Over 20,000 women are diagnosed with ovarian cancer every year. So why is screening for the disease so difficult?
Despite ovarian cancer’s reputation for being a devastating disease, what most people don’t realize is that when it’s detected early enough, it has a better than 90% cure rate. The problem is, it’s not an easy disease to diagnose, especially in its nascent stages, so only 20% of cases are caught early on.
It’s important to remember that there isn’t just one ovarian cancer; there are many different types that are more likely to occur at different life stages. In fact, researchers have identified over 30 types, but these three are the most common:
Epithelial: Over 90% of ovarian cancers are epithelial, which means the cancer cells are located on the outer layer of the ovary. Most epithelial tumors are benign, but when they’re malignant, they’re not usually caught until the disease has advanced about 70% of the time.
Stromal: These are a rare class of tumor (only 3 – 5% of cases) which forms in the connective tissue that holds the ovary together and produces estrogen and progesterone.
Germ Cell: These tumors develop in the cells that produce the ova, and are more likely to impact a single ovary, rather than both. When you hear about a teen or young woman being diagnosed with ovarian cancer, it’s usually germ cell. The good news is, about 90% of these cases can not only be cured, but the woman’s fertility can also be preserved.
One thing that all these different types of cancer have in common is that they’re tricky to diagnose. Because the symptoms of ovarian cancer are non-specific and can be misattributed to anything from menopause to last night’s sketchy supper, most women don’t even mention their symptoms to their doctors until they become severe. And then there’s the lack of any widely available screening test for the disease.
Yearly pelvic exams and pap smears can screen for many different conditions—STDs, pregnancy, various infections, along with gynecological cancers of the cervix, uterus, fallopian tube, and vulva. If your gynecologist includes a rectovaginal exam, they can check and see how the ovaries feel, but a pelvic exam alone is not an effective screening mechanism for this kind of cancer.
While we have mammograms to scan for breast cancer (though they’re not 100% accurate), colonoscopies which reveal anything suspicious lurking in the colon or rectum, and cervical cancer which can be diagnosed via a pap smear or HPV test, unless there’s a family history of ovarian cancer along with recurring symptoms, most gynecologists will not suggest an in-depth workup for the disease.
Dr. Beth Karlan, a gynecologic oncologist at UCLA Medical Center, says, “In certain high-risk women, who have either inherited a defect in a gene called BRCA1 or 2 or other associated genes with hereditary ovarian cancer, you should undergo an ultrasound of the pelvis—trans-vaginal ultrasound—and a CA-125 [blood test], because it’s the best we have at the current time.”
But these tests are only routinely available for women with the aforementioned family histories of cancer, inherited genetic conditions like Lynch syndrome (which is a kind of colorectal cancer) and/or women presenting with recurring symptoms of the disease.
In fact, according to the American Cancer Society, low-risk women may be better off skipping screening if they aren’t experiencing symptoms. “In studies of women at average risk of ovarian cancer, using TVUS [trans-vaginal ultrasound] and CA-125 [blood test] for screening led to more testing and sometimes more surgeries, but did not lower the number of deaths caused by ovarian cancer.” And so for that reason, they don’t recommend routine testing.
So while there’s no widespread screening method currently available, researchers are working hard to find one. As Dr. Karlan says, “finding an early detection method for ovarian cancer is really like the holy grail.”
Ovarian cancer is notoriously hard to detect in the early stages when it’s most effectively treated. That’s why women should evaluate their risk factors for the disease and be vigilant about possible symptoms and warning signs.