Significance of Adenomyosis on Tumor Progression and Survival Outcome of Endometrial Cancer

To examine the effects of adenomyosis on tumor progression and survival outcome of endometrial cancer patients. This is a retrospective study examining stage I–IV endometrial cancer patients who underwent hysterectomy-based surgical staging (n = 571), and endometrial hyperplasia patients who underwent hysterectomy (n = 213). Clinical demographics, histopathological factors, and survival outcomes were analyzed based on the presence or absence of adenomyosis. Among the endometrial cancer cohort, adenomyosis was observed in 47.5 % of cases and was significantly associated with lower grade (grade 1–2 tumors, 81.2 vs. 73.3 %; p = 0.028), earlier stage (stage I disease, 74.8 vs. 64.3 %; p = 0.023), and lower likelihood of deep myometrial invasion (19.2 vs. 28.2 %; p = 0.039) and cervical invasion (13.7 vs. 21.2 %; p = 0.024) than those without adenomyosis. In survival analysis, endometrial cancer coexisting with adenomyosis was associated with a significantly better disease-free survival (5-year rate, 89.2 vs. 78.2 %; p < 0.001) and overall survival (91.8 vs. 83.9 %; p = 0.004) after hysterectomy. In multivariate analysis, controlling for other significant variables in univariate analysis, presence of adenomyosis remained an independent prognostic factor associated with decreased risk of disease recurrence after surgery (hazard ratio [HR] 0.53; 95 % confidence interval [CI] 0.30–0.92; p = 0.023). Endometrial hyperplasia had a significantly increased incidence of adenomyosis when compared with type I endometrial cancer (grade 1–2 endometrioid adenocarcinoma, n = 411) on multivariate analysis (62.9 vs. 48.9 %; HR 1.88; 95 % CI 1.32–2.69; p < 0.001). Adenomyosis appears to be associated with less aggressive tumor behavior of endometrial cancer, suggesting that it may have inhibitory effects on the progression of this disease.