There is no screening or early detection test for ovarian cancer. Some people think the Pap smear can detect ovarian cancer, but it cannot. It can only screen for cervical cancer.
There can be a lot of confusion around the terms early detection, screening, symptom awareness and risk reduction. We hope this section will be a useful guide in better understanding the current landscape in ovarian cancer diagnosis, as well as provide useful information for those who are deemed to be at a higher risk for the disease.
Learn more about early detection and screening for cervical and endometrial cancer.
What is the difference between screening and detection?
Screening is a procedure done in the general population, like a colonoscopy or Pap smear, that looks for pre-cancerous cells, cysts or lesions. Screening looks for irregularities before cancer has a chance to grow, in order to prevent disease. Early detection, on the other hand, is a method of finding cancer in its earliest stages, when intervention can be successful and may help prevent mortality. Mammograms are a well-known early detection tool for breast cancer.
How is the CA-125 blood test used to detect ovarian cancer?
CA-125 is a biomarker, a protein called Cancer Antigen 125, that may be elevated in the blood of those with ovarian cancer. As a tool for ovarian cancer detection (or screening), it is not perfect – CA-125 is also often elevated in the blood of people with endometriosis, fibroids, liver cirrhosis, and who are pregnant (just to name a few conditions). Furthermore, it misses about half of actual ovarian cancer cases, and therefore ovarian cancer screening guidelines do not recommend the CA-125 blood test as a screening tool in the general population. When doctors suspect ovarian cancer, they may measure CA-125 levels in their patients, but the test is FDA approved for assessing treatment effectiveness after diagnosis, as well as monitoring for recurrence. Learn more about the CA-125 blood test.
What is the harm in screening the general population with a CA-125 blood test?
The only way to definitively diagnose ovarian cancer is through surgery. And since CA-125 levels are often elevated for any number of reasons, using that blood test as a screening tool would send otherwise healthy people into unnecessary surgery. In fact, this could cause more harm (both emotional and physical) to more people than it would save lives, as the exploratory surgery itself comes with risk.
Can knowing the symptoms of ovarian cancer save lives?
There is tremendous effort within the ovarian cancer community to share information about signs and symptoms, which are often confused with other conditions. It is important that individuals and healthcare providers are aware of these symptoms, because knowing them can aid in getting an earlier diagnosis and perhaps make treatment a bit easier. Also, correctly identifying symptoms may help patients have time to seek care from a gynecologic oncologist. Studies have shown that ovarian cancer patients treated by gynecologic oncologists have better outcomes.
However, a recent long-range study has shown that earlier detection of ovarian cancer, in fact, does not reduce mortality. This seems counterintuitive, but scientists studied 200,000 women over a period of 20 years to determine the effectiveness of screening using the CA-125 blood test and transvaginal ultrasounds (TVUS). While they did see some stage shifts (more diagnoses of stage 1 or 2 disease v. late stage), they did not see a change in mortality. Doctors and scientists are speculating as to why this is so, and suspect it may be due to the type of ovarian cancer that was detected early. (It’s important to note that ovarian cancer is not one disease; it is an umbrella term for a variety of subtypes of cancer, each with its own origin and trajectory.)
So, while it is still important to know the symptoms of ovarian cancer for the reasons stated above, to say that having this knowledge will save lives is untrue. And it can be harmful as it places the blame on the patient who, for any number of reasons, may not have recognized the symptoms when they first began. It also dilutes energy and resources away from critical research, such as better understanding of disease origins and precision treatment.
Why is it important to know the risk factors for ovarian cancer?
While it may not save lives to know the symptoms of ovarian cancer, it is incredibly important to know the risk factors, especially family history. While ovarian cancer is considered a rare disease, for those with a family history and/or genetic mutation, that risk jumps to 40-50%, or even higher. If you are part of this high risk population, you will be more closely monitored. And the good news is that there are actions you can take to help prevent ovarian cancer.
In 2010, researchers discovered that the most common (and lethal) subtype of ovarian cancer, high-grade serous ovarian carcinoma (HGSOC), actually originates in the fallopian tubes. The pre-cancerous cells move from the fallopian tubes and settle in the ovaries, where they thrive and grow. Doctors are now recommending removal of the fallopian tubes as a way to prevent this type of ovarian cancer, and this procedure, known as salpingectomy, can be done prophylactically during other procedures, such as a hysterectomy or tubal ligation. Learn more about opportunistic salpingectomy and why doctors and researchers feel so hopeful. And be sure to speak with your healthcare provider about risk management for yourself or family members.
What’s on the horizon for breakthroughs in ovarian cancer early detection?
When experts in the field of ovarian cancer talk about early detection, they are working to better understand the origins of the disease (such as discovering that lesions have been found on the fallopian tubes in ovarian cancer patients) and where else in the female reproductive tract these precancerous cells, that will later form tumors in the ovaries, might present. But this type of learning takes time — it could take decades – and so scientists are also focused on discovering better treatments for those who need effective therapies today.