Influences of Uterine Adenomyosis on Muscle Invasion and Prognosis of Endometrioid Adenocarcinoma

Objective: Endometrial cancer often coexists with uterine adenomyosis. However, little is known about the clinical characteristics of these cases. Thus, cases of endometrial cancer occurring with and without uterine adenomyosis were compared, and the influences of uterine adenomyosis on the clinical progress of endometrial cancer were examined. Materials and Methods: Of endometrial cancer patients who underwent hysterectomies in our facility from 2002 to 2011, we included only endometrioid adenocarcinoma patients in our study. The patients were divided into 2 groups, adenomyosis group and non-adenomyosis group, according to the presence/absence of uterine adenomyosis. Patient characteristics, stage, histopathological grade, muscle invasion, recurrence, and mortality were retrospectively compared and examined. Results: There were 362 cases of endometrioid adenocarcinoma of the uterine body, of which 121 (33.4%) and 241 cases (66.6%) were in the adenomyosis and nonadenomyosis group, respectively. There were no significant differences with respect to the disease stages or ratios of the histopathological grade between the 2 groups. In the adenomyosis group/nonadenomyosis group, 5-year progression-free survival for International Federation of Gynecology and Obstetrics (FIGO) stages I and II was 89.9%/93.7% and that for stages III and IV was 70.6%/62.0%; the 5-year overall survival was 100%/95.9% for FIGO stages I and II, and 88.0%/73.5% for stages III and IV. There were no significant between-group differences for either progression-free survival or overall survival. When limiting the results to only FIGO stage I endometrioid adenocarcinoma, despite no grade variance between the 2 groups, a significant difference was observed in the ratios of outer-half muscle invasion between the adenomyosis and nonadenomyosis groups (19.5% [17/87] vs 10.1% [16/158], P < 0.05); however, the prognosis was similar in the 2 groups. Conclusions: Uterine adenomyosis is associated with deep myometrial invasion in stage I endometrioid adenocarcinoma; however, it did not affect the recurrence or mortality rates.