A Pap smear involves the painless removal of cells from the cervix. It is a screening test for cervical cancer. The cervix is the lower part of the uterus and the entry to the birth canal. Despite what most women think few women die in the United States each year because of cervical cancer. You may know a friend who had a pap smear showing a pre-cancerous condition of the cervix, known as dysplasia. You may even know a woman who had a condition called carcinoma in situ of the cervix, but these abnormalities are not life threatening as long as a woman is under a doctor’s care and doesn’t ignore the condition.
The Pap smear was developed by Dr. George Papanicolaou in 1954. This painless technique has been responsible for saving tens of millions of lives world-wide since its use became popularized. The Pap smear is nothing more than an exam, by a health care provider, that involves the gentle brushing and removal of cells from the cervix to be examined under the microscope by a trained cytologist.
If you’re reading this you may be a woman trying to learn more about Pap smears or you might be someone who recently found out that she has an abnormal pap smear. Before we get started let’s put things into perspective about cervix cancer. In year 2005 the American Cancer Society reported that 662,870 women in the United States died of all forms of cancer. It breaks down as follows:
|Lung cancer deaths||79,560|
|Colon cancer deaths||56,660|
|Breast cancer deaths||40,410|
|Rectal cancer deaths||16,810|
|Ovarian cancer deaths||16,210|
|Pancreatic cancer deaths||16,080|
|Uterine cancer deaths||7,310|
|Multiple myeloma deaths||5,640|
|Stomach cancer deaths||4,780|
|Kidney cancer deaths||4,640|
|Bladder cancer deaths||4,210|
|Cervical cancer deaths||3,710|
|Esophageal cancer deaths||3,300|
For more information on the risk of various cancers in women visit
You can plainly see that although many women are afraid of cervical cancer very few women, comparatively die of this diseaser. That’s why the National Institutes of Health lists cervical cancer as a rare disease (remember I’m not talking about carcinoma in situ which is almost 100% curable, and is different from invasive cervical cancer!).
This is wonderful news and it means that visiting your health care provider regularly is tremendously important. Most of the women in the US who die of cervical cancer did not get regular pap smears! So, before you read any further understand that the Pap smear, which has been around for over 50 years, has made invasive cervix cancer a rare disease and death from cervical cancer rarer still!
The last point I’d like to make about Pap smears is that they are a screening test and not a definitive diagnosis. Pap smears help the health care provider determine which women need specific diagnostic tests such as colposcopy and cervical biopsies. If a pap smear indicates need to that a woman needs further diagnostic tests the actual diagnosis will require a biopsy.
So, exactly what is the cervix? What does it do? What is it made of?
The cervix is the lowest portion of the uterus. It can be seen through the vagina with the use of a vaginal speculum. During pregnancy the cervix acts as a valve and keeps the uterus from opening until a child is mature enough to be born. During labor the cervix opens to about 10 cms (4 inches) and allows the baby to enter the birth canal.
The cervix is covered with a thin skin called “epithelium”. It is a smooth surface very similar to the type of tissue that covers the inside of your lip.
The cervix represents an area where two types of epithelium (think of this as similar to skin cells) join. The “skin” of the cervix is covered with cells called squamous cells.
Squamous cells look like “omelets” stacked up 6 or 8 deep. The “skin” of the inside of the uterus is made up of columnar cells (think of these as being arranged like a column of beer cans). The cervix contains a vulnerable area where these two cells types join. This area is called the squamo-columnar junction or transition zone (T-Zone) and represents the changeover from one cell type to another. THE IMPORTANT PART to know is that it is specifically in the squamo-columnar junction or transition zone that cancer occurs.
When should I get my first pap smear and how often should I get one?
The American College of Obstetricians and Gynecologists most current guidlines are:
- Cervical cancer screening should start at age 21 year
- Women aged 21-29 years should have a Pap test every 3 years.
- Women aged 30-65 years should have a Pap test and an HPV test (co-testing) every 5 years (preferred). It is acceptable to have a Pap test alone every3years.
- Women should stop having cervical cancer screening after age 65 years if they do not have a history of moderate or severe dysplasia or cancer and they have had either three negative Pap test results in a row or two negative co-test results in a row within the past 10 years, with the most recent test performed within the past 5 years.
How common are Pap smear abnormalities?
About 55 Million Pap smears are performed in the United States each year. 3.5 Million of these Pap smears or 6% are abnormal and will require medical follow up. So just to put things in perspective remember that there are approximately 3700 cervical cancer deaths in this country each year. So, for every death attributed to cervix cancer there are 1000 abnormal pap smears! Calm down….you’re not alone if you have an abnormal pap smear.
What are the risk factors for Pap smear abnormalities and specifically for pre-cancerous changes?
The major risk factors for Pap smear abnormalities are:
- Having sex at an early age (before 18)
- Having sex with multiple sexual partners
- Having sex with someone who has had multiple partners
- Having sex with uncircumcised men
- A history of Chlamydia infection
- Obese women
- Multiple pregnancies
- The HPV Virus
- A family history of cervical cancer
What are the types of abnormalities that a pap smear can detect?
Pap smear abnormalities cover a range from the very mild to those that are of far greater concern. Before we can discuss pap smears, however, we need to discuss (a) the range of cervical cell abnormalities and (b) what these abnormalities look like on a tissue biopsy.
The Pap smear is NOT a biopsy, however. Instead, it takes a sample of cells that are normally shed by the cervix and let’s the health care provider know when a biopsy might be necessary. The definitive diagnosis of an abnormality is made with a biopsy. Now here’s a photomicrograph of what a cytologist might see when looking at an abnormal cell.