REASSESSMENT OF LOW- AND INTERMEDIATE-RISK ENDOMETRIAL CANCER REPORTS BY GYNECOLOGICAL PATHOLOGISTS INCREASES RISK CLASSIFICATION WITHOUT IMPACTING OUTCOME

Introduction: Endometrial cancer (EC) is the fourth most common type of cancer, and the most prevalent gynecological tumor among women in the USA. The review of non-specialist pathology reports by specialist pathologists can lead to significant differences in tumor grades, which may affect patients’ prognosis and treatment. Four histopathological variables allow risk classification in endometrial cancer, namely histological type, histological grade, myometrial invasion, and lymphovascular space invasion. Objective: We investigated whether the reassessment and regrading of risk classification based on the European Society of Medical Oncology (ESMO)-modified criteria carried out by gynecological pathologists influence the outcome of patients initially diagnosed as low- and intermediate-risk endometrial carcinoma (LIREC). Methods: A retrospective cohort of 195 patients diagnosed with LIREC was obtained, and two gynecologic oncology pathologists re-evaluated the cases’ pathological diagnoses carried out by a general pathologist. We updated the cases’ risk classifications by reanalyzing the general pathologists’ reports according to the European Society of Medical Oncology (ESMO) classification. The Kappa concordance score was used to verify the concordance between the general’s and specialized pathologists’ reports, and the new risk classification was correlated with the patients’ DFS. Results: The reassessment and gynecological pathologists’ final reports led to changes in the histological type, histological grade, myometrial invasion, and lymphovascular space invasion in 13.3%, 62,8%, 18.3%, and 11.1% of cases, respectively. The Kappa concordance between the general pathologist’s and the gynecological pathologists’ scores was less than 0.7 for all clinical variables tested. In 54 patients (30%), the risk classification was modified (k = 0.396), of which 30 (55.5%) cases upstaged. The 5-year OS was 94.7%, and 5-year DFS was 89.3%. There was no difference in DFS for patients who had an upstaging in their modified ESMO classification compared to those who maintained their initial risk classification (86.7% vs. 88.0%, p=0.77). Conclusion: Despite the differences in the reports reassessed by expert gynecological pathologists and the change (30%) in patients’ risk classification, there was no difference in their DFS.