Women with ovarian cancer once relied solely on chemotherapy to treat their disease. However, in recent years, treatment options have expanded, and new options are also on the horizon. Read on to learn more about ovarian cancer and how it can be treated.
What are the risk factors and symptoms of ovarian cancer?
The American Cancer Society estimates that, in 2020, about 21,750 American women will be diagnosed with ovarian cancer and 13,940 women will die from the disease. Factors associated with increased risk of ovarian cancer include family history of ovarian cancer, abnormalities in BRCA genes, age (about half of all ovarian cancer patients are women over 63), endometriosis, having never given birth, and having had trouble getting pregnant.
Ovarian cancer is commonly diagnosed at more advanced stages because early-stage ovarian cancer symptoms are often mistaken for benign ailments. Symptoms of advanced-stage ovarian cancer include bloating, belly pain, frequent need to urinate, and quickly feeling full after eating.
How is ovarian cancer diagnosed?
Ovarian cancer is diagnosed using transvaginal ultrasound and a blood test to detect a protein called CA-125. The ultrasound can detect a tumor or mass but cannot tell if the mass is cancerous or benign. CA-125 is measured because it is often found at elevated levels in the bloodstream of people with ovarian cancer. The diagnosis is then confirmed by pathology—laboratory testing of a sample of the tumor cells, usually done after surgery to remove the tumor. If surgery is not an option, an ultrasound- or CT-guided needle biopsy can be used to retrieve a piece of the tumor for pathology testing.
What are the types and prognoses (outlook after diagnosis) of ovarian cancer?
The four most common types of ovarian cancers are serous carcinoma (accounting for 52% of cases), clear cell carcinoma (6%), mucinous carcinoma (6%), and endometrioid carcinoma (10%). Ovarian cancer is also defined by grade—how closely the cancer cells resemble normal cells (a lower grade is more normal, and patients with a lower grade have a better outlook)—and stage, which depends on how much the disease may have spread from the ovaries. The five-year survival rate of stage 1 ovarian cancer is 90%, meaning that about 9 out of 10 patients will still be alive five years after their diagnosis. The five-year survival rate for stage 2 is 70%, stage 3 is 39%, and stage 4 (metastatic, spread to distant organs) is 17%.
What treatments are currently available?
The standard of care for ovarian cancer is surgery and chemotherapy, particularly platinum-based chemotherapy. Ovarian cancer is typically very responsive to chemotherapy; however, it often recurs quickly. Cancer that recurs more than six months after the end of treatment is defined as “platinum-sensitive,” whereas cancer that recurs less than six months after the end of treatment is defined as “platinum-resistant.” Even for platinum-sensitive disease, the duration of time a patient lives with no disease before their cancer progresses decreases with each round of treatment.
Over the past several years, the effectiveness of chemotherapy drugs has increased, due to changes in dosing schedules and how the drugs are administered; intraperitoneal (directly into the abdomen) versus intravenous (through a vein). In addition, two classes of drugs have become standard of care: antiangiogenics, namely bevacizumab (brand name Avastin), and PARP inhibitors. Bevacizumab inhibits the growth of blood vessels, which are essential for cancer growth, and PARP inhibitors kill cancer cells that have impaired DNA-repair capabilities.
PARP inhibitors such as olaparib (Lynparza), niraparib (Zejula), and rucaparib (Rubraca) are most relevant to patients whose tumors have what is known as a homologous recombination deficiency (HRD). That means they have genetic mutations that result in impaired DNA-damage repair, such as BRCA mutations, or have genomic instability—an increased tendency for genetic mutations to arise. Cells with damaged DNA need a protein called PARP to repair their DNA and survive. When PARP activity is blocked by a PARP inhibitor drug, tumor cells with BRCA mutations cannot survive.
PARP inhibitors have also shown some efficacy against tumors without BRCA mutations, and the U.S. Food and Drug Administration (FDA) has approved them for BRCA-normal cancer. The FDA recently approved Zejula as frontline maintenance treatment (treatment given to prevent or delay recurrence) for patients who have had a complete or partial response (their cancer has diminished or disappeared entirely) to first-line platinum-based chemotherapy.
What new treatment options are under development?
Despite the impact that bevacizumab and PARP inhibitors have had on ovarian cancer treatment, there is still no cure for advanced ovarian cancer. There is a need for therapies that provide longer-lasting relief, especially for patients whose cancers are platinum-resistant or platinum-refractory (platinum-based chemotherapy does not work at all), as well as for those with normal BRCA genes.
Over the past year, a few promising therapies have been making their way through clinical trials. These include:
- Vaccines; e.g., DPX-Survivac
- Antibody-drug conjugates (ADC); e.g, Mirvetuximab soravtansine, for which new clinical trial results were published in May 2020
- Targeted therapies; e.g., the ATR inhibitor AZD6738 , the Wee1 inhibitor adavosertib, and the anti-DLL4/VEGF bispecific antibody navicixizumab
- Protein therapies; e.g., AVB-S6-500
- Gene therapies; e.g., ofranergene obadenovec
- Immunotherapies; e.g., the anti-PD-L1 antibody MEDI4736
If you’re wondering whether these newer options might be a good fit for you or a loved one, register to receive a personalized, free Cancer Commons Treatment Options Report.
How can patients access different ovarian cancer treatments?
Patients can access treatments in several ways. Drugs that are approved by the FDA for the patient’s stage and treatment history can be prescribed by any oncologist “on label.” Drugs that are approved for another stage, treatment history, or cancer type can be prescribed “off label,” or possibly accessed through a clinical trial. Drugs that are investigational (not yet FDA-approved for any disease) can be accessed in clinical trials that are evaluating their efficacy towards the goal of getting FDA approval. Another way to get access to investigational drugs is through a “compassionate use” program or trial, in which a drug manufacturer might provide the drug to patients in need (such as patients who cannot travel to a clinical trial, patients for whom no current clinical trial is available, or patients who have no other treatment options).
For information on how to access any of the treatments discussed in this article, I invite you to get support from Cancer Commons.
Centers for Disease Control and Prevention: What Are the Risk Factors for Ovarian Cancer?
Ovarian Cancer Research Alliance: Staging for ovarian cancer