Decorative image

Epithelial ovarian cancer

Epithelial ovarian cancer is the most common type of ovarian cancer. About 90 out of 100 tumours of the ovary (90%) are epithelial.

Epithelial ovarian cancer means the cancer started in the surface layer covering the ovary.


There are various types of epithelial cancers of the ovary. These include:

  • serous
  • endometrioid
  • clear cell
  • mucinous
  • undifferentiated or unclassifiable

Serous epithelial ovarian cancer is the most common type. Your doctor examines the cancer under the microscope. They describe it as either high grade serous or low grade serous ovarian cancer.

Doctors now think that most high grade serous ovarian cancers actually start in cells at the far end of the fallopian tube, rather than the surface of the ovary. These early cancer cells then spread to the ovary and grow.

About 10 in 100 epithelial ovarian cancers (10%) are undifferentiated or unclassifiable. These tumours have cells that are very undeveloped, so it is not possible to tell which type of cell the cancer started from.

Stages and grades

The grade and stage of your cancer is very important because they help your specialist to decide what treatment you need.

The stage of a cancer tells you how far it has grown. In epithelial ovarian cancer there are 4 stages, from 1 to 4:

The grade describes how the cells look under a microscope. The less developed the cells look, the higher the grade. Higher grade cancers grow more quickly than low grade.


Treatment for ovarian cancer includes:

  • surgery
  • chemotherapy
  • radiotherapy
  • biological (targeted) therapy

The treatment you have depends on several things, including:

  • the size of your cancer and whether it has spread (the stage)
  • how abnormal the cells look under the microscope (the grade)
  • your general health

Researchers are investigating in clinical trials whether the rarer types of epithelial ovarian cancer need to be treated any differently to the serous type. But at the moment, they are generally treated in the same way.

Last reviewed: 
20 Dec 2018
  • Newly Diagnosed and Relapsed Epithelial Ovarian Carcinoma: ESMO Clinical Practice Guidelines
    JA Ledermann and others
    Annals of Oncology, 2013. Volume 24, Supplement 6.

  • Cancer and its management (7th edition)
    Tobias J. and Hochhauser D.
    Wiley-Blackwell, 2015

  • Cancer: Principles and practice of oncology (10th edition)
    VT DeVita , TS Lawrence, Rosenberg SA
    Lippincott, Williams and Wilkins, 2015

  • Epithelial Ovarian Cancer
    Scottish Intercollegiate Guidelines Network (SIGN), November 2013

  • Ovarian cancer: recognition and initial management
    National Institute of Health and Care Excellence (NICE), 2011

  • Ovarian cancer
    GC Jayson and others
    Lancet, 2014. Volume 384, Issue 9951

Information and help

Dangoor sponsorship

About Cancer generously supported by Dangoor Education since 2010.