The Papanicolaou test, or Pap smear is a test of the cervix looking for precancerous or cancerous cells. It is one of the most successful screening tests available and has reduced the incidence of cervical cancer dramatically. The pap smear is done by placing a speculum in the woman’s vagina and then using a soft instrument to collect cells from the cervix. Although having a speculum placed can be unpleasant, the Pap smear should not be a painful test.
Before the advent of Pap smear screening, cervical cancer was the leading cause of cancer deaths in women in the US. There are now only about 4,000 deaths from cervical cancer per year in the US. This is still 4,000 too many, but a huge improvement over what existed before the Pap smear became standard. Most of the cases of cervical cancer in the US are from either recent immigrants who have not had the benefit of regular screening or women who have not had a Pap smear in many years. It is very rare to find cervical cancer in a woman who has undergone regular screening and has been compliant with follow-up.
The Pap smear results are not just normal or abnormal.They can come in a wide range of results giving some clue to the degree of abnormality. Paps can be normal, ASCUS, LGSIL, HGSIL, or suspicious for carcinoma. Abnormal Pap smears are generally followed up with a colposcopy, an examination of the cervix with a microscope. Biopsies are often taken with the colposcopy that can give more accurate information about the degree of abnormality after an abnormal Pap smear.
There is the possibility of both false negative and false positive results with a Pap smear. False positives will be found out by colposcopy or follow up Paps. Fortunately for most people the development of cervical cancer is a very slow process. The cervix goes through a series of precancerous changes called dysplasia before cancer develops. In the majority of cases, this process takes many years. Dysplasia is generally easily treatable with an office procedure called a LEEP cone biopsy. If a Pap smear has a false negative result, chances are it will be positive the next time the screening is done. Because cervical cancer is slow to develop, changes should still be in the dysplasia category even after a false negative.
The optimal interval between Pap smears is undergoing some rethinking at the present time and this is controversial. The traditional approach is to do a Pap smear screening every year. Many gynecologists are still recommending this screening interval. Newer recommendations reduce the screening to every 2-5 years. In women over 30 some people recommend doing a second test looking for high risk HPV with the Pap smear. In any case, it is important to visit the doctor yearly for a physical exam including a bimanual exam and a breast exam.