Unraveling the two entities of endometrioid ovarian cancer: a single center clinical experience.

OBJECTIVE

Due to the increasing prevalence of the benign condition, ovarian carcinoma arising from endometriosis is emerging as a relevant clinical entity with an unclear biological signature. We have investigated clinical and histologic features of endometriosis-associated endometrioid ovarian cancer using an institutional retrospective database.

METHODS

Patients diagnosed with endometrioid ovarian cancer at our institution were divided into two groups according to the fulfillment or not of Sampson's and Scott's criteria for the detection of endometriosis-associated ovarian cancer. Clinical and histological data were reported and compared. Survival analysis was obtained using the log-rank test in an unadjusted Kaplan-Meier method. Multivariate analysis was performed using the Cox proportional hazards regression model to establish independent factors associated with endometriosis-associated endometrioid ovarian cancer and to identify predictors of survival. The degree of concordance was evaluated by Cohen's Kappa measures.

RESULTS

Patients with endometriosis-associated endometrioid ovarian cancer were significantly younger, had a lower disease stage (62% vs 23%; p=0.003), a less prevalent high grade tumor (38% vs 82%; p=0.002) and a higher prevalence of squamous and mucinous metaplasia. The rate of endometrial cancer diagnosis was significantly higher in women with endometriosis-associated endometrioid ovarian cancer (33%) than in other patients (11%) (p=0.04) with a 92% concordance between ovarian and endometrial histologic tumor grade. A significant difference in survival rate could not be demonstrated between patients with or without endometriosis.

CONCLUSIONS

The analysis of a retrospective endometrioid ovarian cancer database may allow to suggest a 40 molecular, morphological and clinical parallelism between endometrial and endometrioid ovarian cancers.