Accuracy and Significance of Lymph Node Count in Endometrial Cancer.
Tiffany A Thurow, Irene Check, William Watkin. NorthShore University HealthSystem, Evanston Hospital, IL; University of Chicago Pritzker School of Medicine, IL
Background: The importance of lymphadenectomy (LA) in women with endometrial carcinoma (EC) has been established. Recent studies have tried to define adequacy criteria for lymph node (LN) sampling. The GOG protocol 210 requires 12 LN for eligibility. In our experience, pelvic LN dissections often consist of matted, fatty-replaced LN in which it is difficult to determine an accurate LN count. As a result, studies using LN number as an important parameter may be suspect. In this study, we examine the relationship between LN number and actual LN volume and whether either correlates with the detection of metastases in EC.
Design: 46 cases from 2009 of EC treated with hysterectomy and LA, in which the LA specimens were entirely submitted, were reviewed. Age, tumor type, grade, stage, LA specimen size, and LN number were obtained from pathology reports. The size of actual lymphoid tissue on each slide was measured in two dimensions and assigned a width of 0.3 cm, approximating cassette thickness. Lymphoid volume was calculated using the ellipsoid approximation formula. Regression analysis was performed for correlation.
Results: Patient ages were 41 to 87 years (mean 64). Total LN number per patient ranged from 2 to 41 (median 15, mean 17). 6 patients had positive LN. There was no correlation between the LN number and lymphoid volume (figure 1) or between lymphoid volume and specimen volume (R2=.06).
There was a weak correlation between LN number and specimen volume (figure 2).
LN positivity did not correlate with either LN number (p=.28) or volume (p=.57).
Conclusions: The number of LN identified in LA is variable and does not correlate with lymphoid tissue volume. Variability in LN numbers may result from counting sectioned single LN as multiple LN. A standard method of dissecting pelvic LN should be developed before LN numbers are used in treatment protocols or as study eligibility criteria.
Category: Quality Assurance
Monday, February 28, 2011 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 237, Monday Morning