All about ovarian cancer
Ovarian cancer is often called “the cancer that whispers” — it’s not silent, but the early signs are often very subtle or similar to other more common conditions.
The first confirmed case of ovarian cancer was in a woman named Jane Todd Crawford, who thought she was pregnant with twins. It also happened to be the first successful abdominal surgery on record (if you don’t count several documented caesarean sections).
It was late 1809, and she was weeks past her anticipated due date, when surgeon Ephraim McDowell determined she must have a mass, or tumour, on her ovary. He suggested an experimental surgery to remove it. At the time, abdominal surgeries had a very high mortality rate and were largely viewed as immoral. Nevertheless, it appeared to be the only option to save the patient. So, on Christmas Day, in Danville, Kentucky — to avoid crowds forming to protest the surgery — McDowell successfully removed a 22-lb ovarian tumour. With only mild sedation, Crawford reportedly sang hymns and quoted Psalms to calm herself. She not only survived but also lived another 32 years.
Since these times, our understanding of and treatment options for ovarian cancer have expanded immensely.
What is ovarian cancer?
Ovarian cancer starts in the cells that make up the ovary or ovaries.
There are three primary types of ovarian cancer:
- Epithelial tumours are the most common, making up about 80% of all ovarian cases, and they start in the lining covering the ovary
- Stromal tumours, which start in cells that support the growth of follicles
- Germ cell tumours start in the cells responsible for egg production
High-grade serous carcinoma (HGSC) makes up 75% of epithelial ovarian cancers, making it the overall most common type of ovarian cancer. Epithelial-type ovarian cancers are not only the most common but also the most deadly of all gynecologic cancers.
People who have a mutation of their breast cancer (BRCA) genes are at a significantly higher risk of developing ovarian and breast cancer and other cancers such as breast and prostate cancers in males, pancreatic cancer, and stomach cancers.
How is ovarian cancer diagnosed?
Because the symptoms of ovarian cancer can be very subtle, or mistaken for other conditions, ovarian cancer is frequently diagnosed at a late stage, once the cancer has spread outside the ovaries.
Symptoms can include irregular vaginal bleeding, a lump in the pelvic or abdominal area, bloating, a feeling of fullness, abdominal pressure, or digestive issues. Experts recommend seeing a healthcare provider if these symptoms persist for more than two weeks without a clear explanation.
An official diagnosis might be done through a combination of tests, including: a physical pelvic and rectal exam; biopsy of abnormal areas; imaging like an ultrasound, CT, or MRI scan; and blood tests that look for tumour markers.
What is the prognosis for ovarian cancer?
The current five-year survival rate for epithelial ovarian cancer is just 45% overall. When ovarian cancer is found and treated early, the chances of survival are much higher, around 85–90%. Ovarian cancer is graded into four stages to indicate its severity. Ninety percent of patients diagnosed at stage 1 survive five years, compared to just 17% of patients diagnosed at stage 4.
Ovarian cancer also has a high recurrence rate: while only 10% of those treated with Stage 1 cancer will experience a recurrence, those numbers increase to 30% for Stage 2, 70 to 90% for Stage 3, and 90 to 95% for Stage 4.
Ovarian cancer is relatively rare, but disproportionately dangerous: ovarian cancer accounts for only 2.5% of cancer cases in Canadian women, but it is responsible for an alarming 5% of all cancer deaths in this group.
What is the treatment for ovarian cancer?
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Surgery
The primary treatment for most types of ovarian cancer, surgical removal of the tumour and any metastasized disease is often recommended in the front-line treatment of ovarian cancers. -
Chemotherapy
Intravenous chemotherapy is one of the oldest treatments for ovarian cancer, usually delivered in combination with surgery. However, recent advancements using heated chemotherapy, called HIPEC, can also be administered directly to a patient’s abdomen during surgery to improve outcomes in some patients. -
Radiation
Rarely used for ovarian cancer, radiation might be used to treat limited areas of cancer that have regrown after primary therapy, or it might be used to shrink and relieve pain from tumours. -
Targeted therapy
Targeted therapies can include novel antibody-drug conjugates (ADCs), which bind preferentially to cancer cells and destroy them without significantly damaging healthy cells. PARP inhibitors like Olaparib and Niraparib, on the other hand, target certain intracellular enzymes that repair DNA in cancer cells, leading to their eventual death. Other targeted therapies might work by reducing blood flow to a tumour. -
Maintenance therapy
Maintenance therapy is used when the ovarian cancer has been forced into remission. The goal is to prevent or delay subsequent recurrence. Maintenance therapy often uses targeted therapies like PARP inhibitors.
A short history of ovarian cancer
McDowell’s surgery on Crawford was just the first step in many toward the modern ovarian cancer care we know today. Unfortunately, the journey has not been without controversy, including in McDowell’s later practice. In the years after his first successful surgery, McDowell operated on several enslaved women in Kentucky, making him part of another, less positive historical practice in which medical experiments were done on enslaved people without the same consent, anesthesia, or care that white patients were provided.
For the rest of the 1800s, surgical removal remained the only treatment available for ovarian cancer. At the end of the 19th century, though, the elements for radiation were discovered, leading to radiation to treat cancer early in the 1900s. About 50 years later, chemotherapy was created, with the first ovarian cancer patient receiving chemo in 1956.
The 1990s saw the emergence of PARP inhibitors and the discovery of the BRCA1 and BRCA2 genes, which increase the risk of ovarian cancer.
Recently, the development of targeted therapies is once again changing the way we treat ovarian cancer and giving new hope to ovarian cancer patients and their families.
The research happening at The Ottawa Hospital will change the way we treat ovarian cancer tomorrow. Together, we can reshape ovarian cancer care.
