis, plan therapy, and facilitate communication between health care providers. Surgical staging also serves as a research tool to assess treatments among patient groups and for stratification in clinical trials. Prior to 1950, staging endometrial cancer was quite variable between institutions and expert gynecologists. Following the success of standardized staging for cervical cancer in the 1950s, FIGO assumed
History of SLN mapping
Although the orderly progression of lymphatic metastases has been hypothesized for several hundred years, the first report of SLN mapping success was in 1977, using lymphangiography of the penis [12]. The reproducibility of SLN mapping with radiocolloid for patients with cutaneous melanomas quickly followed, but was not more widely accepted until blue dyes emerged as a way to augment radiotracers in the late 1980s [13]. Since then, SLN mapping techniques have been developed for several other
Colorimetric methods
Colorimetric lymphatic mapping refers to the visual detection of lymph channels and nodes using colored dyes in white light. This technique requires the least complex equipment and is applicable to open, laparoscopic, and robotic approaches.
Isosulfan blue is FDA approved for lymphatic mapping. Typically, 3–5 cm3 of a 1% solution are injected into the cervix, after which there is immediate uptake of the dye into lymphatic channels and accumulation in the SLNs within 10–20 min. Delay from injection
SLN pathology
“Ultrastaging” refers to the utilization of enhanced pathology techniques, including deeper serial sections and immunohistochemical (IHC) stains, to increase the detection of malignant cells in SLNs [65]. Strategies for the pathologic processing of SLNs, including the number of level sections examined by routine hematoxylin and eosin (H&E) staining, the depth of sectioning into the tissue block, the interval of microns (μms) between sections, and the use of IHC to identify tumor cells not noted
SLN mapping in endometrial cancer
Several observational studies of SLN mapping in endometrial cancer using either single dyes, combinations of dyes, or Tc-99 radiocolloid injected into the cervix have been reported (Table 1, Table 2) [30], [32], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58]. The reproducibility of the cervical injection technique, high success rate, and low-risk for isolated aortic metastasis has led most
Controversies IN SLN mapping for endometrial cancer
While the current information from SLN mapping studies in endometrial cancer appear quite promising, there are many controversies. The accuracy of the technique across practitioners, appropriate patient selection, optimal treatment algorithm to differentially manage high- and low-grade patients, the role of para-aortic dissection, and the clinical significance of ITC node metastasis require further research.
Future directions
The NCCN SLN mapping algorithm holds great promise as a modern staging strategy for apparent uterine-confined endometrial carcinoma [80]. While awaiting the launch of randomized surgical trials that include an SLN component, several NCI-designated United States cancer centers have embarked on collaborative SLN studies of their endometrial cancer databases, and the results continue to be analyzed. For example, in a comparison of patient cohorts from two separate institutions, the validity of the
Consensus recommendations
Based on the current literature, we recommend that:
- 1.
For patients with endometrial cancer, SLN mapping by cervical injection of tracers accurately predicts the presence of pelvic lymph node metastasis and has a low (< 5%) false-negative rate when the NCCN surgical algorithm is closely followed. It is recommended that completion lymphadenectomy be performed as an “add on” until an individual surgeon's experience documents literature-comparable success of SLN detection and a < 5% false-negative rate.
- 2.
Conflict of interest statement
We declare that there are no direct conflicts of interest associated with this manuscript, except the following relationships:
- •
Dr. Holloway reports personal fees from Intuitive Surgical, Inc., outside the submitted work;
- •
Dr. Boggess reports personal fees from Intuitive Surgical, Inc., outside the submitted work;
- •
Dr. Lowery reports personal fees from AstraZeneca, Inc., outside the submitted work.
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