Ovarian cancer has no recognised pre-cancerous stage like cervical or even endometrial cancer. Therefore, there is no simple and reliable way to screen for ovarian cancer in women because it generally has no signs or symptoms. However, screening is advisable when there are known risk factors such as obesity, nullipara or endometriosis or having a specific familial type of cancer like breast, ovarian (especially BRCA related), colon and endometrium.
Most studies on ovarian cancer screening try to detect early-stage cancer using pelvic ultrasound and tumour markers like CA 125. The result, in general, was quite disappointing as it may cause more harm than good. However, ultrasound detection of any pelvic mass may allow more straightforward surgery or even fertility-sparing surgery, which is generally not possible if had progressed to stage 3C.
A particular type of ovarian cancer produces CA 125, but a normal CA 125 is common in early-stage ovarian cancer and does not exclude malignancy. Similarly, a raised CA 125 does not necessarily due to a cancerous mass. Pregnancy, pelvic infection, endometriosis or even menstruation are known to cause raised CA 125. Other tumour markers, like AFP, beta HCG and CEA, are generally not used for screening but after a mass has been detected clinically or by imaging.
Although specific screening for ovarian cancer is not advisable, women who are screened for cervical cancer will be asked for any known risks of ovarian or endometrial cancers and offered ultrasound in the same setting and, if indicated sampling of the endometrial lining. This represents a more comprehensive screening and look out for female reproductive cancers.