In a woman who has ovarian cancer, a rise in CA-125 usually means that the disease has progressed or come back (recurred). A decrease in CA-125 usually means the disease is responding to treatment.
In a woman who has not been diagnosed with ovarian cancer, a rise in CA-125 may mean a number of things. While it can mean that she has ovarian cancer, it can also indicate other types of cancer, as well as several diseases such as endometriosis, which are not cancer.
In healthy women, an elevated CA-125 usually does not mean ovarian cancer is present. Most healthy women with an elevated CA-125 do not have ovarian cancer, or any other cancer.
Any woman with an abnormal CA-125 test needs further tests. Sometimes surgery is needed to confirm the cause.