Retrospective review of an intraoperative algorithm to predict lymph node metastasis in low-grade endometrial adenocarcinoma
Highlights
► Validates intraoperative algorithm to guide lymphadenectomy in endometrial cancer. ► Mayo algorithm predicts low risk of nodal metastasis and recurrence.
Introduction
Endometrial cancer is the most common gynecologic malignancy in the United States and is a surgically staged cancer. Lymphadenectomy at the time of hysterectomy provides an accurate assessment of the extent of disease, allows targeted adjuvant therapy, and may also provide a therapeutic benefit [1], [2], [3]. Lymphadenectomy also extends surgical time and has been proven to increase the risk of surgically related morbidity as well as lymphocyst and lymphedema formation [4]. Practice patterns vary widely regarding the decision to perform retroperitoneal lymphadenectomy and the extent of that dissection [5]. Many gynecologic oncologists agree that women with “low-risk” endometrial cancer do not require routine lymphadenectomy, but the definition of “low-risk” remains elusive [6].
In 2000, a study performed at the Mayo Clinic identified a subset of endometrial cancer patients, identified via intraoperative frozen section findings, who have no evidence of nodal metastases at the time of hysterectomy and therefore do not appear to benefit from lymphadenectomy. These intraoperative criteria for omitting lymphadenectomy include endometrioid histology, grade 1 or grade 2 tumor, myometrial invasion less than or equal to 50%, greatest tumor diameter less than or equal to 2 cm, and no evidence of any metastatic disease at the time of surgery [7]. This algorithm has never been validated based on intraoperative findings, nor has it been globally incorporated into clinical practice.
The Mayo criteria were developed at an institution with a robust surgical pathology system, such that most surgical specimens are examined exclusively by frozen section as their final pathology result with a reported accuracy of 97.8% [8]. This is in contrast to most other institutions at which only a small subset of tissue samples needing immediate diagnosis are reviewed intraoperatively and frozen pathology results are preliminary, with the final analyses pending standard surgical specimen processing. Multiple prior studies have highlighted the inaccuracies of frozen section analysis in endometrial cancer, raising concern about its use to guide surgical staging procedures. Studies at Duke University, the University of Alabama, and MD Anderson have revealed significant discordance between intraoperative grade and myometrial invasion compared with final pathology results [9], [10], [11]. The applicability of the Mayo algorithm at other institutions with less accurate or less extensive intraoperative pathology assessment remains undetermined. Given the unique surgical specimen processing under which the Mayo criteria were developed as well as the potential clinical benefits of tailoring the decision to perform lymphadenectomy, there is a need to systematically evaluate this algorithm's performance at other institutions.
Section snippets
Materials and methods
A multi-center retrospective chart review was performed using two independently collected institutional endometrial cancer databases from 1977 to 2010 following Institutional Review Board approval from Duke University and the University of Virginia. The individual databases were reviewed to identify all women with preoperative grade 1 or grade 2 endometrial adenocarcinoma, no evidence of metastatic disease at surgery, and who had an intraoperative pathology assessment performed.
Inclusion
Results
Six hundred and two patients were identified with grade 1 or grade 2, non-serous and non-clear cell endometrial adenocarcinoma with no evidence of metastasis at the time of surgery and less than or equal to 50% myometrial invasion on intraoperative pathology analysis. Based on tumor size of less than or equal to 2 cm, 289 patients satisfied the Mayo algorithm for predicting which patients would not benefit from lymphadenectomy (MM cohorts). The remaining 313 patients did not satisfy the Mayo
Discussion
The Mayo algorithm defines a subset of women presenting with endometrial cancer who, based on intraoperative frozen pathology analysis, may avoid morbidity-increasing lymphadenectomy at the time of hysterectomy given the absence of lymph node metastasis in their prior study [7]. Our study attempts to validate the applicability of this algorithm at institutions with more traditional pathology systems. While other studies have validated the characteristics of low-risk disease in final pathology
Conflict of interest statement
None of the authors have any conflict of interest with regard to this work.
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