PAP Smear Diagnosis of Endometrial Cancer

By Frederick R. Jelovsek, M.D.,

Pap smears are used to diagnose cervical cancer. The cervix is the lower part of the uterus, the mouth of the womb. The Pap test is not very accurate for diagnosing endometrial cancer which is from up in the menstrual lining of the uterus. Only 50% of the time that endometrial cancer is present are the Pap smears positive for (glandular) cancer cells. This is not a high enough percentage to be used as the primary diagnostic test; endometrial biopsy is usually the diagnostic procedure of choice although D&C and hysteroscopy are also used.

Sometimes a Pap smear is suggestive of endometrial cancer rather than cervical cancer and we need to know what it means. G.L. Eddy and others recently looked at how Pap smears were read within 1 year of the diagnosis of endometrial cancer, Eddy GL, Wojtowycz MA, Piraino PS, Mazur MT. Papanicolaou smears by the Bethesda system in endometrial malignancy: utility and prognostic importance. Obstet Gynecol 1997 Dec;90(6):999-1003. They found that almost half the patients had a abnormal Pap. More importantly, if the Pap smear was suspicious for endometrial cancer, the cancer was a more severe type. In other words the cancer had invaded further or was of a more "malignant" type than in women who did not have a positive Pap.

This study means that if a woman has a Pap smear suspicious for endometrial cancer and she turns out to actually have cancer, there is a much higher chance that she will need more than a hysterectomy as treatment. Only less aggressive endometrial cancers that have not spread deeply into the muscle of the uterus can be treated with hysterectomy alone. More invasive or aggressive cancers need additional therapy such as radiation or chemotherapy. They also require more extensive surgery such as lymph node removal near the major blood vessels and biopsies. This often requires surgery by specially trained gynecologic oncologists (cancer surgeons).