Pap Test: An accurate test that can predict the onset of cervical cancer

Last Updated December 20th, 2021

What is Cervical Cancer?

The cervix is the opening to the uterus. Cancerous growth in the tissues of the cervix is called cervical cancer. It is a largely preventable disease, but it is known to affect 500,000 women each year, 80% of whom are from developing countries. The primary cause of both precancerous lesions as well as cervical cancer is infection by Human papillomavirus (or HPV). The HPV infection is the most common sexually transmitted disease in the United States, where one in four people are infected by it. The infection caused by HPV undergoes spontaneous remission. There is also a 10- to 20-year lag between precancerous lesion formation and cancer, which is ample time to resolve the issue.  

Quick Facts

  • Cervical cancer tends to occur in midlife and is most frequently diagnosed in women between the ages of 35 and 44.
  • In the United States, Hispanic women are most likely to get cervical cancer, followed by African-Americans, Asians and Pacific Islanders, and whites.

Cervical Cancer Estimates

Cervical cancer is the most common cancer affecting women in 45 countries of the world, and it kills more women than any other form of cancer in 55 countries. These include many countries in sub-Saharan Africa, many in Asia (including India), and some Central and South American countries.

In the year 2012,

  • 528,000 new cases of cervical cancer (cancer or cervical cancer?) were diagnosed worldwide, about 85% of which occurred in low- to middle-income countries.
  • Of these, 266,000 women died of cervical cancer worldwide; almost 9 out of every 10 of these, or 231,000 women in total, died in low- to middle-income countries. In contrast, 35,000, or just 1 out of every 10 of these women, died in high-income countries.

The study concluded, therefore, that the socioeconomic conditions and lack of proper education prevent the early treatment of cervical cancer in such regions.

For the year 2019, the American Cancer Society’s estimates are:

  • About 13,170 new cases of invasive cervical cancer will be diagnosed.
  • About 4,250 women will die from cervical cancer.

Why is Screening for Cervical Cancer Effective?

An ideal screening test must be:

  • Minimally invasive and acceptable to the subject
  • Cost-effective and efficacious in identifying the disease in its early stages

Cervical cancer is a good candidate for early screening. It is probably the only gynecological disease that satisfies all WHO guidelines for a disease that requires the implementation of a screening program. These are:

  • Existence of well-defined premalignant lesions in the early stages
  • The long latent period in which premalignant change or occult cancers (cancer of unknown origin) can be detected and effectively treated
  • A clearly defined viral etiology (cause) which could be incorporated as a marker in a mass screening program
  • Easy and direct access of the uterine cervix for both examination and sampling
  • Effective treatments available for all premalignant changes

Screening programs for cervical cancer have been instituted in developed countries for decades. Over a period of time, they have been shown to be effective in reducing the overall mortality from this disease. One such example is Sweden, where the Pap smear test has shown a 53% reduction in mortality rates. Such programs, however, can only be made to work provided the necessary infrastructure and funds are available.

The Pap Test

The Pap smear test or Papanicolaou test, developed by George Papanicolaou in 1927, helps to identify precancerous or cancerous cells of the cervix. It is a type of conventional exfoliative cytology. During the process, cells are gently scraped away from your cervix and examined under a microscope. It may be mildly uncomfortable, but never painful and it is the best test to detect cervical cancer as early as possible.

Who benefits from a Pap smear test?

All women over the age of 21 will benefit from a Pap smear test. Over the age of 21, and up till the age of 30, a Pap smear test is recommended every 3 years. Over the age of 30 and between 65, if the pap test and HPV test are negative, then it should be taken every 3-5 years.

Some women are at increased risk of getting cancer or infection. Some of them are:

  • Patients who are HIV-positive.
  • People with a weakened immune system due to chemotherapy or an organ transplant.
  • Having been exposed to diethylstilbestrol (DES) (a synthetic estrogen) before birth

If you are over 30 and have had three normal pap tests in a row, request your doctor to conduct a pap test every five years and to include HPV (human papillomavirus) screening. HPV is a virus that causes warts in human beings.HPV Types 16 and 18 put you at an increased risk of developing cervical cancer.

Women over the age of 65 with a history of normal Pap test results may be able to stop having Pap smears in the future.

