Prognostic significance and clinicopathological associations of tumor budding and poorly differentiated clusters in endometrioid endometrial carcinoma

Background/aim: Tumor budding (TB) and poorly differentiated clusters (PDCs) are histopathological parameters that have been associated with poor prognosis in various malignancies, particularly colorectal carcinoma. Although numerous studies have demonstrated an association between the microcystic, elongated, and fragmented (MELF) pattern in endometrial carcinomas and lymphovascular invasion as well as lymph node metastasis, the literature regarding TB and PDCs in this context remains limited. This study aimed to investigate the potential associations of the MELF pattern, TB, and PDCs with overall survival, progression-free survival, and clinicopathological parameters in cases of endometrioid endometrial carcinoma (EEC). Materials and methods: A total of 190 cases diagnosed with EEC through hysterectomy specimens between 2010 and 2023, with complete hospital records, were selected from the archives of the Department of Pathology at Manisa Celal Bayar University Faculty of Medicine. Results: The presence of TB and PDCs was significantly associated with high histological grade (p < 0.001), deep myometrial invasion (p < 0.001), lymphovascular invasion (p < 0.001), lymph node metastasis (p < 0.001), cervical stromal involvement (p < 0.001), serosal involvement (p < 0.001), advanced stage (p < 0.001), and larger tumor size (p = 0.042 and p = 0.027, respectively). The presence of TB and PDCs was found to be associated with reduced overall survival (p = 0.001 and p < 0.001, respectively) and reduced progression-free survival (p = 0.043 and p = 0.004, respectively). The MELF pattern was not significantly associated with overall survival (p = 0.772). Conclusion: These findings suggest that the presence of TB and PDCs may be valuable in stratifying prognostic risk in EEC and support the inclusion of these parameters in routine pathology reporting.