Reproducibility of measurement of myometrial invasion in endometrial carcinoma

Louis J M Van Der Putten,Ben Davidson,Johanna M A Pijnenborg,Xavier Matias-Guiu,Anneke A M Van Der Wurff,Carla Bartosch,Gemma Toledo,Johan Bulten,Leon F A G Massuger,Koen Van De Vijver,Sonia Gatius,W Glenn Mccluggage

doi:10.1007/s00428-016-2035-5

Abstract

Myometrial invasion (MI) as a percentage (%MI), categorized into <50 or ≥50 %, is an important predictor of prognosis in endometrial carcinoma. Recent studies suggest that tumor-free distance (TFD) to serosa and the absolute depth of invasion (DOI) might be stronger predictors of prognosis. Although reproducibility is important in clinical practice for patient prognostication and treatment, reproducibility of these methods for the measurement of MI is largely unknown. One or two slides from 50 patients with FIGO stage I endometrioid endometrial carcinoma were viewed by seven gynecological pathologists, who were requested to measure %MI, TFD, and DOI. We categorized %MI as <50 % (including no MI) or ≥50 %, TFD as ≤1.75 or >1.75 mm (including no MI), ≤7 or >7 mm (including no MI), and ≤10 or >10 mm (including no MI) and DOI as <4 mm (including no MI) or ≥4 mm. Light’s kappa for multi-rater agreement was calculated. The %MI, TFD, and DOI could be measured in 88, 83, and 79 % of cases, respectively. Kappa was 0.75 for %MI, 0.77, 0.73, and 0.69 respectively for TFD with cutoffs of 1.75, 7, and 10 mm, and 0.59 for DOI. Pathologists reach substantial agreement when measuring %MI and TFD and moderate agreement when measuring DOI. The %MI can be measured in more cases than TFD and DOI. This supports the use of %MI in daily clinical practice, but future studies should compare %MI and TFD more extensively, including inter-observer variability.

Highlights

Endometrial carcinoma is the most common gynecological malignancy in developed countries, and its incidence is increasing [1, 2]
Slides from patients treated for stage I endometrioid endometrial carcinoma at the Radboud university medical center (Radboudumc), Nijmegen, the Netherlands, between January 1999 and December 2009 were reviewed by a gynecological pathologist (JB)
This study shows that gynecological pathologists reach substantial agreement when measuring %myometrial invasion (MI) and tumor-free distance (TFD) and moderate agreement when measuring depth of invasion (DOI)

Summary

Introduction

Endometrial carcinoma is the most common gynecological malignancy in developed countries, and its incidence is increasing [1, 2]. The decision to administer adjuvant radiotherapy to prevent locoregional recurrences relies on the presence of predictors of poor outcome, such as high tumor grade, lymphovascular invasion, deep myometrial invasion (MI), and patient age >60 years [2]. More recently, two other methods of measuring MI have been proposed: tumor-free distance (TFD) to serosa (the distance in millimeters between the deepest point of invasion and the serosa) and absolute depth of invasion (DOI, the distance in millimeters between the endometrial/ myometrial junction and the deepest point of MI). One study comparing TFD and DOI concluded that DOI is a stronger predictor of outcome, but TFD is easier to measure, but kappa statistics were not reported [10]

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Conclusion