Ovarian Cancer Basics


Ovarian cancer is a difficult to diagnose and difficult to treat disease. Early New Immunotherapy Shows Promise Against Ovarian Cancerdetection is challenging because symptoms can be mild and vague and could apply to a variety of conditions, such as irritable bowel syndrome or ovarian cysts. The most typical ovarian cancer symptoms include:

  • Swollen or bloated abdomen
  • Persistent pain in the abdomen or pelvis
  • Difficulty eating, constantly feeling full
  • Increased urination

These symptoms are also seen with many other common conditions, as a result, only about 24 percent of women with ovarian cancer are diagnosed early. The rest find out about their disease after it has spread outside the ovaries or fallopian tubes, making successful treatment more difficult to accomplish. However, if the symptoms are new and persistent you should see your health care provider. Other symptoms such as constipation or fatigue, diarrhea, and spotting between periods are also often reported by women with ovarian cancer.

Ovarian cancers, fallopian tube cancers, and primary peritoneal cancers are similar and they are treated the same way. In these diseases, cancer cells form in the epithelial tissue covering the ovaries, in the lining of the fallopian tubes, or in the peritoneal membrane that lines the abdomen and organs in the abdomen. On our website, when the term “ovarian cancer” is used, it includes fallopian tube cancers and primary peritoneal cancers.


One of the most important steps in treating ovarian cancer is staging the disease. In other words, has it spread and, if so, how far? Staging is generally done during surgery, placing the cancer in one of four categories:

From Figure 1 in Cancers 2019, 11(9), 1357; https://doi.org/10.3390/cancers11091357


Stage 1 –
The cancer is limited to one or both ovaries or to the fallopian tubes.

Stage 2 –
The cancer has spread to other areas of the pelvis, uterus, bladder, colon or rectum.

Stage 3 –
The cancer has spread to the abdomen and may also be in the lymph nodes.
Primary peritoneal cancers are stage 3.

Stage 4 –
The cancer has spread to organs outside the abdomen, such as the liver or lungs.

Histology Types

There are three major ovarian cancer tumor types based on where the tumor develops:

  • Epithelial tumors account for 90 percent of ovarian cancers and start from cells on the outside (the epithelium) of the ovaries, the fallopian tubes or the peritoneal membrane surrounding organs in the abdomen or pelvis.
  • Germ cell tumors originate inside the ovaries in the cells that create the eggs. These tumors are rare and generally affect younger women.
  • Stromal tumors are also rare and originate in the connective tissue surrounding the ovaries.

There are also different types (or histologies) of epithelial ovarian cancer. The most common is serous (high grade) and the others are clear cell, mucinous, endometrioid, carcinosarcoma and low-grade serous.

High grade serous and endometriod cancers as well as carcinosarcomas are chemo-sensitive and are similarly treated.

Low grade cancers of serous, mucinous, and endometrioid histology have distinct biologies and different treatment strategies.  For example, hormonal therapy is often used for low grade serous and endometrioid subtypes. Find more information about low grade serous ovarian cancer at https://letstalkaboutlgsoc.com/.

The Role of Genomic Mutations

When people talk about mutations, they are simply highlighting genomic changes. DNA can change relatively frequently through errors in replication during cell division or through environmental exposure to tobacco smoke, chemicals, the sun’s ultraviolet radiation or other agents. Mutation is not necessarily bad – it’s the force that drives evolution. However, in some cases, mutations can be harmful.

Doctors have known for many years that ovarian and breast cancers have a hereditary element –some women diagnosed with ovarian cancer have family members who have had breast or ovarian cancer. Germline (hereditary) mutations in BRCA1 and BRCA2 genes increase the risk of developing ovarian cancer. The standard of care is to test for mutations in these genes whenever a woman is diagnosed with ovarian cancer – even if there is no family history. If she is positive, drugs called PARP inhibitors may be effective.

Tumors have been likened to trees. Maple trees share many common traits, but each individual plant grows in a unique way, generating a branching pattern that is different from other trees. All cancers begin with mutations and, as they grow and spread, acquire even more genomic variations.

Some of these mutations make cells divide faster. Others prevent diseased cells from dying. Still others remove the quality control mechanisms that safeguard DNA, leading to even more mutations. As a result of these widespread variations, ovarian cancer is not one disease but many.

Today, we can differentiate these cancers based on the unique set of gene mutations and the levels of proteins encoded by the genes in each woman’s cancer.