• ovarian
• endometriosis
• cancer

In the Western World ovarian cancer is the fourth leading cause of death from tumors in women, and while having a lower annual incidence compared to breast cancer and precursor lesions of cervical cancer, is the most lethal gynacological malignancy 1 2.
This high mortality rate is due to the fact that in the early stages is asymptomatic, and even if the metaphorical definition of "silent killer" 2 has recently been contested, ovarian cancer lacks specific symptoms until it has spread beyond the pelvis (stage III and IV).1
In fact at the time of diagnosis remote dissemination is present in over 70% of cases, and at this point the rate of 5-year survival is only 21%.1
Over 90% of ovarian cancers are of epithelial origin (EOC or carcinomas) and based on their cell type are classified as serous, mucinous, endometrioid, clear cell, undifferentiated or mixed.
The etiopathogenetic factors of ovarian cancer have been recently revised and the research is focusing on the molecular events of the development of individual histologies.
Molecular and epidemiological studies have documented a significant association between clear cell and endometrioid subtypes with endometriosis 4, which led them to be defined as endometriosis-associated ovarian cancer (EAOC).
Endometriosis is a chronic inflammatory estrogen-dependent disease, characterized by the presence and growth of endometrial-like tissues (glandular epithelium and stroma) outside the uterine cavity 5.
These ectopic endometrial foci are functionally active, respond to cyclical hormones by causing a chronic reactive inflammatory state with the formation of scar tissue and adhesions that besides being cause of infertility and chronic pelvic pain, appear to be possible precursors of sporadic forms of extrauterine malignancies (ovarian and extraovarian).
In addition, even though endometriosis is considered a benign condition, it shares some features with cancer: estrogen-dependent uncontrolled growth, angiogenesis, local invasion, recurrence and propagation distance. Despite endometriosis and ovarian cancer sharing similar risk factors, including early menarche, more regular periods, endometriosis itself can be a risk factor for ovarian cancer.
Endometriosis was first connected with malignancies by Sampson in 1925 6. He described the coexistence of endometriosis and malignant tumors in the same location and proposed further criteria for the establishment of tumors arising from endometriosis. The criteria were later extended by Scott (1953).
Various studies have suggested that atypical endometriosis, the simultaneous presence of cytologic atypia and hyperplasia within the endometrial cysts, may represent a transition from endometriosis to carcinoma.
The most common locations for the coexistence of these diseases are the ovaries and risk of direct malignant transformation of ovarian endometriosis has been estimated as 0.7% to 1.6% over an average of 8 years 8.
Besides the above mentioned types of ovarian cancer associated with endometriosis, links have recently been found between ovarian endometriosis and other malignancies caused by the expansion of clonal epithelial and/or stromal endometrial components such as: seromucinous borderline tumor, squamous cell carcinoma, carcinosarcoma, the adenosarcoma and endometrioid carcinoma stroma 9. All these histological types, along with EAOC, were called by Shih as endometriosis-related neoplasm (ERON).
Clinically ERON, unlike the same malignancies not associated with endometriosis, appear in a younger age, are low grade, are diagnosed at an early stage and therefore have a more favorable prognosis. Nevertheless, some authors publish contradictory results 10.
Since most of the authors estimate that endometriosis develops in 5-15% of women of reproductive age, an increase in knowledge about cancer risk, prognostic factors after endometriosis diagnosis, the relationship between endometriosis treatment and a future risk of malignancy are of great importance, not only for the affected women, but also to clinicians who treat these women on a daily basis and potentially also for treatment guidelines.
The purpose of this thesis is to make a retrospective analysis of the prognosis of ovarian cancers which are not associated with endometriosis to ovarian tumors associated with endometriosis in patients operated on in University Hospital Virgen de la Arrixaca, Murcia (Spain).