Epithelial ovarian cancer Not a single entity

Epithelial ovarian cancer (EOC) refers to a group of ovarian, tubal or peritoneal cancers with different etiology, histology, molecular profile, microenvironment and biological behavior. Despite this heterogeneity, all patients with EOC are treated similarly. In this thesis, we investigated how treatment can become more individualized, based on tumor and patient characteristics.
In two retrospective cohort studies, we showed that lymph node sampling can be omitted in clinical early stage mucinous EOC and that adjuvant chemotherapy improves survival in early stage high-grade serous EOC.
Advanced stage EOC often presents with peritoneal carcinomatosis which is characterized by multiple miliary and superficial metastases. In three comprehensive reviews, we summarized all scattered data on the physiology and pathophysiology of the peritoneum, the role of the peritoneal microvasculature and of the development of peritoneal metastases. We analyzed the peritoneal microvasculature and microenvironment in patients with peritoneal carcinomatosis and showed that peritoneal microenvironment correlates with survival. Finally, we investigated whether genetic makeup of high-grade serous EOC influences microenvironment and survival. We demonstrated multiple prognostic molecular subgroups among high-grade serous EOC, however, the microenvironment within these molecular subgroups did not influence survival.
Our thesis underlines the presence of heterogeneity of EOC and the importance to acknowledge the various histological, molecular and microenvironment subgroups in research, but even more in treatment decisions.