As the name suggests, ovarian cancer is the cancer of the ovaries. Notably, many ovarian cancers begin at the extreme end of the fallopian tubes, which is contrary to the view that the disease starts only on the ovaries.  A small percentage of women's cancers are ovarian, but it ranks eighth in the list of the leading causes of cancer death. In fact, ovarian cancer high mortality comes after cancers of the lungs, breast, colon or rectum and pancreas. Unfortunately, the majority of cases of this disease are detected at the latest stage which minimizes the treatment chances.

Types of ovarian cancer:

Typically, three different cell types make up the ovaries, each able to produce a different form of cancer:

• Epithelial cell tumors: The outer surface of the ovary is covered by epithelial cells, and the majority of ovarian tumors arise from this surface.
• Germ cell tumor: Cells responsible for eggs (ova) production five rise to germ cell tumors; besides, they typically occur in young adults.
• Stromal tumors: This rare ovarian tumor is the result of structural cells that make estrogen and progesterone and hold the ovary together. Furthermore, this type diagnosis detects the cancer at an early stage.

What causes ovarian cancer?

Unlike other types of cancer, ovarian cancer hasn't been proven to be caused by a particular factor, though there are factors that may increase your risk. A cancerous tumor is a growth of malignant cells in the body that begin in one part but spread to other parts afterwards.

Risk factors:

• Family history: The lifetime risk of ovarian cancer increases by 5 percent for a woman with a history of the disease in one relative; it rises to 7 percent for a woman with a history in two relatives.
• Genetics: For example, hereditary breast and ovarian cancer syndrome accounts for 12% ovarian cancer incidence due to a gene mutation of BRCA1 or BRCA2 genes. Similarly, a person with hereditary nonpolyposis colorectal cancer syndrome has a lifetime risk of 12 percent of developing ovarian cancer.
• Age: With advancing age, it is more likely to progress to a late stage and have a lower survival rate.
• Delayed or no pregnancy: Being a pregnant woman before the age of 26, you're less likely to develop the cancer than one who has not. Similarly, never being pregnant increases the risk.
• Early puberty or late menopause: Indeed, the cancer risk increases when women start menstruating at a young age or when they enter menopause at a later age. Moreover, the same scenario applies if both occurs to the same woman.
• Endometriosis: In endometriosis, the tissue similar to that which lines your uterus grows outside of your uterus. It is often painful and can sometimes be life-threatening.
• Hormone replacement therapy: Taking estrogen hormone replacement to reduce hot flashes and vaginal discomfort because of menopause increases the disease risk.
• Smoking: Research concludes that smoking increases the risk of certain types of cancer, including mucinous epithelial tumors.

Ovarian cancer symptoms:

• Abdominal pain and fullness
• Pelvic pain
• Unusual menses
• Face, back and chest dark-coarse hair growth
• Swelling or bloating
• Constipation or diarrhea
• Quick satiety
• Nausea
• Fatigue
• Excessive urination

Stages of ovarian cancer:

• Stage I: This stage is limited to ovaries where the 5-year survival rate is 90%.
• Stage II: The cancer extends into the pelvis giving a 60-80% 5-year survival rate.
• Stage III: Where the cancer spreads to the peritoneal implants and/or retroperitoneal or inguinal lymph nodes suggesting a 20% 5-year survival rate.
• Stage IV: This stage results in less than 10% 5-year survival rate due to metastasis.

How is ovarian cancer diagnosed:

It is possible to miss symptoms of ovarian cancer at an early stage since they are not specific and can be mistaken for other conditions. In addition, the symptoms lasts for months prior to diagnosis.

• Rectovaginal examination: This method allows detection of abnormalities such as pelvic and abdominal masses that doesn't contribute to the normal shape and size of the pelvic organs. During this exam, the doctor wears a lubricated glove and inserts one finger in the vagina and another finger in the rectum where pressure is applied to the lower abdomen at the same time.
• Radiological imaging: In brief, transvaginal ultrasonography and abdominal and pelvic ultrasonography are the mainstay once the doctor is in doubt. Indeed, both of these methods give a good understanding regarding the size, whereabout and the complexity of the ovarian tumor. Also, various imaging techniques can detect tumor extensions such as CT, pelvic MRI and PET scans.
• Blood test: Such test can detect tumor markers that indicate ovarian tumor. For instance, a CA 125 test is about finding a protein present on ovarian cancer cells' surface.
• Genetic test: Gene changes may increase your risk, so a blood sample is enough for a genetic test.
• Surgical biopsy: This the last resolve due to uncertainty. In fact, it could be hard to diagnose the cancer unless the doctor tests an ovary up-close for tumor signs.

Treatment of ovarian cancer:

In addition to ovarian cancer surgery, gynecologic oncologists can provide chemotherapy to women with the disease.

Debulking surgery: This is a surgical treatment to remove as much tumor cells as possible. As a matter of fact, such surgery gives a better chance of killing tumor cells. It may also be helpful to alleviate symptoms or lengthen the life of the patient. In short, this is the case of a late stage ovarian cancer where the tumor spreads well.

Chemotherapy: It uses chemicals as a way to eliminate cells that divide faster than the normal such as cancer cells. Chemotherapy can either be administered by injection into the vein or taken orally. Besides, it's vital to end tumor cells left after surgery, and it can diminish the number of cancer cells before surgery.

Immunotherapy: In this context, immuno-checkpoint inhibitors in combination with chemotherapy, PARPS, and anti-angiogenic agents shows an efficiency rather than one method at a time.

Vaccines: Researchers investigating ovarian cancer vaccines are targeting tumor antigens such as CA 125, P53 protein and HER-2. Precisely, vaccines basically work by triggering the immune system to destroy cancer cells.

Targeted therapy: By targeting the vulnerabilities within cancer cells, killing them is easy to achieve.

Hormone therapy: This treatment method is efficient for both recurrent and slow-growing ovarian cancer. In other words, hormone therapy drugs block estrogen's contribution to tumor cells growth and thus control the disease.

References:

-Roett, M. A., & Evans, P. (2009). Ovarian cancer: an overview. American family physician, 80(6), 609–616.

-American cancer society "Ovarian cancer"

-Arora T, Mullangi S, Lekkala MR. Ovarian Cancer. [Updated 2022 Jan 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK567760/

-CDC "Basic information about ovarian cancer"

-Featured image credits: https://www.freepik.com/vectors/human-body