September 17, 2018
September 17, 2018
Is there a screening test for ovarian cancer, and should I get it?
Many of my patients ask me about ovarian cancer screening, and unfortunately, I have no reassuring answer for them.
Take Linda,* for example, a 53-year-old patient who sees me for regular gynecologic checkups. She tells me her grandmother died from a “probable ovarian cancer,” and no one knows more details since it was a long time ago. Due to this family history, her prior gynecologist had been ordering yearly pelvic ultrasounds for her as a screening test, and she wonders if I recommend that she continues this. She also asks about CA-125 testing.
Many people know someone who has had ovarian cancer, as it is diagnosed in 1 in 78 women. In other words, all women have about a 1% risk of ovarian cancer in their lifetime. Compared to some other cancers, this is low. Breast, colon, lung, and skin cancers are much more common (for example, breast cancer affects 12% of women).
Although relatively uncommon, ovarian cancer has a significantly worse prognosis than many other cancers. This is primarily because the majority of women are not diagnosed until the cancer has already spread outside of their ovaries into their abdomen, and sometimes to other, more distant parts of the body. Treatment usually requires both surgery to remove the bulk of the tumor, as well as chemotherapy to try to eliminate the remaining cancer cells. Often, even with aggressive treatment, some cells remain, and over time are able to grow into large tumors again.
Thus, a screening test to find cancer at early, or pre-cancer stages would be ideal. The mammogram can find tiny tumors in the breast, and the PAP smear can find abnormal cells on the cervix before they turn into cancer. What screening is available for ovarian cancer?
The two widely used tests that have been used in an attempt to find ovarian cancers early include the trans-vaginal pelvic ultrasound, as well as blood tests called “tumor markers,” such as CA-125. These have been assessed in a number of studies and, unfortunately, do not appear to save lives in average-risk women. This is because both of these tests are far from perfect. Neither tends to read as abnormal when cancer is in its earliest stages, and may miss many early cancers.
More importantly, these tests will often lead to a suspicion of cancer when none exists, which leads to surgery. Surgery itself has risks, and there is increasing data showing that early removal of ovaries leads to increased harm to women as well. Thus, the current data indicates that the benefits of screening – for most women – are outweighed by the harms, and screening is NOT recommended.
So what do I recommend? For patients with a family history of ovarian or certain other cancers, I recommend considering an appointment for genetic counseling. This appointment will include discussion of blood tests available to check for mutations (changes) in genes that are associated with cancers. The most well-known mutations associated with breast and ovarian cancer are the BRCA mutations.
When a woman tests positive for one of these mutations, she will receive counseling on its implications, including which cancers she may be at risk for, and which other family members may be affected similarly. Increased surveillance with yearly ultrasound and CA-125 may be considered, as well as risk-reducing treatments or surgeries (i.e. removing the ovaries and fallopian tubes). In high-risk women, the benefits of these screening tests may outweigh the potential risks of harm.
So for Linda, with the possible family history of ovarian cancer in a grandmother, what did I tell her? I understand the fear of cancer can significantly affect a women’s life. I advised she consider a referral for genetic counseling and testing, to gather more information to guide our decisions. She accepted this referral, and we are awaiting results. If she does test positive for a mutation, there is a lot to talk about. If not, she can breathe a sigh of relief, knowing that she is not at elevated risk, and no screening tests are recommended.
For other patients with a family history of ovarian cancer who do not have genetic testing done, I discuss the option of screening individually. I make sure they know that the risk of unnecessary cost, stress, surgery, and removal of ovaries is significant. We discuss what can be done to reduce the risk of ovarian cancer, including a healthy weight and active lifestyle. I review the symptoms of ovarian cancer, including abdominal pain, bloating, and unexplained weight loss and loss of appetite.
For more information about ovarian cancer, screening tests, and the most recent recommendations, the following sources can be helpful: American Cancer Society; National Comprehensive Cancer Network; US Preventative Services Task Force; The American College of Obstetricians and Gynecologists.
*name changed to protect privacy