Things you must not do before a Test

  • Do not take the test when you are menstruating as it may affect the results. In such a case, inform the doctor.
  • Avoid sexual intercourse, douching or the use of spermicidal products before the pap smear test, as this, can affect the results.
  • Relax before the test. Take deep breaths and try to stay calm. Only then will the pap smear test go smoothly.
  • It is okay to have a test during the first 24 weeks of pregnancy after which the tests may be more painful.
  • Waiting for 12 weeks after giving birth improves the accuracy of the results.

What Happens during a Pap Smear Test

At the beginning of the procedure, you’ll be asked to lie on your back on an examination table with your legs spread and your feet resting in supports called stirrups. The doctor slowly inserts a device called a speculum into your vagina. This device helps keep the vaginal walls open, providing access to the cervix. Your doctor will then scrape a small sample of cells from your cervix.

There are a few ways your doctor can take this sample. Some of them use a tool called a spatula, some use a spatula and a brush, and some others use a device called a cytobrush, a combination spatula, and brush. The cell sample will be preserved and later sent to a lab for further testing for the presence of abnormal cells. The Pap smear test usually takes anywhere between 10 and 20 minutes to complete.

How Long before you get the Test Results?

Getting the test results for Pap and HPV should take anywhere between 1 and 3 weeks. Most of the time, the results will be normal. Three weeks after the test, if you are still to receive the results, then call the doctor’s office and ask for an update. If he/she schedules an appointment as a follow up, make sure you are there for it.

What the Test Results Mean

  • A negative test result is a good thing. This means there are no strange cells on your cervix. The next Pap test will be on the scheduled date after three years, and you won’t need any soon or immediately.
  • A positive test result does not necessarily mean that you have cancer. Even if you have a case of inflammation, it could lead to a positive result. Just to be sure, the doctor may run another pap test or conduct the tests described in the next section.

After the Initial Test

After the test is over you might experience mild discomfort or cramping as a result of the scraping. In certain cases, patients are known to suffer internal bleeding. If this continues after the test, then inform the doctor.

Depending on the test results, the doctor may recommend more frequent pap tests. He may also recommend a procedure called colposcopy. During a colposcopy exam, the doctor uses light and magnification to help see vaginal and cervical tissues more clearly.

A biopsy also may be done, where a tissue sample from the cervix is removed for further analysis. When doing so, he may swab your cervix with a solution to limit bleeding. 

Other Screening Methods

Other screening techniques for cervical cancer include:

  • Fluid sampling techniques with automated thin layer preparation (liquid-based cytology)
  • Automated cervical screening techniques
  • Neuromedical systems
  • HPV testing
  • Polar probe
  • Laser-induced fluorescence
  • Visual inspection of cervix after applying Lugol’s iodine or acetic acid  
  • Speculoscopy
  • Cervicography

Limitations of the Pap Test

In recent times, scientists have acquired a better understanding of the natural history of cervical cancer. There is also increasing evidence for the putative role of the human papillomavirus (HPV) in its causation. These have now prompted investigators to find viable alternatives to conventional exfoliative cytology. The observed limitations of the Pap test are:

  • Incorrect and inadequate sampling in 5-10% of the cases
  • Only up to 20% of harvested cells are transferred on the slide, leading to a reduction in the sensitivity of the test
  • Mean sensitivity is only between 55% and 60%
  • Reported false negative rates varying from 25% to 50%
  • Reported false positive rates varying from 15% to 20 %
  • Cytological abnormalities are interpreted differently by different observers, which makes it quite subjective and reduces reproducibility

Because of these problems, several techniques have been recently developed to automate the various steps of Pap smear preparation and processing, in order to try and improve the sensitivity and specificity of conventional cervical cytology.

Symptoms of Cervical Cancer

The most common symptoms of cervical cancer are:

  • Bleeding between periods
  • Bleeding after sexual intercourse
  • Bleeding in post-menopausal women
  • Discomfort during sexual intercourse
  • Vaginal discharge with a strong odor
  • Vaginal discharge tinged with blood
  • Pelvic pain

How important is the Pap smear test?

Despite all its limitations, the Pap test is a very simple and minimally invasive test for cervical cancer, suitable for all age groups of women, particularly those who are sexually active and below the age of 65. If this simple test is not performed, serious complications can occur in later life. A smear does indeed save a life.



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