Coexistence of uterine adenomyosis is not associated with a better prognosis in endometrioid-type endometrial cancer

Background Prognostic value of accompanying adenomyosis in endometrial cancer is the subject of interest due to their common etiology and co-occurrence frequency. However, it is still unclear whether adenomyosis has a role in the prognosis of endometrial cancer. Aims The aim of this study was to determine the effects of adenomyosis on the prognosis of patients with endometrial cancer. Methods In this study, medical records of 552 patients with endometrioid endometrial cancer who underwent surgery between 2007 and 2017 were retrospectively reviewed. The patients were divided into two groups based on the presence or absence of adenomyosis, and these two groups were compared in terms of the clinicopathological factors and survival outcomes of patients. Results Of these patients, 103 (18.7%) had adenomyosis, and the remaining 449 (81.3%) did not. The endometrial cancer patients with adenomyosis exhibited earlier stages ( p < 0.001), lower tumor grades ( p < 0.001), tumor sizes ≤ 2 cm ( p = 0.002), myometrial invasion < 50% ( p < 0.001), and negative lymphovascular space invasion ( p < 0.001). The 5-year overall survival rate was comparable between the adenomyosis and non-adenomyosis groups (95 vs. 89.1%, respectively; p = 0.085). The presence of adenomyosis was significantly associated with a higher 5-year disease-free survival rate (95.1 vs. 87.9%; p = 0.047), but adenomyosis did not remain as a prognostic factor in multivariate analysis. Conclusion The results of our study showed that the endometrioid endometrial cancer patients with adenomyosis are significantly associated with smaller tumor sizes, less myometrial invasion, lower tumor grades, less lymphovascular space invasion, and earlier FIGO stages. Nevertheless, adenomyosis was not found to be an independent prognostic factor for endometrioid endometrial cancer.